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;ntornAtion US Department of Commerce NOAA Coastal Services Center Library 2234 South Hobson Avenue Charleston, SC 29405-2413 Maine's Intertidal Habitats I-IT 393 .M2 L37 V 1985 Executive Department Maine State Planning Office November 1985 Maine's ,Intertidal Habitats A Planner's Handbook A Report Prepared for the Maine State Planning Office (edited by Robert Deis) by Bigelow Laboratory for Ocean Sciences West Boothbay Harbor, Maine Executive Department Maine State Planning Office November 1985 US Deparbnent Of COMMeree NOAA Coastal Services Center Iam=7 2234 South Robson Avenue Charleston, SC 29405-241S Cover Photo. A wide gravel beach on Mount Desert Island. Cite this publication as follows: Larsen, P. F. and L. F. Doggett. (edited by R. Deis). Maine's Intertidal Habitats: A Planner's Handbook. Maine State Planning Office and Bigelow Laboratory for Ocean Sciences. 1985. Financial assistance for preparation of this document was provided by a grant from Maine's Coastal Program, through funding provided by a U.S. Department of Commerce, Office of Ocean and Coastal Resource Management, under the Coastal Zone Management Act of 1972, as amended. PREFACE Planning Considerations and Coastal Resource Development Since 1977, as part of Maine's Coastal Program, the State Planning Office has published a series of handbooks to assist private citizens and developers, as well as members of local planning boards and professional planners, with convenient guides to the management of coastal resources. These handbooks provide the reader with sufficient technical background to communicate suc- cessfully with specialized scientists and technicians when considering developments proposed for shoreline and intertidal sites. They also serve as users'guides to specialized maps displaying coastal data. Non-technical language is used as much as possible without diminishing the accuracy of the information. Development and utilization of the natural resources within Maine's coastal area must and will continue for the benefit of all. Protection of the natural values provided by those resources for future as well as current use is a fundamental public responsibility for decision makers in the present, Deci- sions affecting the fate of the public interest in coastal resources are being made regularly at the local, state and federal levels of government. Typical situations include local planning board deci- sions on shoreland and subdivision development proposals, state Board of Environmental Protec- tion decisions on conditions attached to major development proposals under the Site Location Act, and decisions by the U.S. Army Corps of Engineers on permits to construct harbor improvements. In most cases, development proposals may move forward once assurance is given to regulatory authorities by developers that reasonable care will be taken to protect public environmental values. Protection can usually be achieved by employing construction practices or safeguards shown to pre- vent or minimize permanent environmental damage, by refraining from known detrimental practices, or by relocating the proposed activity to a more suitable site. The first step toward assuring that a development will meet the resource protection test is an awareness by both the developer and the regulatory agency of resource values likely to be affected by the proposed activity, so that development plans may be designed to provide the necessary pro- tection. In the following descriptions of various kinds of intertidal habitats, resource values likely to be af- fected by development are mentioned. Thus, the reader is alerted to some of the planning considera- tions associated with particular types of marine geologic environments which may be impacted by various kinds of development activity. This particular publication, Maine's Intertidal Habitats: A Planner's Handbook, is a revision of an earlier report on the ecology of Maine's Intertidal areas by Peter Larsen and Lee Doggett of the Bigelow Laboratory for Ocean Sciences.' The original report, addressed to the scientific community, has been edited by environmental writer Robert Deis, to publish a version with the planning com- munity in mind. The text has been augmented with discussion of the potential ecological impacts of development proposed for intertidal areas. State Planning Office staff principally responsible for this publication are David Keeley, Manager for Maine's Coastal Program, Richard Kelly, who designed the publication, and Harold Kimball, who coordinated the publication process. Larsen, P.F. and L.F. Doggett. 1981. The Ecology of Maine's Intertidal Habitats. Maine State Planning Office and Bigelow Laboratory for Ocean Sciences. TABLE OF CONTENTS Page List of Figures 1 Introduction 3 Chapter 1: An Intertidal Ecology Primer 7 Tides 7 The Ecological Significance of Tidal Height 9 Wave Exposure 10 Other Ecological Factors 10 Zonation 11 Chapter 2: General Planning Considerations 15 First Steps, Basic Factors 15 Petroleum Hydrocarbons 16 Dredging 17 Construction 18 Shipping and Boating 18 Biocides (pesticides, herbicides, and fungicides) 19 Heavy Metals 19 Dams 20 Toxic Substances and Hazardous Wastes 20 Recreational Activities 21 Commercial Digging of Clams and Worms 21 Thermal Effects 21 Sewage and Organic Wastes 21 Chapter 3: Maine's Intertidal Environments 25 A Closer Look 25 Sand Beach Habitats 27 Sand Flat Habitats 29 Mud Flat Habitats 30 Gravel Beach Habitats 31 Cobble Beach Habitats 32 Boulder Beach Habitats 33 High-energy Rocky Shore Habitats 34 Low-energy Rocky Shore Habitats 34 Salt Marsh Habitats 35 Chapter 4: A Sampler of Intertidal Species 39 LIST OF FIGURES Figure Page Cover. A wide gravel beach on Mount Desert Island Cover 1. View along the boulder beach at Roque Bluffs 2 2. Hodgdon Cover mud flat in Boothbay Harbor 6 3. A typical spring-neap tidal cycle drawn from predictions at Portland, Maine, April 1977 8 4. The various tidal levels and ranges discussed in the text 8 5. The effect of the degree of wave exposure on the width of the littoral zone 10 6. The salt marsh, just north of Route 1-95 on the Cousins River, Yarmouth 14 7. The sand beach at Reid State Park, Georgetown 24 8. Marine Geologic Environment Map and Legend 26 9. A large sand flat at the head of Bailey's Mistake in Trescott 29 10. Looking up a transect on a cobble beach at Kennebunkport 32 11. The low-energy rocky shore in East Waldoboro 35 12. The high-energy rocky shore at Cape Neddick 38 13. Soft-shelled clam (Mya arenaria) and baltic clam (Macoma balthica) 39 14. Blatic clam (Macoma balthica) 40 15. Dog whelk (Nucella lapillus) 40 16. Common periwinkle (Littorina littorea) 40 17. (Corophium voluntator) 41 18. Rock barnacle (Balanus balanoides) 41 19. Sand worm (Nereis virens) 41 20. Cone worm (Pectinaria gouldii) 42 21. (Oligochaetes) 42 22. Acorn worm (Saccoglossus kowalevski) 42 23. Title 38, �471-478, Alterations of Coastal Wetlands 43 1 FIGURE 1. View along the boulder beach at Roque Bluffs. 2 INTRODUCTION Between the limits of high tide and low tide essential. Thus, a primer of intertidal ecology is lies an area that is one of the most important provided in Chapter 1. and dynamic parts of Maine's complex coastal Chapter 2 reviews the general planning con- ecosystem. Its living and non-living resources siderations of various human activities along provide us millions of dollars in commercial the coast and the potential impacts of those ac- gain as well as a great wealth of opportunities tivities on intertidal environments. The goal of for recreational, educational and aesthetic en- this discussion is not to discourage or argue joyment. Of necessity, we go to this area to against the development and use of our coast- build our piers, wharves and other marine trans- line. It is, rather, meant to encourage and pro- portation facilities. We also go to dig clams, to vide some guidelines for sensible planning. harvest mussels and seaweeds, to study in- Along the coast, as elsewhere, proper planning teresting ocean creatures, to collect beautiful can direct development and other activities to reminders of seaside trips, and to swim and the most appropriate sites, maintain the build sand castles. It is called the "intertidal benefits of multiple uses, reduce or prevent un- zone", a unique strip of land found along our necessary adverse impacts on the environment, coastline where the land and sea meet. and help developers avoid costly delays and This handbook, developed by Maine's legal conflicts. Basically, the impacts describ- Coastal Program and researchers from the ed are of a common or major nature. An attempt Bigelow Laboratory for Ocean Sciences, has a has been made to avoid giving equal emphasis two-fold purpose: to provide an introduction to to comparatively minor problems. the ecology of Maine's intertidal zone; and, to Chapter III provides a concise overview of the help coastal residents, town planners and geological and biological characteristics of developers understand how to use and protect nine basic types of intertidal habitats. In addi- intertidal habitats in ways that will insure long- tion, it describes some of the special planning term productivity and usefulness for genera- considerations associated with them. Although tions to come. this handbook can stand alone as a reference, it For the handbook to be as meaningful as is more helpful when used in conjunction with a possible, some knowledge of the natural and set of coastal resource inventory maps entitled, man-made factors affecting intertidal areas is "The Coastal Marine Geologic Environments 3 Maps." These maps show the locations of winter flounder and other commercially valuable distinct coastal environments, such as mud- species, small intertidal organisms comprise a flats and beaches. The features and uses of major source of food and a crucial link in the these maps are described in Chapter 3. (More complex food chains of the sea. A great number detailed information can be found in the com- of those commercial species also spend the panion volume to this handbook, The Geology of early stages of their lives in intertidal habitats. Maine's Coast, also available from the Coastal Many kinds of shorebirds and waterfowl, Program.) sought by both birdwatchers and hunters, feed Chapter 4 describes some of the creatures in- in intertidal and shallow subtidal habitats. habiting Maine's intertidal areas. Each year, tourists and Maine residents The harvesting of clams, bloodworms and generate millions of dollars of economic activi- sandworms from intertidal mudflats employs ty through their recreational use of the inter- thousands of Maine residents (as diggers, tidal zone. They come to swim, sunbathe and wholesalers, shippers, processors and retailers) surf fish on Maine's beautiful beaches. Some and brings tens of millions of dollars into the drive thousands of miles to gaze at the magnifi- state each year. Smaller fisheries exist for cent splendor of Maine's fabled rocky shores. various seaweeds (extracts of which are used For these and other reasons, the people of as food additives and fertilizers) and for other Maine have a great stake in the wise use of the species, such as periwinkles. intertidal habitats along our coastline. It is in- The intertidal zone also provides many in- tended this handbook will help ensure that direct economic benefits. For lobsters, crabs, these habitats retain their unique values now and in the future. 4 FIGURE 2. Hodgdon Cove mud flat in Boothbay Harbor. owl F7 ni@ CHAPTER 1 AN INTERTIDAL ECOLOGY PRIMER Ecology is the study of the inter-relationships water) to the terrestrial (always above water). among living organisms and their environment. And, though the two terms are commonly used In the most general sense, this includes people interchangeably, our discussion will differen- and many of their activities. tiate between them in the beginning. First, we Because such an all-encompassing field is will focus on the true intertidal zone, discuss- so vast in scope, it has been divided into sub- ing the effects of tides and how living units, or branches, of study that are more nar- organisms respond to tidal cycles. Then, the rowly defined and easier to research and under- concept of wave exposure will be introduced to stand. Of course, the basic natural laws which show how important this is as a modifying fac- govern life apply equally to all branches of tor. ecology. But the focus of each branch involves Tides a unique set of plants, animals and physical conditions. In a sense, tides are very long waves created Intertidal ecology is the study of the relation- on the ocean by the gravitational pulls of the ship among the living and nonliving com- sun and moon. They should not be confused ponents of the intertidal zone, the intriguing with so-called "tidal waves," which are large, area between the high and low tide lines. The destructive waves caused by earthquakes bounds of the intertidai zone are not defined by rather than gravitational pull. Tides occur any single high or low tide line, since these throughout the ocean, though they are most points shift considerably during the complex easily noticed along the coast, where their rise cycles exhibited by tides. Furthermore, the and fall alternately covers and uncovers a por- biological boundaries of the zone can be wider tion of the shoreline, the intertidal zone. or narrower than the actual tidal range due to Due to the combined effects of the gravita- modifying influences of other factors, particu- tional pulls of the sun and moon and the earth's larly wave exposure. rotation, there are normally two low-to-high However, ecologists do distinguish between tidal cycles each day (more accurately, every 24 the truly physical intertidal zone and the "Lit- hours and 50 minutes). The highest and lowest toral Zone", the region where biological com- points reached by these semi-diurnal, or twice- munities grade from the subtidal (always under- a-day, tides vary during the year. When the 7 I earth, moon and sun are aligned in space, highest spring tide. Each part of the substrate which usually occurs at or shortly after the full - the rock, sand, mud, and gravel - in this moon and new moon, the pulls of the sun and zone is entirely covered by ocean water at least moon reinforce each other. Both are pulling in once a year during the highest spring tide and the same direction. This makes the high tides completely exposed to the atmosphere at least higher than average, the low tides lower, and once a year-, during the lowest spring tide. Dur- the tidal range - the difference between the ing the extreme neap tides of the year the sea high and low tides - greater. These monthly covers the least amount of area above mean tide periods of relatively great tidal ranges are call- level at high tide and exposes the least arnount ed "spring tides", the term coming from the an- of bottom at low tide. (See Figure 4). cient Germanic verb springen (to leap up). The Most daily tides have a range somewhere bet- smallest tidal ranges, called neap tides, occur ween the extremes of the neap and spring tides. when the earth, moon and sun form a right For this reason, it is useful to speak in terms of angle to each other at the half-moon phase. A "mean high water" or "mean low water", which complete spring-to-neap-to-spring tide cycle simply refers to the average positions of high occurs every two weeks, as a result of the rela- and low water during an average tidal cycle. tionship to the moon's monthly orbit. This cycle "Mean tidal level" is the term used to denote is illustrated in Figure 3. the overall average level of the water, the point Monthly cycles are not the only regular midway between the highest and lowest tide changes noted in tidal ranges. During the year, marks. the distance between the earth and sun varies. So, too, does the angle at which the earth "faces" the sun. Thus, there are annual varia- FIGURE 4. The various tidal levels and ranges tions in tidal range. In Maine, for example, the discussed in the text. greatest tidal ranges occur during spring tides occuring in the spring and fall. EXTREME HIGH WATER SPRING Another important factor controlling tidal MEAN HIGH WATER range along our coast is the shape of the Gulf of EXTREME SPRING EXTREME HIGH WATER NEAP Maine and Bay of Fundy. In general, their con- TIDAL RANGE (largml tidal range) 7. figurations lead to greater tidal ranges the ME N TIDA EXTREME NEAP -MEAN TIDAL LEVEL RANGE TIDAL farther east one goes. The mean tidal range in RANGE (1111t lid' 111-911 Maine varies from about eight feet (2.4 meters) EXTREME LOW WATER NEAP in Portland to eighteen feet (5.5 meters) in the MEAN LOW WATER Lubec/Eastport area. This is significant EXTREME because the intertidal zone is normally wider LOW WATER where there is a larger tidal range (depending SPRING on the slope of the shore). The physical intertidal zone, then, is defined as that area between the extreme low water mark and the extreme high water of the year's FIGURE 3. A typical spring-neap tidal cycle drawn from predictions at Portland, Maine, April 1977. 10 9 8 7 Z 6 4 5 W W 4- 3- 2 MEAN LOW WATER 0 -11 22' 23 '24 25 26 27' 28' 29 30 2_1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17' 113 19 20 21 T I M EIN DAYS 8 The Ecological Significance of Tidal Height type of geological substrate (i.e., whether the shoreline is composed of sand, gravel, rock, The plants and animals that live in the inter- etc.) and certain other factors, the tide-related tidal zone are, for the most part, creatures of the conditions affecting these layers determine the sea and are thus closely related or very similar kinds of plants and animals that can live within to subtidal species. Like all marine organisms, them. intertidal plants and animals are dependent on The upper intertidal region, between the ex- the sea for their oxygen and food supplies, the treme high water spring and mean high water removal of body wastes, and as a medium in lines is one step short of being a truly terrestrial which to reproduce and disperse their offspring. environment. It is covered by spring tides on However, living in the intertidal zone requires only a few days of each month and organisms certain unique physiological adaptations. By living there must withstand many days of con- and large, the greatest problem faced is dessi- tinuous exposure to the atmosphere. This is a cation - drying out - during periods of ex- harsh situation very few species can tolerate. posure to the air. Life began in the sea, and The ribbed mussel, Geukensia demissa, is such before survival could be assured on land, a species that occurs in Maine. mechanisms had to be evolved that would pre- The area between mean high water and ex- vent individual organisms from drying out. We treme high water neap offers less harsh condi- see the ultimate results of this evolutionary pro- tions, though plants and animals residing there cess in land animals that have developed must still tolerate extended periods of ex- special external membranes (skin), complex ex- posure - up to 24 hours just above the extreme ecretory systems that conserve body water, and high water neap line, increasing to several days internal respiration systems (lungs). These as the extreme high water spring level is ap- adaptations also serve to maintain relatively proached. constant temperatures and other physiological Organisms living between the high and low conditions within an individual land organism. neap tide lines are exposed to the air for some In contrast, the rate of metabolism in marine period of hours during every tidal cycle. This invertebrates (ocean species without skeletons) means they must be able to bear the effects of is generally more strongly influenced by en- exposure on a regular basis. But, since they are vironmental temperatures. At colder tempera- also covered by the tide during each tidal cycle, tures, they feed, respire, and grow more slowly they do not have to be adapted to surviving than at higher temperatures. more than a few hours of exposure at a stretch. Thus, as opposed to terrestrial species, most Organisms living between extreme low water marine invertebrates are not greatly adapted to neap and mean low water, receive somewhat drastic variations in environmental conditions. less exposure to the atmosphere and are con- Intertidal plants and animals must, by necessi- tinuously submerged for days at a time during ty, have some adaptations that allow them to the month. Those in the lowest intertidal area, survive the comparatively harsh extremes that between the mean low water and extreme low occur during periods when they are exposed by water spring lines, are submerged most of the low tides. However, they are not nearly as well month and exposed to the atmosphere on very adapted in regard to physiological prevention of few days. In fact, this shoreline environment is dessication or temperature regulation as land not greatly different from the constantly- organisms. They can survive exposure for short submerged subtidal region. daily periods, but not for considerable lengths During low tide periods, organisms living of time. above the low tide level are subjected to This makes the periodic variations in tidal stresses far greater than those in the subtidal range a crucial ecological factor. It is, in fact, realm. These conditions include the extreme the primary influence that determines where cold of winter, the extreme heat of summer, the different kinds of intertidal species can survive drying action of the wind, and stress caused by along the shoreline. the influx of fresh water during heavy rains As shown in Figure 4, the cyclic variations in (most marine species can't survive long in fresh tidal height create fairly distinct "layers" within water). the overall intertidal zone of a shoreline. Each Because of the progressively harsher condi- layer is affected by a particular set of en- tions in the intertidal zone between the extreme vironmental conditions based on tidal fluctua- low water spring and high water spring levels, tions. Their horizontal width depends on the the intertidal environment can be considered to slope of the shoreline. In combination with the exhibit a "stress gradient". Not only does the 9 frequency of atmospheric exposure increase level, creating enough moisture for upper inter- steadily along this gradient in relation to the tidal plants; and animals to survive. The greater height of the layer, so does the length of the the exposure to wave action and the larger and period of continuous exposure that must be more consistent the waves are, the more pro- survived. nounced the effects on the landward extent of The severity of any given stress depends in the intertidal area. Figure 5 illustrates this part on the time of day at which a low tide oc- phenomenon. It graphically shows the dif- curs. For example, in winter, the threat of freez- ference between the physical intertidal zone ing is greater during low tides that occur in the and the biological intertidal zone, or "littoral cold early morning hours than during those oc- zone". A protected shoreline situation is curing at midday. In summer, low tides that oc- represented at the extreme left. The littoral cur in the early afternoon create a greater threat zone here is actually narrower than the physical of drying out than those which happen in the intertidal zone, because the lower intertidal morning, late afternoon or night. Similarly, area is occupied by organisms that are essen- heavy rains at high tide have little or no effect tially the same as those found sub-tidally rather on intertidal organisms, while a downpour at than by true intertidal species. In addition, the low tide exposes them to very low, u n-ocean I i ke absence of wave splash means water covers salinities which can cause extreme stress or the upperrnost intertidal area on only the most even death. extreme spring tides, once or twice a year. Other environmental dangers to organisms in Hence, intertidal organisms can't survive there. the intertidal zone include the threat of being The effects of increasing wave exposure are' crushed or dislodged by crashing waves or by shown at the right of the graph in Figure 5. As ice, logs and other debris that may grind along wave action increases the littoral zone moves the shoreface as the tide rises and falls. landward, higher on the shoreline. In highly ex- Wave Exposure posed shoreline, the littoral zone becomes wider than the intertidal zone. Under such con- Although tidal range defines the size of the ditions, indicated at the far right in the graph, physical intertidal zone, the effective biological some subtidal species can occur well up into intertidal zone in which intertidal species may the lower intertidal zone and many intertidal live can be expanded by wave action. This plant and animal species can live above the ex- depends on the degree to which a particular treme high water spring tide mark. stretch of shoreline is exposed to waves. Throughout the rest of this handbook, when In a shore completely protected from wave the term "intertidal zone" is used, it will mean action, such as a quiet, enclosed bay, the high the littoral zone, as opposed to the actual tide line determines how far up on the shore in- physical intertidal zone. tertidal organisms can live. The more a shore- line area is exposed to the wave action of the Other Ecological Factors open ocean, however, the higher the upper in- Tidal range and wave exposure are not the tertidal zone is pushed landward. This is only ecological factors that determine the ex- because waves break on the shore and wash tent of the intertidal zone along a given shore- over, or splash onto, elevations above the tide line area. A significant factor related to wave ex- posure, is the slant, or slope of the shoreline. The FIGURE 5. The effect of the degree of wave ex- slope of a shore affects how high waves will posure on the width of the littoral zone. surgelandward, before their energy is dissipated, as well as how quickly the water will drain off. In flat, wide shores, water from incoming waves does not surge and splash very high, but it drains off relatively slowly. This increases the itto,01 available moisture and lessens the threat of zone EXTREME dessication to the plants and animals living HIGH WATER there. As the slope of the shore becomes SPRING intertidol steeper, the extent and effect of wave surge zone fittoro and splash generally increase. However, with ,_",@,;to zonl, @@bj@JAO(Q@ one EXTREME increased steepness there is alto increased LOW WATER I SPRING drainage. On a rocky shore exposed to heavy INCREASING EXPOSURE wave action, wave surge allows some intertidal species to live at a higher level than on an ex- 10 posed flat shore. But in protected areas, the facing south receive more sunlight and warmth rate of drainage becomes the critical factor, than those facing north and, hence, are likely to and on very steep shores intertidal species are be drier when exposed. Heavily shaded places, usually limited to a lower level. such as cracks, crevices, and the undersides of The actual structure, or substrate, of the rocks, dry out more slowly than surfaces expos- shore - that is, what it's made of - is another ed to the sun and individuals living there are important factor controlling what species can less subject to dessication. live on it. Bedrock shores are very stable. Thus, The general climate of Maine cannot be they can be colonized by intertidal organisms underestimated in its influence on the com- that can establish a firm hold on the rock, such position of intertidal communities living along as barnacles. Sedimentary environments com- our shores. Many species need a summer posed of gravel, sand or mud, create very dif- temperature above a certain minimum to in- ferent conditions. For example, some cobble duce spawning. If that temperature is not reach- beaches can be quite inhospitable to most liv- ed in a given year, those species will not spawn. ing organisms because the individual rocks This limits how far north some intertidal may be moved regularly by waves, crushing the species will be found, even if other conditions organisms that might settle on or between might be suitable. An example is the American them. Likewise, since the small top layer of oyster. It is fairly common south of Maine, but grains on a sandy beach shift with every wave, exists here only in localized pockets of warm sand can be colonized only by fast-burrowing water. species which can constantly adjust their posi- The extremes of the Maine winter are another tions with respect to the surface of the beach. crucial climatic factor. During periods of ex- The composition of the substrate in a sedi- posure at low tide, freezing of tissue can be a mentary environment also controls the amount threat to intertidal organisms. The higher in the of water that remains in the spaces between the intertidal zone a plant or animal lives, the longer sediment particles at low tide. In a sand beach their exposure to the cold and the greater the with relatively large grains, water easily drains threat of freezing. away from between the particles, exposing any Ice is another danger. As the tide moves in organisms there to dessication and the temper- and out, floating chunks of ice can crush inter- ature extremes of the air. In mud and other fine- tidal organisms or dislodge them from their grained sediments, water remains in the "in- substrate. When ice settles on a tidal flat at low terstitial" spaces between grains at low tide. tide, the upper sediments and any organisms This affords the species living there a greater living on or in them can be frozen into the ice degree of insulation against environmental ex- and floated away with the next tide. Finally, dur- tremes. ing very cold weather the water in an intertidal In addition to dryness and temperature, area can freeze all the way to the bottom and marine organisms are sensitive to reductions in suffocate or freeze everything living there. the salinity, or salt content, of water. When they are put into water of lower salinity than sea- Zonation water, they tend to swell, as the fresher water As explained earlier, tidal cycles create fairly diffuses by osmosis into their bodies. Some in- distinct parallel bands in the intertidal zone that tertidal species have a limited ability to make are colonized by different kinds of plants and adjustments to salinity changes if they are not animals. This phenomena is called "zonation". too great and do not occur too rapidly. How- Zonation of the intertidal shoreline is a general ever, many species cannot survive any signifi- feature that can be seen nearly anywhere along cant salinity reduction and are thus unable to the Maine coast. It is most easily observed on a colonize places where build-ups of fresh water bedrock shore, where all the organisms live on tend to occur. Such places include sites where the surface of the substrate (as opposed to mud rivers or streams enter the intertidal zone and or sand, in which they can burrow). those where fresh water seeps in from the Between the subtidal area and dry land on a water table. Also included are exposed parts of rocky shore, zonation can be seen as a series of the intertidal zone during rains. The effect in dark red, brown, white and black or gray bands. this case is greater in the upper part of the The colors are those of the dominant species in zone, which is subject to the rain for a longer each band. The color of the red band results period of time. from the abundance of the red algae, Chondrus Light is a factor in the intertidal zone in much crispus, commonly called Irish moss, which the same way as on land. For example, areas predominates at the lowest intertidal level. The 11 brown band above it is colored by the various zone is the barnacle, Balanus balanoides, and rockweeds common to Maine, brown algae its relationship with the blue mussel, Mytilus from the genera Ascophyllum or Fucus. The edulis, and the snail known as the dog whelk, or notable white band is made up of a pavement of Nucella lapillus. In the upper level of the inter- barnacles (Balanus balanoides). The color of tidal zone, barnacles are the dominant animal the next highest band, often called "the black species, forming a solid, fairly wide, white zone," is caused by a film of dark-colored, blue- band. The upper limit of the barnacle zone ex- green algae that grows on the rocks. Like the ists at the point where inundation by high tides species that create these colorful bands, most is so infrequent the barnacles' tolerance limit other intertidal plants and animals live within a to dessication is reached. Barnacles can easily distinct layer of the intertidal zone, but they are survive the physical conditions of lower inter- generally not abundant enough to create a col- tidal levels. However, under natural conditions ored band of their own. they, are not found there in abundance due to Intertidal organisms are basically limited to biological pressures from the blue MUSSel and their particular band by their physiological the dog whelk. adaptations, which allow them to survive cer- In exposed shores, the lower edge of the bar- tain ecological factors. Some of these factoFs nacle zone is usually set by the upper limit of are physical and some are biological. the intertidal range of the mussel. Mussels are The upper limit at which a given intertidal superior to barnacles in their ability to compete species can exist is controlled primarily by for living space on the rocks. Therefore, in the physical factors, the most important being tidal area where both species can survive, the height and wave exposure. For example, the ex- presence of mussels tends to make it impossi- treme high water neap tidal level is a physical ble for barnacles to gain a foothold. So, the bar- boundary for those species that cannot tolerate nacle is relegated to colonizing a higher level, more than a few hours at a stretch out of the at which the mussels can't exist. water. In more protected shores, another pressure The more tolerant an animal is to such is added by the predatory dog whelk. Dog stresses as dessication, heat, cold and rain, the whelks prey on both barnacles and mussels. higher in the intertidal zone it can live. Thus, in They cannot stand as long an exposure to the the intertidal zone from low water up through atmosphere as barnacles. Thus, the lower limit the succeeding levels, one after another of the barnacle zone is set by the dog whelk's species drops out, and several with similar upper tolerance limit to clessication. Most bar- tolerances may drop out at one point. Those nacles that settle below this lines are devoured points where a number of species cease to ex- by the voracious snails. Barnacles can occur in ist can be considered the upper boundaries of abundance only above the level that can be the internal bands, or zones, of the overall inter- reached by dog whelks. tidal zone. Scientists believe that biological interactions In contrast to the upper boundaries, the similar to those between barnacles, blue lower boundaries of these zones within a zone mussels and dog whelks determine the lower are not limited by physical factors. Since all in- limits of most intertidal species' life zones. tertidal species are marine organisms, they are Most of these other relationships are much capable of living and thriving underwater for more complex and little understood at this any length of time. time. However, current and future research What are the principal factors creating the should eventually help ecologists understand lower boundaries? In general, they are the more about the zone-determining effects of biological factors of competition and predation. competition and predation in the intertidal A simple example from Maine's rocky intertidal zone. In turn, this may lead to theories that can be applied to more complex environments. 12 FIGURE 6. The salt marsh, just north of Route 1-95 on the Cousins River, Yarmouth. A A.1 14 CHAPTER 2 GENERAL PLANNING CONSIDERATIONS First Steps, Basic Factors Many of the basic facts which are currently Intertidal organisms are, by necessity, a hardy known about the effects of pollutants and cer- lot, adapted to living in an inherently stressful tain coastal activities on intertidal organisms environment. Compared to their subtidal rela- are reviewed briefly in this Chapter, along with tives, they have broad tolerance limits to some related general planning considerations. natural environmental stresses. In general, they Some of the special planning considerations are also more resistant to stresses caused by assocated with specific intertidal environments pollution or other impacts resulting from are described in the following Chapter. human activities. Nonetheless, they are One of the most important steps needed to susceptible to lethal or sub-lethal damage by a properly plan or review developments and other wide range of pollutants and man-made changes. major activities along the coast is to contact Research on the environmental impacts of the appropriate government agencies. Under human activities is being carried out today at an current laws, virtually all projects located in or unprecedented rate, both in the field and in the near intertidal areas require permits from either laboratory. Still, we currently have a very limited municipal or state agencies. Most require both knowledge of how various activities or pollutants town and state permits. Some activities, such will affect a given environment and its inhabi- as dredging, also require approval from federal tants. The need for further research is especially agencies. Thus, planners and developers great with respect to our valuable intertidal en- should be aware of, and carefully follow, all vironments. Though major initial impacts can necessary application procedures. often be predicted with some certainty, more Problems in securing permits can often be subtle sub-lethal of long-term effects are most- avoided if applicants find out about all relevant ly unknown. For example, while scientists pre- legal restrictions as early as possible. (Most of dict the quick deaths of clams smothered by a the pertinent laws and administering agencies heavy coating of oil spilled from a tanker, infor- are listed in Figure 23 of this handbook.) mational gaps make is extremely difficult to pre- Frequently, in addition to reviewing projects dict the effects of chronic "low-level" oil pollu- as part of permitting procedures, state agency tion, or the long-term effects of trace amounts officials can provide technical assistance in of oil on intertidal mud. siting and designing developments or activities 15 so that they will meet existing legal standards. with oil. Also, contrary to popular belief, oil and However, developers should, and usually do, water do mix to a certain extent. In fact, many of hire private consultants to help them design the toxic components in petroleum products their projects. This often provides greater dissolve in water and can kill or harm assurance that projects will be designed con- organisms -that pass oil-polluted water through sistent with municipal, state or federal their respiratory systems. guidelines, and more likely to receive the A particularly significant impact of oil pollu- necessary permits. tion is the destruction of the juvenile forms of Petroleum Hydrocarbons marine species. Larval and juvenile forms alre generally much more sensitive to oil than Maine has taken the lead in responding as a adults. This means that the young, the future state to the threat posed by oil pollution to the generation of a species, can be wiped out by oil coast. Recognizing that, in terms of tonnage, pollution even when the adults survive. As a more crude petroleum and petroleum products result, an investigator reporting that an oil spill are handled by Portland than by any other New had no effects on a clam flat because he dis-, England port, and that oil terminals in Harpswell cove-red adult clams were still present, may and Searsport are supplied by ocean going have overlooked the major catastrophe repre- barges and tankers, landmark legislation pro- sented by the loss of juvenile clams. Frequent- viding for regulation to prevent oil spills and for ly, larval mortality from spills is compounded by effective response to accidents was passed in the fact that oil can remain in fine sediments for 1970. The Hazardous Waste Division of the a period of many years. Although the adult Maine Department of Environmental Protection population may survive and even reproduce maintains emergency standby capabilities and after an oil spill, each new generation of larve contingency plans for swift cleanup measures may die as soon as they enter the contaminated in case spills occur in the high oil traffic areas sediments. Thus, the total population of the such as Casco Bay and Penobscot Bay. species suffers and may decline from a lack of This extensively organized effort to prevent recruitment. and contain major accidents as well as more Non-lethal effects on marine organisms from frequent, smaller oil spills is justified by past oil pollution so far reported include develop- events such as the grounding of the tanker ment of abnormal tissue growths in clams, Northern Gulf in 1963, of the tanker Tamano in dela, ed molting in lobsters, abnormal sexual Y 1972, of the tanker New Concord in 1979, and behavior of fiddler crabs, abnormal develop- the underground pipeline leak at Searsport in ment of barnacle and sea urchin larvae, and dis- 1971. ruption of the sensory mechanisms of lobsters, Interticlal areas are also subject to oil and oily amphipods, and mud snails. Oil destruction of wastes originating from households, industry larval forms and other organisms low on the and motor vehicles and transported by storm food chain may reduce the overally productivity runoff through the drainage systems of coastal of a marine habitat. communities. These incidents underscore the Exposure to wave action and sediment com- belief of many marine scientists that oil pollu- position are the two major factors controlling tion poses the most serious threat facing the in- how much damage an oil spill creates in an in- terticlal habitats of Maine. tertidal area and how long adverse impacts last. Oil can kill or adversely affect marine organ- On high-energy shores, exposed to heavy wave isms in several ways. Following a spill, asphyx- action, oil is often dispersed relatively quickly iation, or death by smothering, is a primary by waves. In low-energy areas protected from cause of mortality in the intertidal zone. Bar- heavy wave action, oil may persist for years. nacles are especially susceptible if the coating Rocky shores are most easily cleaned of oil by of oil is thick enough to be higher than the tops waves, tides, and rain. Cobble beaches and of their shells. A coating of oil on rock surfaces gravel beaches are most easily cleansed than can also cause periwinkles and other species to sand beaches. Sand flats, mud flats, and salt lose their hold on the rocks and be washed marshes are the least easily cleansed habitats. away by the waves. Although residents of coastal towns cannot Many marine species can be poisoned and control tanker traffic offshore, they can become killed quickly if their exposed fleshy parts come familiar with procedures for responding to oil in contact with oil. Deposit-feeding organisms, spills from tankers or other sources by contac- such as marine worms, can be poisoned by in- ting the Department of Environmental Protec- gesting organic materials or sediments coated tion. In terms of general planning considera- 16 tions, they can carefully evaluate the siting, intertidal or subtidal area prevents a normal construction, maintenance, and operation of mature community of marine species from local off-loading or storage facilities for becoming that area's contribution to the sur- petroleum products or any other projects that rounding ecosystem. involve the potential for major or chronic oil Dredging can also change local current pat- pollution problems. terns. Since the type of sediments deposited in an intertidal or subtidal habitat depend largely Dredging on current speed and direction, a change in cur- Dredging is the removal of sediments from rent may lead to a marked change in bottom intertidal, subtidal or wetland habitats. Most sediments. The type of sediments in an area dredging in Maine is done to maintain or open determine, in turn, what kind of plants and up channels of navigation. Less frequently, animals can live there. As a result, current dredging is undertaken to obtain sand, shell or alterations caused by dredging can lead to gravel deposits, or to prepare a coastal site for significant changes in the types of plants and construction. Whenever dredging is planned for animals found in and around a dredged area. It any purpose, the potential effects on marine en- may, for example, reduce the amount of clams vironments in the vicinity must be carefully available for commercial harvesting by chang- analyzed as part of the permitting process. ing the character of local mudflats. The basic methods used in dredging are A common effect of dredging is increased mechanical and hydraulic. In mechanical dredg- water turbidity. During dredging operations, ing a crane with a large bucket loader or a large quantities of mud and silt are stirred up power shovel is used to remove sediments. The into the water. This underwater cloud of sedi- sediments, referred to as "spoil", are dumped ments can reduce the survival rate of tiny shell- overboard or onto a barge that transports its fish larvae and juvenile fish that live in the water loads to a disposal site. Hydraulic dredging in- column. As it resettles it may smother or foul the volves the use of powerful pipeline dredges respiratory organs of clams, mussels, and other that suck up the sediments and transport them species. The extent of the turbidity depends on by suction pipe to a disposal site. In Maine, the type of sediments being dredged, the dredg- mechanical dredges are usually employed due ing method used and local water currents. The to the relatively coarse nature and low volume effects may be short-term and localized in some of the materials dredged here. cases. In others, the distrubed silt may be resus- Dredge spoil along our coast generally con- pended again and again by tidal and wind-driven sists of sand, soft mud and small amounts of currents and adverse effects from the turbidity rocks. The areas most frequently dredged in may occur up to a half-mile from the dredging Maine during the past twenty years are Portland site. Harbor, the Kennebec River, the Penobscot Turbidity can also decrease the penetration River, Rockland Harbor and the Royal River. of light through the water, thereby reducing the (A list of recent dredging locations and disposal growth of floating planktonic or attached plants sites is given in Table 11, p. 57, Data and upon which other organisms feed. This Analysis for the NE/L1 NERBC "Dredging phenomenon is generally not very significant in Management: Sound Region", 1981.) interticlal areas, but it is of special concern in Dredging involves environmental impacts deeper water, where light penetration may that should be carefully considered. These im- already be low. pacts result both from the removal of When turbidity does seriously impair plant sediments and from their disposal. Dredging photosynthesis, the dissolved oxygen levels in removes bottom-dwelling plants and animals a marine habitat may be reduced, an effect that along with the sediments. Indeed, newly- may be made even worse as bacteria use up dredged areas tend to be virtually devoid of life oxygen to decompose suspended organic sedi- and their physical and chemical properties are ments. Low levels of dissolved oxygen have often very different from natural habitats. In sometimes lead to massive kills of marine in- time, dredged areas can be recolonized by vertebrates around dredge sites. marine organisms, but they are generally less When dredging occurs in a polluted area, it can productive than they were before the dredging release poisonous hydrocarbons, toxic heavy occurred. In addition, dredging tends to create metals and oxygen-depleting organic materials an unstable sediment configuration on the bot- that were bound up in the bottom sediments. tom that leads to fast sediment build-up requir- Plants and animals which absorb, ingest or ing further dredging. Repeated dredging in an come in contact with the chemicals and metals 17 can be injured or killed. And, as explained, tion, bulkheads, seawalls and piers can change decomposition of organic materials released by local current patterns in ways that often cause dredging can lower dissolved oxygen to levels scouring of surrounding sediments. This can lethal to many species. lead to severe erosion or alteration of the bot- The disposal of dredge soil is not usually a tom sediments and thus affect resident plants major problem in the intertidal zone, since it is and animals. In Maine, direct and indirect loss commonly dumped at sea. However, in some in- of interticlal habitats due to pier and wharf con- stances, spoil has been deposited in salt mar- struction is most notable in developed harbors shes, smothering and drastically decreasing such as Portland, Boothbay Harbor, Rockland the productivity of these important intertidal and Eastport, where relatively large interticlal environments. Many of our commercially impor- areas are covered by such structures. tant shellfish and fish species spend part of A further effect of piers and wharves may be, their life cycle in a salt marsh habitat. Thus, decreased productivity of plant and animal dumping dredge spoil on salt marshes is con- communities due to shading. The decreased sidered a serious environmental problem and is availability of sunlight under piers and wharves not a recommended practice. In addition to the is believed to reduce the growth of the tiny loss of habitat from a smothering layer of spoil, plants, called phytoplanktan, that live in the dredging in or near a marsh can lead to changes water column and the even more productive in the tidal flushing rate that may cause erosion plant communities that live on the bottom sedi- and slumping of marsh banks. ments. In turn, this may depress local popula- The U.S. Army Corps of Engineers, which tions of the shel If ish and fish that feed on these regulates dredging, has recently been conduc- plants. ting research to determine the feasibility of For planners and developers, two general creating or reestablishing marshes on dredge areas of consideration should be addressed spoil sites. Under certain conditions, the with respect to construction along or near the marsh-buildings techniques being developed coast. First, the potential short and long term by the Corps may allow spoil disposal on effects of the project on intertidal, subtidal and marshes to become an acceptable option other environments should be thoroughly in- where other methods are more expensive. Also, vestigated with the assistance of relevant pro- "beach nourishment", aimed at replacing sand fessionals. Secondly, construction methods lost from eroding beaches, is possible with should be planned and carried out in ways that suitable spoil materials. will minimize erosion and any other impacts that could be avoided through careful fore- Construction thought. Construction activities - the building of Shipping and Boating homes, walls, piers, jetties, dams, industrial or commercial facilities, roads, parking lots, Ship and boat traffic and their on- and off- bridges, walkways and other structures - can loading can affect intertidal and shallow sub- affect nearby intertidal environments in several tidal zones, directly or indirectly, in a variety Of ways. The most common problems are habitat ways. One direct effect may be shoreline and destruction and increased turbidity. Such pro- bottom sediment erosion caused by the wakes blems can occur as a result of preparatory of passing vessels. A more pervasive problem dredging or when erosion on the construction is that boats and ships powered by petroleum site releases a heavy load of sediments that fuels comprise a significant source of chronic runs off into adjacent interticlal areas. The ef- oil pollution along our coast. For example,, fects of turbidity caused by erosion are similar research indicates up to one-third of the fuel us- to those caused by dredging (see preceeding ed in outboard motors ends up in the water, and section). These adverse effects are normally of that this so-called exhaust water is toxic to short duration as long as the construction does many marine species. In addition, boats and not alter local current patterns or flushing rates ships require the loading of fuel in the intertidal and erosion is not a persistent problem. zone. Despite stringent precaution, seeps and In contrast, bulkhead and pier construction spills are a common occurrence during fueling or other developments actually sited wholly or operations. Oil tankers' spills and flushing pro- partially within the interticlal zone can have cedUres are another source of oil pollution long-lasting impacts. Most obvious is the direct along our coast. The varied effects of these are loss of the potentially productive interticlal discussed in more detail above in the habitats displaced by the development. In addi- "Petroleum Hydrocarbons" section. 18 Shipping activity also commonly results in posed to them. A few species low on the food the release of human excrement, garbage, and chain are particularly sensitive to biocide con- other organic wastes into coastal waters. This tamination. Most notably, lobsters and other can be a significant problem where there is ex- crustaceans, which are in the same taxonomic tensive commercial boat traffic, such as in Port- group as insects, may be harmed or killed by ex- land Harbor or in confined harbors - especially tremely low concentrations of pesticides. during the summer when small boat and Recent technology has lead to the develop- pleasure craft traffic is heavy. ment of biocides that are not as long-lasting in Like untreated municipal sewage, extensive the environment as DDT and some other quantities of human wastes from boats can in- formerly popular agricultural chemicals. crease the threat of disease and prevent the However, before the use of any blocide in or harvesting of otherwise productive clam flats or near the seashore or any stream or river enter- even making swimming a dangerous proposi- ing it takes place, investigation should be made tion. Spills of toxic substances may also occa- into potential effects on intertidal organisms as sionally occur as a result of shipping activities. well as upon coastal residents. In addition to Normal maintenance activities, such as scraping, the site of spraying, attention should be given cleaning, and painting may lead to the release to concentrations used and methods of applica- of certain other types of pollutants that are harm- tion. Furthermore, it should be remembered ful to marine organisms. that most uses of biocides are controlled by Perhaps the most notable indirect effects state and federal regulations and that many ship and boat traffic have on intertidal environ- uses require appropriate permits. ments occur as a result of the construction of support facilities piers, wharves, marinas, Heavy Metals bulkheads, etc. which may destroy or The group of pollutants called heavy metals adversely impact surrounding intertidal includes lead, mercury, chromium, manganese, habitats. Obviously, a major planning con- nickel, copper, zinc, arsenic, cadmium, silver sideration with respect to boating and shipping and vanadium. Very small "trace" amounts of is the location of these support facilities. these metals occur naturally in soil, fresh Whenever possible, they should be sited in water, and seawater. But, when the level of a locations that minimize short and long term en- heavy metal becomes unnaturally high in an en- vironmental effects. vironment, it can have adverse or even lethal ef- fects on resident species - including humans. Biocides (Pesticides, Herbicides and Fungicides) Pollution by heavy metal is most often a result of industrial discharges. In Maine, for ex- "Biocide" is a general term that can be used ample, relatively high levels of certain heavy to refer to any of a variety of chemicals used in metals have been found in the water and sedi- agriculture and forestry to control pests and ments in or near the discharge areas of some diseases. These include: pesticides used to pulp and paper mills, tanneries, municipal control destructive insects and animals; herbi- sewage treatment plants and mining sites. The cides used to control weed plants; and, fungi- concentration at which toxicity occurs varies cides used to inhibit fungus growth on crops. with each metal and each species. When biocides are introduced into the intertidal In general, heavy metals tend to build up in zone or any other environment by accident or the body tissues of animals, resulting in the purposefully, there is often the potential for same kind of "biomagnif !cation" noted for adverse effects on non-target plants and pesticides - that is, the higher an organism is animals or people. up the food chain in an environment polluted by Effects can vary greatly from species to metals, the greater the concentration of the species, depending on the type and concentra- pollutants in its tissues and the greater the tion of the biocide. Species high on a food possibility of adverse physiological effects. chain are often most susceptible to severe ef- Depending on the species, the metal in ques- fects due to biornagnification or increasing tion, and its concentration, those effects can in- build-up, of the chemicals in the tissues of clude behavioral disorders, genetic defects, higher organisms. Examples can be seen in the disruption of organ functions, or death. The ma- fish and bird kills that have occurred as a result jor concern into the intertidal zone is the poten- of pesticide use over the years. tial effect on the health of people who might eat Intertidal invertebrates and other lower organ- contaminated clams, mussels, or other inter- isms may ingest or absorb biocides when ex- tidal organisms. Since heavy metals can be ac- 19 cumulated in the body, a person eating enough sediments to maintain their sand supply. contaminated shellfish or fish may develop Though tidal power projects are still in the heavy metal poisoning. future on our coast, some researchers have Current state and federal regulations limit already become concerned about the possible the concentration of heavy metals allowed in in- environmental side-effects of damming coastal dustrial effluents as well as in fish and shellfish bays. Existing tidal projects in other countries sold commercially. Thus, when the siting of in- and preliminary impact studies of planned tidal dustrial development or mining along the coast schemes indicate that tidal impoundment may is considered, the potential for heavy metal significantly alter tidal range, current flow, pollution of local intertidal environments water temperature, wave action, sedimentation should be investigated. Monitoring of heavy and erosion patterns and other factors in and ' metal concentrations in intertidal environments around a dammed bay. These changes, in turn near existing industrial discharge areas may may adversely effect the plants and animals also be a wise precaution. Another possible For example, under most conditions, a tidal pro- source of heavy metal pollutants is a sanitary ject would be expected to shrink the tidal range landfill, from which metals may leach into sur- within a dammed bay, thus reducing the habitat rounding waterways. Recently, some scientists available for clams, mussels, and other valuable have also become concerned that under some intertidal species. circumstances "acid rain", caused by sulfur Impoundment might also be expected to de- dioxide and nitrogen oxide pollution from coal crease the flushing rate of a bay, preventing the and oil-fired power plants, factories and organisms within from receiving as much food automobiles, may leach heavy metals from the and oxygen as previously and allowing a possi- soil, thus releasing them into water bodies. ble harmful build-up of waste products to oc- cur. In the case of large tidal projects, adverse Dams impacts resulting from changes in tidal range Damming or otherwise impounding a river may also occur outside of impounded bays in mouth for conventional hydropower, or dam- intertidal areas for many miles around. ming a bay for tidal power can have major ef- Toxic Substances and Hazardous Wastes fects on local intertidal environments. These ef- fects may be deemed an acceptable trade-off in Although incidents such as those at Love the final analysis of a specific dam project. Canal, New York and East Gray, Maine have However, they must at least be investigated and made us all more aware of the threat to people considered in order to receive the necessary from hazardous wastes and toxic substances, state or federal permits. Current regulations we may sometimes forget that poisonous exist in part to ensure that the benefits of a dam chemicals also pose a threat to other living outweigh its adverse environmental impacts. species. Maine industries use hundreds of dif- The potential impacts of a conventional dam ferent chemicals and produce hundreds of nearthe mouth of a riveron nearby intertidal en- thousands of gallons of hazardous wastes each vironments such as the salt marshes and mud year. State regulations now require "cradle-to- flats in river-mouth estuaries include altera- grave" accounting for all toxic substances. tions in the volume and flow of freshwater and There are also regulations regarding the use, subsequent changes in salinity, sedimentation transportation and disposal of most of these rates, circulation patterns of the water, temper- chemicals. For example, it is now illegal to ature, shoreline erosion, nutrient levels and dispose of hazardous wastes of any kind in a other crucial factors. town sanitary landfill. Town and industry plan- Such changes in the chemistry and flow of ners on the coast, as elsewhere, must consider the water and the stability of the geological these things in planning or undertaking any ac- substrate may have major effects on the resi- tivity dealing with toxic substances and hazard- dent communities of plants and animals. Small ous wastes. variations determine what types of crustaceans, If poisonous industrial chemicals do pollute shellfish, fish, plants and other species can sur- an area of the intertidal zone, the effects will de- vive and reproduce in a given environment. pend on many factors: the type and quantity of Where impoundments alter downstream sedi- the chemicals, the geology and hydrography of ment flow and act as settling basins, they may the site, the type of organisms in the polluted also contribute to gradual erosion of nearby area, and so forth. Effects could range from beaches or other geological environments that minimal to disastrously lethal. Suffice it to say may have depended on the former influx of that toxic substances and hazardous wastes' 20 should be properly used and disposed of at all Where substantial mortalities occur among times, and every attempt should be made to juveniles, and where adults have been over- keep them out of the i ntertidal zone or any other harvested, the abundance of affected species natural environment. will decline and the flats will be less productive. Extreme overharvesting can effectively eliminate Recreational Activities populations of clams and worms sought by Recreational use of the intertidal zone is both the recreational and commercial diggers. commonly concentrated on sandy beaches. Thus, coastal town officers should, and often This is an environment of relatively limited oc- do, monitor and regulate clam harvesting on currence in Maine, which has only about 30 local flats. miles of large, open, easily accessible beaches, Thermal Effects primarily located along the southwestern half of the state's coastline. Numerous small barrier Power plants, factories and other industrial and pocket beaches are scattered among the in- operations located on the coast sometimes lets and islands making up irregular 4,000 mile release discharges into intertidal areas that are shoreline in Maine, but these are generally far warmer or cooler than the ocean temperatures. less accessible than the larger beaches. In some cases, warm-water discharges free of Beaches themselves are high-energy toxic pollutants may enhance the prospects for dynamic environments well able to stand the aquaculture ("fish farming") within the impact of many users. On the other hand, the discharge area. Along much of Maine's coast, dunes lying landward of many beaches are very for example, oysters can only be raised suc- fragile elements of interdependent dune-beach cessfully where ocean temperatures are made systems. Even unregulated foot traffic, by higher than normal by warm-water discharges destroying beach grass, can lead to significant or impounding. Salmon culture may also be dune erosion. This can lead, in turn, to disrup- much improved in discharge-warmed waters. tion of the dune-beach sand cycle and hence to However, many other resident intertidal erosion of the beach proper. Similarly, off-road species cannot survive any significant warming vehicle traffic, construction and other distur- or cooling of the waters beyond that which bances of dunes can have secondary adverse takes place naturally. impacts on beaches. Heating the water is the most common and Gravel, cobble and boulder beaches are not potentially the most serious thermal effect of nearly as popular for recreational activities as industrial discharges. Many native species in a sandy beaches, though most common types of heated area may not be able to survive, recreation would have little impact on them. especially those who were already living near Some sand flats and mud flats are used for the the southern extreme of their range. In general, recreational digging of clams. However, this ac- the effects are even more serious in subtidal tivity rarely reaches the intensity of commercial environments, because subtidal organisms clam or worm-digging efforts. tend to have less tolerance to thermal changes Although rocky shores and marshes are not than intertidal plants and animals. as popular as our large beaches for recreation, The effects of cooled water, such as might heavy use at places of general public access exist around a liquified natural gas (LNG) plant, can sometimes be a problem. For example, ex- are not well known. The most significant may cessive collecting can reduce the populations be that the temperatures needed for spawning of organisms living in tide pools and other inter- of some species would no longer be reached. tidal habitats. This is why permits are required Whenever industrial discharges, thermal or to collect intertidal plants and animals in na- otherwise, are to be released into interticial tional parks. areas, appropriate state or federal permits must Commercial Digging of Clams and Worms be sought. This permit process makes it necessary to investigate the potential for Where extensive digging takes place for adverse effects on intertidal environments. clams and marine worms, large portions of the surface mud and sand flats may be overturned. Sewage and Organic Wastes This exposes many burrowing intertidal organ- isms not gathered by the diggers, including In recent decades significant progress has juvenile clams and worms, to stresses they may been made toward reducing pollution from not be able to tolerate - the summer sun, rain, sewage and organic wastes in Maine..However, winter cold, etc. untreated municipal wastes, organic industrial 21 effluents, and domestic sewage wastes from in- organisms. Furthermore, in the area near a dividual homes are still a serious problem in sewage or industrial outfall, wastes may some- some coastal areas. Potential effects on human times be great enough to actually smother health and marine organisms as well as current plants and animals living on the bottom sedi- laws and regulations make it necessary to ments. thoroughly investigate the environmental and Ironically, treatment of sewage wastes rnay legal consequences whenever such pollution sometimes create the potential for other pro-, may occur. blems. For example, many Municipal and in- In terms of human health, the primary threat dividual Sewage treatment processes use is from the dangerous diseases that are chlorine to kill disease - causing bacteria. But associated with untreated sewage. Sewage chlorine is very toxic to many organisms other pollution also has effects on Maine's economy. than bacteria and improper management of In an area where untreated wastes are substan- chlorine treatment has occasionally resulted in tial, commercial and recreational clamming major fish kills. It is possible that chlorine treat- must often be prohibited due to the threat of ment may have impacts on other marine organ- disease. Currently, about one-fifth of all Maine isms as well, though at present little is known, clam flats are closed to harvesting due to about these effects. sewage contamination. The effluent from sewage treatment plants One possible impact of sewage disposal and may also contain oil and other hydrocarbons, organic pollution on intertidal organisms is ex- toxic chemicals and heavy metals, since most cessive nutrient enrichment of the water col- existing treatment plants lack the technology umn. This can result in heavy "blooms" of to remove such pollutants. These pollutants planktonic plants and algae. As these plants normally pass through the plant unaltered into grow and decompose, the level of dissolved the environment and may have adverse impacts oxygen in watercan fall drastically, causing die- on the species in and near the discharge area. offs of fish and other species. Serious lack of Similarly, the outflow from storm sewers can oxygen can also result as bacteria decompose have effects on intertidal organisms. These human wastes, pulp and paper mill wastes, and sewers carry rain water and meltwater from other organic wastes that may be dumped in roads and parking lots either into treatment the intertidal zone. When the bacteria bio- plants or directly into a nearby body of water. degrade these wastes, they use up substantial Frequently, the runoff is not as pure as the amounts of the dissolved oxygen in the water. driven snow or rain that it once was. In passing As in the case of algal blooms, this can harm or over roads, parking lots, and other developed kill fish, marine invertebrates and other aquatic acreage, the water may carry with it silt, oil and various toxic chemicals. 22 FIGURE 7. The sand beach at Reid State Park, Georgetown. xp, "."tow 7r A t MW' oil 24 CHAPTER 3 MAINE'S INTERTIDAL ENVIRONMENTS A Closer Look Within Maine's 4,000 mile-long intertidal zone, Soils maps are often used in regional or town there are a number of unique communities of planning for purposes such as locating areas plants and animals, each adapted to the suitable for subsurface sewage disposal or physical conditions of different kinds of sanitary landfill sites and for identifying prime habitats. A sand beach is home to a collection agricultural land. The Marine Environments of animals far different than those in a salt maps can also be helpful for this kind of marsh. To understand the effects of human ac- generalized planning. In addition, because of tivities on intertidal organisms it is necessary their larger scale they can be used for more to know something about the environmental detailed planning and environment impact characteristics of each basic type of intertidal assessment. habitat. Basically, the Marine Environments maps in- As explained in the companion volume to dicate the size and location of individual this handbook, Geology of Maine's Coast, it is geological environments, or "units", (a beach, a also important to understand that coastal en- mudflat, a tidal channel, etc.) as they occur vironments are often linked together as part of along the Maine coast. Altogether 109 maps complex geological systems and that changes have been produced, covering land along the in one environment can have impacts on others state's entire coastline between the nearshore nearby. In the Geology of Maine's Coast, the uplands and shallow subtidal depths. On them, Maine shoreline is described from a geological 55 different types of marine environments are perspective based on the 55 types of geologic distinguished with simple letter codes. environments catalogued on the Coastal To coastal residents, the most fundamental Marine Geologic Environments Maps use of the maps is to determine the geological developed by Maine's Coastal Program. characteristics of particular sites in their town. These maps are not difficult to understand. In Though verification by on-site inspection a number of ways, they are similar to the Soil should always precede any important decision, Conservation Service soil maps with which a quick look at the appropriate map will show in most land use planners are already familiar. advance, with reasonable accuracy, what kind 25 FIGURE 8. Marine Geologic Environment Map and Legend MAP SYMBOL GEOLOGIC ENVIRONMENT SUPRATIDAL ENVIRONMENTS U Tidal Creeks Sd Dunes & Vegetated Beach Ridges Sw Fresh-Brackish Water Sm Fresh-Brackish Marsh Marsh Drainage Ditch Sz Man-Made Land Sx Landslide Excavation & Deposits INTERTIDAL ENVIRONMENTS Unit Boundary Marsh Environments M1 High Salt Marsh M2 Low Salt Marsh Approximate Unit-Boundary M3 Marsh Levee M4 Salt Pannes & Salt Ponds Beaches Approximate Transition Boundary Between 131 Sand Beach Estuarine and Marine (30 ppt salinity) B2 Mixed Sand & Gravel Beach Waters and between Estuarine and River B3 Gravel Beach (0.5 ppt salinity) Waters. B4 Boulder Beach B5 Low-Energy Beach Br Boulder Ramps Bw Washover Fan Ac Bs Spits Ci Flat Environments F Mud Flats F1 Coarse-Grained Flat F2 Seaweed-Covered Coarse Flat F3 Mussel Bar hf F4 Channel Levee F5 Algal Flats F6 Veneered Ramp Miscellaneous Environments M Ledge Mc Fluvial-Estuarine Channel Mp Point or Lateral Bars Ms Swash Bars Mf Flood-Tidal Delta Me Ebb-Tidal Delta Mb Fan Delta A/ Md Spillover Lobe lie )OC/ SUBTIDAL ENVIRONMENTS 9.6 Flat Environments Fm Mud Flat Fc Coarse-Grained Flat Fe Eelgrass Flat Cz Fs Seaweed Community 101* Fb Upper Shoreface Sl A* Fp Lower Shoreface Channel Ehvironments Af C1 High-Velocity Tidal Channel C2 Medium-Velocity Tidal Channel C3 Low-Velocity Tidal Channel C4 Estuarine Channel C5 Estuarine Flood Channel C6 Estuarine Ebb Channel C7 Inlet Channel C8 Dredged Channel Cs Channel Slope 26 of environment exists at any given spot in the assessment, however, should take into con- shoreland zone. It will show, for example, sideration the fact that the connections bet- whether a certain intertidal area is a "coarse- ween human activities and marine environ- grained mudflat" or a "seaweed covered flat". ments are extremely complex and that the links The pinpointing and identification of these between the living and non-living components distinct environments is especially advan- of those environments are equally intricate. tageous to developers, town planners, in- The purpose of this chapter is to expand on dustrial researchers, and other people for the information found in the Geology of resource utilization planning. For instance, by Maine's Coast handbook and enhance the using the maps, efforts to locate suitable sites usefulness of the Marine Environments maps for piers, houses, commercial facilities, in- by providing ecological descriptions of in- dustrial plants and other developments are dividual intertidal habitats. Using this informa- made much easier. Places where unstable soils tion and the appropriate maps, planners and or other geological conditions make a project developers can get a good general idea of what unfeasible can be quickly identified and ruled species might be living in a particular intertidal out. The proximity of sensitive, ecologically location. Knowing this, they can then draw valuable environments to a site can be noted. some preliminary conclusions about the poten- In addition, the possibilities for expanding a pro- tial biological impacts of a project or activity ject in the future can be estimated by looking at proposed for that location. It is necessary to the locations, sizes, and nature of the environ- remember that these conclusions would be ap- ments in the area. proximations. There is no substitute for actual Similarly, the detailed information on the on-site studies. Nonetheless, they can be ex- Marine Environments maps can facilitate the tremely helpful and may save considerable time location of potential aquaculture sites, com- during the early planning stages and prelimi- mercially harvestable mussel or seaweed beds, nary evaluation of coastal projects. and other marine resources. It can help in To provide reliable information about Maine's creating effective strategies to combat shore- intertidal habitats, extensive studies have been line erosion problems, or in the development of undertaken by researchers from the Bigelow zoning guidelines. Recently, the maps have Laboratory for Ocean Sciences, headquartered been used to help formulate the clean-up plans at McKown Point in West Boothbay Harbor. that would be implemented in case of a major- These researchers carefully analyzed the kinds, oil spill off Maine's coast. numbers, and diversity of species found at Because the differences between individual sampling sites located in various intertidal sites are also crucial in determining the effects habitats up and down the coast. an activity or project may have on the environ- For purposes of study, the researchers defin- ment, another basic use of these maps is for en- ed nine basic intertidal habitats common to vironmental impact assessment. While in many Maine. Because they used an ecological, rather cases professional advice is needed to under- than a geological viewpoint, these habitats are take this type of analysis, it is possible - and not quite the same as the units defined on the often necessary - for laymen to make judge- Marine Environments maps and the companion ments about potential environmental impacts geology handbook. However, there is a very for themselves. close correlation and the relationships of the Members of municipal planning boards, for two systems of classification are indicated in example, spend considerable time reviewing the following section to allow coordinated use developments proposed for their towns, a pro- of all three information resources. cess that usually involves some kind of environ- Sand Beach Habitats mental impact assessment. For their part, developers generally have to study and report Description: Sand beach habitats are made up the potential environmental effects of their pro- primarily of well sorted, sand-sized particles. jects in order to get needed permits and fulfill They are generally high-energy environments, application requirements. greatly exposed to the battering of waves. The As a rule, the sophistication of impact degree of exposure for a particular sand beach assessments varies with the size or expected depends on the direction the beach is facing environmental influence of the project in ques- and how much protection is provided by nearby tion, ranging from simple common sense judge- islands, headlands, or other features of the ments to highly involved computerized simula- local topography. Most of Maine's relatively tions and technical studies. Any type of impact limited extent of sand beaches occurs in the 27 area between Kittery and Cape Elizabeth. This have little effect on sand beaches. On the other so-called Arcuate Bay region is characterized hand, Pollution by oil or toxic wastes can have by long stretches of sand beach separated by major adverse impacts on beach animals. So, rocky promontories. East of Cape Elizabeth, too, can construction on or near a beach., sand beaches are much more scarce. Major In terms of planning considerations, it is ex- beaches are found east of Casco Bay at Reid tremely important to remember that beaches State Park and Popham. There are also are part of interconnected beach systems, numerous small pocket and barrier beaches which usually include dunes on the landward scattered among islands and peninsulas along side and sand flats on the seaward margins. the eastern portion of our coast. Well known ex- Alterations of the other parts of this system can amples are Sand Beach in Acadia National Park affect the beaches as well. and the beach at Roque Bluffs State Park. Immediately behind sand beaches, where there are sand dune areas, residential or com- Biological Characteristics: The constant mercial development can disrupt the natural movement of the particles on sand beaches cyclical transport of sand between beaches and which results from exposure to heavy wave ac- dunes, thus threatening the whole system with tion allows only very specialized intertidal sediment "starvation". Devegetation and sub- creatures to live in these habitats. In fact, sequent erosion of adjacent dune fields can studies indicate that, in an area of a given size, also contribute to any erosion problems occur- the number of different species and the total ring on nearby sand beaches. Stocks of sand number of individual resident organisms is eroded from the dunes may be lost permanently usually lower on sand beaches than any other from the whole beach system. basic type of intertidal habitat. This is an indica- Seawalls or other shoreline structures built tion that sand beaches are harsh environments to protect beachfront property are sometimes a in which to live. The sand grains are continually threat to beach habitats. Such structures often being shifted by waves, and there is no solid accelerate erosion on beaches by causing ex- substrate suitable for the attachment of cessive wave scouring, or removal of sand, from animals or plants. Thus, any sand-dwelling in front of the seawalls during storms. Seawalls organism must be able to shift or reestablish its also tend to increase loss of sediments from "home" frequently. adjacent areas at ends of the structures. There are some species that have adapted to Beaches that depend upon riverborne sedi- this disruptive style of life. Most common and ments as a source of sand may be adversely im- abundant are amphipods, the shrimplike crusta- pacted by structures such as jetties or up- ceans known to many beach-goers as "beach stream dams which divert or retain critical sand fleas". Also relatively abundant on sand beaches supplies into new locations. are various kinds of burrowing marine worms. Structures located directly in the intertidal various kinds of burrowing marine worms. area can prevent the transport of sand by Other species commonly found on sand waves, tides and currents between offshore beaches include various marine isopods and deposits and beaches. This contributes to loss certain insect larvae and adults. of beach habitat by diminishing the natural Importance: Because there are relatively low replenishment of sand during the beach concentrations of sand worms and other com- system's annual cycle. mercially valuable intertidal species on sand An important consideration with respect to beaches, these habitats have relatively low sand beach system is their tendency to migrate direct economic importance to Maine's marine landward over time. Beaches are very mobile fisheries industry. Storms do sometimes wash environments and their location along -the surf clams to lower beach areas in Southern shoreline is largely controlled by sea levels. Maine and these are occasionally harvested. Since the last great Ice Age, sea levels in Maine However, sand beaches are very valuable and and worldwide have been rising steadily. This popular for their recreational potential. In addi- rise "pushes" sand beaches and the dunes tion, sanderlings, sand pipers and many other behind them gradually inland. The rate of this shorebirds depend on beach amphipods as a retreat varies greatly along our coast depending major food source. on such factors as shoreline slope, shoreline configuration, and general location of the Planning Considerations: Foot traffic, surf coastline. Some level of shoreline recession is fishing, swimming, sand castle building and inevitable on all beach systems, however, and most other common activities of beach-goers any buildings or other developments on or near 28 beaches should be located a considerable FIGURE 9. A large sand flat at the head of distance behind the current high water mark to Bailey's Mistake in Trescott. prevent future flood or storm damage. Recent state and federal regulations have in- creasingly restricted development along beaches. State and federal agencies have also determined rates of shoreline recession for various local areas of our coastline. This infor- mation and other government construction guidelines can help planners and developers design and locate projects near beaches ap- propriately. A Geological Units Included: SAND BEACHES Map Legend - B 1 Color - Lemon Yellow Percentage of Total Cost Area Mapped - 1.00% SPITS Map Legend - B s Color - Gold Percentage of Total Coast Area Mapped - 0.04% MIXED SAND AND GRAVEL BEACHES (in part) found at the southern end of Reid State Park, Map Legend - B2 and behind Wells Beach, Thompson Point Color - Yellow Orange Beach, Old Orchard Beach and Ogunquit Percentage of Total Coast Area Mapped Beach. Often, the upland extent of these small - 1.50% sand flats is salt marsh. Sand Flat Habitats Biological Characteristics; Because they are Description: Sand flats might be viewed as protected from heavy wave exposure by local the low-energy counterpart of sand beaches. topography, sand flats are much less harsh as Though composed primarily of sand, these environments than sand beaches. This allows a habitats are located in areas more protected greater variety of animals to live in these from wave exposure than sand beaches. Thus, habitats. In fact, the diversity of species of sand they have a greater diversity of sediment parti- flats is second only to that on mud flats. cle types, including various percentages of silt, However, like sand beaches, the total produc- clay and organic detritus. These habitats tivity of sand flats is rather low in terms of the generally have a slight slope and can be number of individual organisms found per distinguished from mud flats by particle com- square meter. Various types of marine worms position and the sand ripples generally ex- and amphipod crustaceans make up the most hibited on their surfaces. Although low-energy abundant groups of species that live on sand intertidal flats south of Maine are commonly flats. Soft-shelled clams are usually fairly com- composed of sand, the number of large sand mon. In areas where the flat is composed of flats in this state is rather limited. Here, par- large percentages of silt, the Baltic clam and ticularly east of Cape Elizabeth, most of the other species more typical of mud flats may source material for low-energy environments is also be common. Moon snails, green crabs and silt and clay, which results in the extensive mud other clam predators are often found on sand flats found along our coast. The major sand flat flats where their food supply exists. areas in Maine are at Sagadahoc Bay and Heal Importance: Though not as productive as mud Eddy in Georgetown, Gerrish Island in Kittery, flats, sand flats do provide significant habitat Bailey's Mistake in Trescott and Clam Cove in for clams, marine worms and other commercial- Rockport. Other less extensive areas of sand ly havested species. Resident species also flats occur behind some beaches where small comprise a food source as well as for various streams empty into the ocean. Such places are species of waterfowl and shorebirds. 29 Planning Considerations: Most animal resi- Mud Flat Habitats dents in sand flats are highly sensitive to pollu- Description: Mud flats are fine-grained tion by oil and toxic chemicals. Sand flat com- habitats found in coves, inlets and other pro- munities may also be destroyed or harmed by tected, low-energy coastal sites. The sediments, dredging or filling on or near the flats. Among which include various proportions of silt, clay, the common impacts that are related to these sand and organic material, are relatively stable. activities are direct removal of habitat or Being shielded from heavy wave exposure, they smothering of habitats by dredge spoil. Dredg- are not greatly shifted or disturbed by wave ac- ing, agricultural or construction activities on tion or the daily movements of the tides. Mud nearby environments can also release heavy flats usually have only a very slight grade and metals or chemicals toxic to sand flat organ- are anoxic (lacking in oxygen) just below the isms. In addition, the commercial usefulness of surface. These familiar habitats are a dominant sand flats can be destroyed by sewage con- intertidal environment along the coast of tamination. Maine, in terms of area, and second in linear ex- tent only to rocky shores. In fact, most pro- tected coves, salt marsh borders and other low- energy intertidal areas east of Cape Elizabeth Geological Units Included: drain to expose mud flats. When one looks, at a map of Maine's irregular coastline, it is obvious COARSE-GRAINED FLAT (intertidal) that there are numerous protected areas likely Map Legend - F1 to harbor mud flats. The mid-coast area bet- Color - Dark Brown ween Casco Bay and Port Clyde is particularly Percentage of Total Coast Area Mapped irregular. As would be expected, mud flats here -4.70% are numerous and extensive. Mud flats are also FLOOD TIDAL DELTAS extensive down east in Hancock and Washing- Map Legend - Mf ton counties, where the large tidal ranges often Color - Flesh create flats of great width. Percentage of Total Coast Area Mapped Biological Characteristics: Biologically, mud - 0.03% flats are one of the most productive coastal FAN DELTAS habitats. The diversity of species is higher than Map Legend - Mb in any other intertidal habitat. The average nUrn- Color - Tuscan Red berof organisms found per square meter is phe- Percentage of Total Coast Area Mapped nomenal. (Only boulder beaches and high- - 0.01% eneri y rocky shores host more.) At some mud g CHANNEL LEVEES flat research sampling stations, over 24,000 Map Legend - F4 marine worms, 23,000 gem clams, and 16,000 Color - Cold Dark Grey Hydrobia snails were found in one square meter Percentage of Total Coast Area Mapped of the rich mud. Marine worms and many other -0.01% common mud flat animals are relatively seden- SEAWEED-COVERED COARSE-GRAINED tary, often living in tube houses in the mud, FLATS feeding mainly on organic detritus. This is call- Map Legend - F2 ed deposit feeding. Other common residents of. Color - Light Green mud flats, such as soft shelled clams, feed on Percentage of Total Coast Area Mapped small plants (phytoplankton) and animals (zoo- - 1.00% plankton) they filter out of the water column. This is called suspension or filter feeding. EBB-TIDAL DELTAS Among the most abundant species found in Map Legend - Me mud flats are various types of marine worms (in- Color - Flesh cluding the valuable bait species called blood- Percentage of Total Coast Area Mapped worms and sand worms), soft shelled clams, - 0.03% Baltic clams, gem clams, mud snails and other VEGETATED POINT OR LATERAL BARS gastropods, and various small amphipods (mud Map Legend - My dwelling relatives of the "sand fleas" found on Color - Dark Green beaches). Percentage of Total Coast Area Mapped Here and there on mud flats, one often finds - 0.01% mussel bars, dense accumulations of blue 30 mussels which form a sort of living reef. The shellfish beds and introduce into the water number of mussel bars on a flat tends to vary heavy metals and chemicals that are toxic to from year to year due to frequent destruction by clams, marine worms and other mud flat storm waves or ice. When severe storms hit species. Maine, there may be a significant, though tem- Geological Units included: porary, reduction in the total number of mussel bars along the entire coast. During periods when MUD FLATS (Intertidal) water temperatures are warm and wave action Map Legend - F slight, mussell bar formation is stimulated. Color - Dark Brown Percentage of Total Coast Area Mapped Importance: Mud flats are highly productive - 27.00% both biologically and economically. Each year ALGAL FLATS the harvesting of soft shelled clams, blood- Map Legend - F5 worms, sand worms, and other species brings Color - Green Bice tens of millions of dollars to Maine's economy Percentage of Total Coast Area Mapped and employs hundreds of people. Many kinds of - 0.08% valuable fish species, including winter flounder, depend on mud flats as feeding habitats. Other MUSSEL BAR (in part) common consumers of mud flat animals in- Map Legend - F3 clude black ducks, loons and other waterfowl, Color - Scarlet Red sandpipers and other small shorebirds, blue Percentage of Total Coast Area Mapped herons and snowy egrets. - 0.04% Planning Considerations: Mud flats are the Gravel Beach Habitats most sensitive of all Maine's interticlal habitats to disturbance caused by man. Industrial ef- Description: Gravel Beach habitats are rela- fluent, sewage and other wastes discharged or tively stable, course-grained sedimentary en- dumped on or near a mud flat may drastically vironments characterized by good percolation reduce the flat's productivity and commercial which results in a deep anoxic (oxygen-free) usefulness. Even "clean" water discharged by layer well below the sediment surface. (it shoreline industrial plants can reduce a flat's should be noted that the geologic units called productivity and diversity if the temperature of "gravel beaches" on the Marine Environments the water is significantly higher or lower then Maps are called "cobble beaches" in this hand- that of the ocean (this is called thermal book; moreover, gravel beach habitats in this loading). Oil spills can wipe out virtually all handbook include the geologic environments species living in a mud flat. And, because the referred to as "low-energy beaches" and "mix- muddy substrate this habitat is very stable and ed sand and gravel beaches" on the Marine En- scarcely flushed by water, oil can remain in the vironments Maps.) Beaches composed of sediments for many years, making the reestab- gravel in a strict geologic sense are rare in lishment of a normally diverse mud flat com- Maine. Most gravel beach habitats are gravel- munity impossible for a long period of time. sand or gravel-cobble combinations. These A potential threat to mud flats is excessive habitats occur in coves and other sheltered harvesting of clams and marine worms. Digging areas along the shoreline. Gravel, or gravel- activities disrupt the orientation, depth and sand, is often present at the inner, low-energy "homes" of young clams and other mud- portions of coves. Seaward of these inner por- dwelling species and exposes these animals to tions, gravel generally gives way to cobbles, harsh weather extremes and predators. Digging then to boulders, and then (though not always) during cold winter days is particularly disrup- to bedrock. This graduation of sediment types tive, since exposure of a cold-blooded animal to is a result of the increasing energy levels, or freezing temperatures is often quickly lethal. wave action, noted from the inner cove to the Mud flat habitats may also be disturbed or exposed point. However, while gravel beaches destroyed by dredging or filling on the flats or are considered low-energy environments, the on nearby environments. Dredging flats or dum- energy levels affecting them may still be much ping a smothering load of dredge spoil on them higher than those affecting mud or sand flats. can reduce productivity for years. Dredging of The best examples of gravel beach-to-cobble adjacent wetlands or agricultural activities and graduation are found in Penobscot Bay and, to a construction on nearby uplands can release an lesser extent, in Cobscook Bay. In other areas, unnatural influx of sediments that may smother such as Kittery, Bailey Island and Perry, the in- 31 tertidal zone of coves also commonly grades to be moved easily by heavy waves. Since cob- from gravel to cobble, but the geologic and bles are larger and heavier than gravel, they are energy structures tend to be more complex. found in locations where wave exposure, or Biological Characteristics: Gravel beaches energy levels, are somewhat higher. Frequent- are relatively harsh environments. Though not ly, cobble beaches are found next to gravel as harsh as a sand beach, where high wave ex- beaches in coves, just seaward of the gravel posure is constantly shifting the sand, gravel is habitat. Good examples of this association also moved by waves. This makes it difficult for exist in Penobscot and Cobscook Bays, and at many attached species, including algae, to Bailey Island, Perry and Kittery. As in gravel become established in any abundance, or, in beach areas, the sediments under the surface some cases, to survive at all. As a result, the of cobble beaches consists of a mixture of sand diversity of species on gravel beaches is very and gravel. During storms, heavy waves often low. In fact, species diversity is lower only on throw rocks from cobble beaches into the up- sand beaches. Nonetheless, some species are per intertidal zone, where they form low ridges. adapted to making their home in the relatively This unquestionably wreaks great havoc on the stable environment under the shifting upper animals living on the cobbles. layer of surface gravel. The most abundant FIGURE 10. Looking up a transect on a cobble species are various types of burrowing marine beach at Kennebunkport. worms. Less abundant but not uncommon are snails, barnacles, and clams. Importance: Most gravel beaches are rarely used for either recreational purposes or com- mercial harvesting of clams and marine worms and thus provide little direct economic benefits to Maine. However, the predominance of marine worms in these environments make them indirectly valuable as feeding habitats for ""A flounder and other important commercial fish species. 7" 4@' Planning Considerations: Like sand beaches, gravel beaches are often subject to gradual landward migration as a result of sea level rise, though they are less mobile than beach-dune systems. Thus, development should be set back a reasonable distance (determined by on- site evaluation). Geological Units Included: MUSSEL BAR (in part) Map Legend - F3 Color - Scarlet Red Percentage of Total Coast Area Mapped - 0.04% LOW ENERGY BEACHES Map Legend - B5 Biological Characteristics: Although cobbles Color - Magenta are moved by wave action, they do not move as Percentage of Total Coast Area Mapped readily as gravel and the surface is thus more - 4.00% stable than on gravel beaches. This allows a Cobble Beach Habitats greater number and variety of organisms to sur- vive. However, while species diversity and the Description: These habitats (called gravel abundance of individual organisms on cobble beaches on the marine environments maps) are beaches is greater than noted for gravel or sand made up of rocks large enough to be used as a beaches, numbers for both factors are still substrate for attachment by marine organisms relatively low compared to other intertidal en-' who dwell on rock surfaces, but small enough vironments. Common resident species include 32 various marine worms, isopods (small ocean gravel habitats. The boulders are also large and dwelling relatives of the mill-bugs or sow-bugs stable enough to provide a suitable substrate for found in gardens and under forest leaf litter), many attached animal species. In addition, the barnacles, periwinkle snails, and blue mussels. areas between the boulders provides shelter for Some soft-shelled clams and other bivalves a variety of organisms and the sediment beneath dwell in the sandy substrate beneath the cob- and between provides habitat for many types of bles. burrowing creatures. As a result, species diver- Importance: Like gravel beaches, cobble sity and the number of individual organisms per beaches provide little direct economic benefits square meter on boulder beaches is relatively to Maine but do provide feeding habitat for high (though not as great as noted for mud flats flounder and other valuable fish species. This and high-energy rocky shores). The most abun- indirect importance is probably somewhat dant resident species are marine worms, bar- more significant than that of gravel beaches nacles, blue mussels and periwinkle snails. since the abundance of small marine Starfish, green crabs, amphipods and isopods organisms is greater. are common here. Sea cucumbers, brittle stars, sea spiders and other interesting intertidal Planning Considerations: Cobble beaches are creatures may also be found. It is noteworthy generally unsuitable, and rarely used for, any that many of the species that reside on boulder type of development. Occasionally, roads are beaches are creatures commonly found in built behind the storm ridges. However, rocky shore habitats (a few are found only on because cobble beaches are subject to land- boulder beaches or rocky shores). ward recession due to the steady rise of world sea level, washovers resulting from wave action often necessitates constant repair of these roads. Thus, in general, roads or any other con- Importance: A direct economic benefit provid- struction should usually be set back from cob- ed by some boulder beaches is from the occa- ble beaches and their storm ridges far enough sional commercial harvesting of the dense to avoid such problems. growths of the rockweed, Ascophyllum (pro- cessed to provide food additives and micro- Geologic Units Included: nutrients for livestock and crops). However, the GRAVEL BEACHES relative abundance of small marine creatures Map Legend - B3 gives all boulder beaches indirect significance Color - Non-photo Blue as feeding areas for commercial fish species Percentage of Total Coast Area Mapped and other creatures higher on the food chain. -3.00% Many people also appreciate the aesthetic characteristics of boulder beaches, particularly Boulder Beach Habitats the beauty of the ocean-polished boulders and the sound they make when impacted by waves. Description: Boulder beaches are composed of large rocks that are generally moved only by severe storm waves. Tide pools and pockets of finer sediments are common within these Planning Considerations: Boulder beaches habitats between and beneath the boulders. are generally considered poor sites for con- Boulder beaches occur at a number of locations struction of shore facilities or other develop- along the Maine Coast. In Penobscot Bay, they ments. are often the high energy points of land on the Geologic Units Included: outer margins of coves. In other areas of the st-ate, they are found next to bedrock promon- BOULDER BEACHES tories where energy levels are slightly lower. (A Map Legend - B3 good example is at Mount Desert's Otter Point Color - Non-photo Blue area, where the bedrock cliffs give way to a Percentage of Total Coast Area Mapped boulder beach that becomes a cobble-gravel - 0.5% beach at the head of the cove.) BOULDER RAMPS Biological Characteristics: On most boulder Map Legend - Br beaches, growths of attached algae, or seaweed, Color - Non-photo Blue are present. This alone makes boulder beaches Percentage of Total Coast Area Mapped significantly different from algae-free cobble and - 2.00% 33 High-energy Rocky Shore Habitats crops, which may also be isolated from the Description: These habitats are composed of mainland as islands, provide feeding and breed- bedrock ledge located in relatively exposed ing habitat for many eider ducks, black clucks areas of the shoreline, where heavy wave action and other waterfowl, for various species of significantly affects intertidal zonation. Tide seabirds, and for harbor seals. pools are often present and are here considered Planning Considerations: Rocky shoreline a part of this habitat type. Much of Maine's coast areas that are not significant breeding areas for east of Cape Elizabeth is characterized by high- birds and seals are some of the best sites for energy rocky shores. The highest-energy areas shoreline construction and development (ex- are at headlands, such as Two Lights at Cape cluding conventional septic systems), since Elizabeth, Pemaquid Point, or Quoddy Head in they are both solid and rarely prone to erosion Lubec. problems. They also offer opportunities for harvesting of mussels and seaweeds, which are Biological Characteristics: The biological commercially important in some areas. One communities living on high-energy rocky potential threat to ledge-dwelling species is an shores consists of organisms living on rock sur- increased influx of sediments, some-times faces. At any levels on the rocky shore the caused by agricultural activities or construc- dominance of species is largely controlled by tion on nearby uplands. Such increases in sedi- the degree of exposure to waves and biological ment load may smother productive ledge interactions. These habitats usually have four habitats, a problem which can also develop distinct layers or zones. The uppermost, or high when man-made construction along the shore- intertidal zone, is the harshest. Only a few line alters current and wave patterns. Contami- species are found in this zone (primarily tiny nation by oil or toxic chemicals can also reduce forms of algae, periwinkles and small insects the productivity of ledge environments and called springtails). The other three zones host their suitability as habitat for birds and seals. an increasingly diverse variety of species. Occasionally, foot traffic, or the collecting or Moreover, the numbers of individual organisms havesting of mussels, seaweed and other per square meter is execptionally high, far more species may become excessive on a popular than any other type of intertidal habitat. Below stretch of rocky shore. In such cases, some the high intertidal zone on the rocky shore lies limitating of these activities may be necessary the barnacle zone, dominated by dense popula- to prevent localized reductions in species diver- tions of barnacles and blue mussels. Also com- sity or to preserve aesthetic qualities or special mon in this zone are small amphipods and natural areas. marine worms. Below is the rockweed zone, Geologic Units Included: noted by dense growths of rockweed, large LEDGE (in part) marine algae and an abundance of periwinkles. Map Legend - M Other common residents of the rockweed zone Color -- Warm Light Grey include dog whelks, limpets, blue mussels, Percentage of Total Coast Area Mapped horse mussels and rock barnacles. The lowest - 12.00% layer of high-energy rocky shores is called the Chondrus zone, named for the dense growths Low-energy Rocky Shore Habitats of Irish Moss (Chondrus crispus) found here. Description: These are habitats composed of Among the most common animal residents of bedrock located in interticlal areas protectbd this zone are green sponges, limpets, from heavy wave action. (Though low-energy periwinkles, baltic clams, amphipods, green rocky shores are ecologically different from crabs and starfish. Other species commonly high-energy rocky shores, both are referred to found here include various anemones and nudibranchs (shell-less relatives of the snail), collectively as "ledges" on the marine environ- rock crabs, blood starfish, brittle stars and sea ments maps.) Low-energy rocky shores are urchins. often found in coves whose width is narrow enough so that waves cannot build up to any ex- Importance: Direct economic benefits result tent and the shore is not exposed to the energy from the harvesting of rockweed and Irish of the open ocean. These are common habitats moss, blue mussels and periwinkles from some found in many areas along Maine's irregular high-energy rocky shores. Also significant are coastline. Most low-energy rocky shores the aesthetic and educational values of these studies have a layer of silt coating the surface. interesting and productive habitats. Ledge out- of the rocks and attached seaweeds. 34 FIGURE 11. The low-energy rocky shore in East range from fringe marsh at the heads of mud Waldoboro. flats and estuaries to the broad expanses of h often found behind dune-beach systems. P6 mars For example, the Scarborough Marsh behind Pine Point at the northern end of Old Orchard Beach includes about 20 percent of Maine's total salt marsh area. Biological Characteristics: Salt marshes are ecologically rich environments, with relatively high numbers of individual organisms per square meter. The diversity of resident species is only moderate, but many "transient" species V@ of fish, birds and mammals use marshes as feeding, nesting or nursery habitats. In the mud beneath the dense growths of marsh grasses, burrowing marine worms are particularly abun- Biological Characteristics: Biologically, low- dant. Other common resident species include energy rocky shores are moderately productive. amphipods, snails, ribbed mussels and soft- The variety of species falls between that of shelled clams. Crabs and juvenile fishes of gravel and cobble beaches. The abundance of various species frequently live in the tidal individual organisms is less than on mud flats, streams running through salt marshes. boulder beaches and high-energy rocky shores. Importance: Salt marshes, once viewed as Dominant species include rockweeds, bar- useless, mosquito-breeding wastelands, are nacles, segmented marine worms, periwinkles now generally considered one of our most and blue mussels. Other common residents in- valuable intertidal habitats. The rich organic clude green crabs, isopods and limpets. detritus flushed from marshes by the tides pro- Importance: Similar to that described for vide crucial nutrients upon which many oceanic high-energy rocky shores. food chains are based. Many species important Planning Considerations: Similar to those to Maine's commercial fisheries live, feed, or listed for high-energy rocky shores. spend their early life stages in salt marsh habitats. Ospreys, bald eagles, various shore- Geological Units Included: birds and waterfowl and numerous colorful LEDGE (in part) songbirds feed or nest in marsh areas. Beyond Map Legend - M their significant function as wildlife habitats, Color - Dark Brown marshes temporarily store flood waters, thus Percentage of Total Coast Area Mapped reducing the severity of coastal flooding. Wide - 12.00% bands of marsh land in front of upland shores absorb the brunt of heavy storm waves, thus VENEERED RAMP protecting the mainland from severe erosion Map Legend - F6 and property damage. In addition, the dense Color - Dark Brown marsh vegetation often captures and holds Percentage of Total Coast Area Mapped pollutants and sediments that could otherwise - 0.05% run off into shellfish beds and navigational channels. Salt Marsh Habitats Description: Salt marshes are dominated by Planning Considerations: Salt marshes are thick stands of marsh grasses, characteristically very sensitive to changes in the volume of cord grass (Spartina alterniflora) and salt marsh water flowing into and out of them. Dredging, hay (Spartina patens). The nutrient-rich sub- ditching or filling activities on or near marshes strate in these environments is composed of can change the hydrology of these habitats and mud, grass roots and peat (the decomposed re- thus their ecological productivity. Dredging can mains of marsh plants). Maine has a relatively also release chemicals or heavy metals former- limited amount of salt marsh along its coast, ly bound up in the marsh sediments which may comprising only about 5 percent of the total be toxic to fish and shellfish. Pollution by shoreline zone. Most of these marsh lands are pesticides or oil can have similarly adverse ef- found on the southern and central coast. They fects on marsh organisms. Light or heavy 35 development, roadbuilding and most other LOW SALT MARSH types of construction are not considered suit- Map Legend - M2 able on marshes, nor is the disposal of solid or Color -- Peacock Green liquid wastes. On the whole, the most ap- Percentage of Total Coast Area Mapped propriate activities in these environments are -0.10% recreational, such as hunting, birdwatching, MARSH LEVEES boating, and canoeing. Occasionally, in areas Map Legend - M3 of heavy use, foot traffic can cause devegeta- Color -- Peacock Green tion that may lead to minor erosion problems. Percentage of Total Coast Area Mapped Excessive boat traffic may also lead to bank - 0.01% erosion and increased water turbidity along SALT PANNES AND PONDS tidal streams. Map Legend - M4 Geologic Units Included: Color -- True Blue HIGH SALT MARSHES Percentage of Total Coast Area Mapped Map Legend - M1 - 0.05% Color - Peacock Green Percentage of Total Coast Area Mapped - 5.00% 36 FIGURE 12. The high-energy rocky shore at Cape Neddick. so@ 7 38 CHAPTER 4 A SAMPLER OF INTERTIDAL SPECIES The intertidal zone of Maine is rich in the Mya arenaria, commonly known as the soft- number of variety of species which inhabit it. shelled clam, is an important commercial and Many of the species occur in several habitats recreational species in New England and the over a wide geographic range. Others are quite Chesapeake Bay. In Maine, this bivalve is specific to a given habitat or location. The generally harvested from mudflats, but it is also following section provides brief natural history abundant on other substrates such as sand or sketches of some species common to our gravel. It may live subtidally in estuaries and region. can live throughout most of the intertidal zone; FIGURE 13. Drawing of Mya arenaria (left) and however, it reaches its greatest size in the Macorna balthica showing their relative positions lower intertidal zone, where its feeding period in the sediment. Arrows illustrate the movement as a filter feeder is maximized. Its food consists of water and sediment through Macorna. primarily of phytoplankton (free-floating unicell- ular algae). The spawning season varies along the Maine coast, but lasts generally from May to September. After a two-week planktonic larval stage (which plays an important role in disper- sal of the species), the organism settles to the bottom and establishes a permanent burrow. Populations of the soft-shelled clam may reach a density of over 300 per square meter. It's most serious competitor is the blue mussel, Mytilus edulis, which can overgrow clam beds. Predators include flounder, ducks, horseshoe crabs, green crabs, and moon snails. 39 FIGURE 14. The shell of the baltic clam, Nucella lapillus, the dog whelk, is a gastropod,. Macoma balthica, a dominant resident of Maine's or snail, commonly found on rocky substrates. intertidal zone. in the intertidal zone from Cape Cod to the Bay of Fundy. It is generally white with orange or brown bands, and may reach a length of 30 mm. Spawning may occur at any time of the year, and there is no planktonic larval stage. The lar- vae hatch looking like miniature adults and move to the lower intertidal zone where they feed on tiny polychaete worms and young mussels. As adults, they inhabit a higher area of the intertidal zone and feed primarily on bar- nacles and adult mussels by boring directly through the shells of their prey. This species The baltic clam, Macoma balthica, is a domi- often occurs in dense clusters, especially nant intertidal species occurring most com- under rockvveeds. Nucella is vulnerable to ice monly in mud. In the western Atlantic, its range and extreme cold, but it may withstand extended extends from the Arctic Seas to Georgia, and it exposure to the atomsphere, although not as' occurs throughout the world at similar latitudes. long as barnacle Balanus balanoides. Its chief Macoma is a deposit feeder, feeding on detritus predators are gulls and sandpipers. and bacteria, using its vacuum-like siphon to take sediment from the water-mud interfaGe. Its feces may be recolonized by bacteria and again become a food source for Macoma and other deposit feeders. FIGURE 16. The common and widely distributed After a 2-5 week planktonic larval stage, the periwinkle, Liftorina fifforea. Baltic clam settles to the bottom and changes into an adult. Its primary competitor is the am- phipod, Corophium voluntator, which not only competes for food, but may often prevent suc- cessful settlement of the planktonic larvae, thereby disrupting the development cycle of the clam. Macoma is probably eaten by a number of predators. The polychaete worm, Nephtys, preys heavily on the larval clams and the adults are eaten by fish and birds. FIGURE 15. The dog whelk, Nucella lapillus, a common predator of barnacles and mussels on This gastropod species is the common peri- rocky shores. winkle, found in great abundance throughout the intertidal zone on both sides of the Atlantic. On the western side, it occurs from Labrador to Maryland. In Maine, it occurs on both rocky shores and mud flats, where it grazes on sur- face films of algae, algal detritus, diatoms, and lichens. Spawning takes place in February and March, and the larvae are planktonic until May or June, when they settle and undergo metamorphoses. Littorina exhibits a daily pattern of migration, towards land at dusk and sea at dawn. This may. be an adaption for withstanding long periods of exposure. Gulls and flounders are its chief predators. Competitors for food and space are numerous and include other molluscs, asci- dians, barnacles, hydroids, and sponges. 40 FIGURE 17. Corophiurn volutator, the dominant boat bottoms, and feeds on phytoplankton, amphipod of mud flats in Maine and Europe. selectively filtering certain types from the water. It is resistant to desiccation and is capable of breathing in air; both qualities make it highly adapted to life in the upper intertidal zone. All barnacles have both male and female sex- ual organs. They cross-fertilize in the fall and release tiny, shell-less planktonic larvae in late winter or early spring. These larvae comprise a major portion on the plankton during this time of year. Settlement occurs in early summer and is influenced by several factors, including the Corophium volutator is a tube-dwelling am- nature of the substrate and surrounding fauna. phipod crustacean found intertidally, especially Predators of the barnacle vary with the stage in estuaries and salt marshes, on both sides of of the life cycle: herring feed on planktonic lar- the Atlantic. Its range extends from Norway to vae, periwinkle on newly settled individuals, the Adriatic and the Bay of Fundy to New and dog whelks, crabs, and polychaetes on Hampshire. It is a dominant species in areas adults. There is spatial competition within the with fine-grained sediment, particularly mud. species and with other species such as blue Population densitites may be as high as 60,000 mussels, rockweed, colonial tunicates and en- per square meter. Corophium is capable of both crusting bryozoa. In Maine, densities of bar- deposit feeding (in or out of the burrow) and nacles have been observed up to 160,000 per filter feeding, using its feathery respiratory square meter. system. FIGURE 19. The commercially important sand Breeding season ranges from early to late worm, Nereis virens. spring. Fertilization is external and develop- ment is direct, i.e. there is no free floating larval stage. The young are brooded by the mother un- til they resemble small adults, and are then released. Significant predators are shorebirds and flounders. The major competitor is the polychaete worm Nereis diversicolor. Frequent- ly Corophium is so abundant that it prevents the successful settlement of the larvae of other species, such as the Baltic clam. FIGURE 18. The rock barnacle, Balanus balanoides, which reaches densities of up to 160 'OOO/M2 on rocky shores. Known as the clam-worm or sandworm, Nereis virens is a very common polychaete worm in intertidal mud flats, mussel beds, and occasionally subtidally. It may reach a length of about three feet (1m). This species often leaves its burrow at night to swim and feed. As in the case of many polychaetes, feeding methods of Nereis may be variable, depending on food The rock barnacle, Balanus balanoides, is source, and differ between populations. It has found abundantly in the upper intertidal zone been shown to feed on small animals, plants from the Arctic to Delaware and on the eastern and plankton. side of the Atlantic. Though covered with Spawning usually occurs in May, during a several hard calcareous plates resembling a new moon, as the worms swarm at the water shell, the barnacle is actually a crustacean like surface, releasing their eggs. crabs and amphipods. It attaches permanently Nereis virens is an important food source for to hard substrates, such as rocks, pilings, and fish and crabs, and is also a commercially im- 41 portant species in Maine, utilized as bait for Oligochaetes are a class of annelid, sport fishing. This species can withstand a segmented worms. Various species may be broad range of salinity and has a wide geo- found from the intertidal zone to the deep graphic distribution: Norway to France, Iceland, ocean in sediment, decaying vegetation, and and Newfoundland to Virginia. under rocks. They are predominantly burrow- dwellers that feed non-selectively on bottom FIGURE 20. The cone worm, Pectinaria gouldii, deposits. Chief competitors are other deposit- showing both the worm-itself and its natural feeders, including polychaetes, molluscs, posture in the sediment. crustaceans, and echinoderms. Oligochaetes are undoubtedly preyed upon by several species: chief among them is the winter flounder. Oligochaetes have both male and female sex- ual organs and usually undergo cross-fertiliza- tion. There is no larval form. In some cases, asexual reproduction by fission may occur. Re' cent evidence suggests that certain oligochaeto species may be important in- dicators of pollution. Certain populations may become dominant in areas where there is an in- Pectinaria gouldii, the cone worm, is a tube- crease in concentrations of organic matter and dwelling polychaete which is often found in decrease in oxygen concentration (for example, soft intertidal and subtidal sediments, especial- in the area of sewage outfall). ly sand and mud. Its tube is shaped like an ice FIGURE 22. The acorn worm, Saccoglossus cream cone which is open at both ends, and it kowalevski, in a typical burrow showing & is made of secretion. The worm lives head down characteristic fecal mass. in the sediment and is a deposit feeder, stripping the diatoms and detritus from the sediments it ingests. Knowledge of its reproductive cycle is in- complete. Sexes are separate, fertilization is ex- ternal, and there is a planktonic larval stage. It is preyed primarily upon by fish. FIGURE 21. An example of one of the species of oligochaetes which are abundant all along the Maine coast. Saccoglossus kowalevski, an acorn worm, lives in intertidal and subtidal sand and mud, ranging at least from Maine to North Carolina. It constructs a mucous-lined burrow, open at both ends, from which it extrudes its castings into large piles. It feeds unselectively on the surrounding deposits with its long proboscis. Sexes are separate and fertilization is external. There is no planktonic larval stage. Predators of Saccoglossus are not well known, but other species of this group are known to be preyed upon to some extent by crabs and fish. 4-2 FIGURE 23. Title 38, �471-478, Alterations of Coastal Wetlands* � 471. Prohibitions pleted application for a permit, the municipality shall either issue the permit or deny the permit setting forth the reasons therefor No person shall dredge or cause to be dredged, drain or cause or order a hearing thereon within 30 days of the order for which to be drained, fill or cause to be filled or erect or cause to be hearing adequate public notice shall be given. Within 30 days erected a causeway, bridge, marina, wharf, dock Or other per- after the adjournment of the hearing, the municipality shall either manent structure in,on, or over any coastal wetland; or bulldoze, issue the permit or deny the permit setting forth the reasons remove, add or displace sand, or build any permanent structure therefor. In the event that a permit applied for is denied by the in, on or over any coastal sand dune without first obtaining a municipality, the applicant may request a hearing before the permit therefor from the Board of Environmental Protection municipality with reasonable public notice given. or a municipality acting under the provisions of section 473 and 474; nor shall any action be taken in violation of the conditions The board shall issue no permit without notifying the municipal- of such permit, once obtained. ity in which the proposed alteration is to occur and considering any comments filed within a reasonable period by that � 472. Definition municipality. As used in the alteration of coastal wetlands law, unless the No permit issued by a municipality may become effective until context otherwise indicates, the following terms shall have the 30 days subsequent to its issuance, but if approved by the board following meanings. in less than 30 days then the effective date shall be the date of 1. Coastal sand dunes. "Coastal sand dunes" are sand approval. A copy of the application for the permit and the per- deposits within a marine beach system above high tide including, mit issued by the municipality shall be sent to the board im- but not limited to, beach berms, frontal dune ridges, back dune mcdiately upon its issuance by registered mail. The board shall areas and other sand areas deposited by wave Or wind action. review that permit and either approve, deny or modify it as it Coastal sand dunes may extend into the coastal wetlands. deems necessary. Failure of the board to act within 30 days of the receipt of the permit by the municipality shall constitute its 2. Coastal wetlands. "Coastal wetlands" are all tidal and sub- approval and the permit shall be effective as issued. tidal lands including all areas below any identifiable debris line When winter Conditions prevent the board or municipality from left by tidal action, all areas with vegetation present that is evaluating a permit application, the board or municipality, upon tolerant of salt water and occurs primarily in a salt water habitat, notifying the applicant of that fact, may defer action on the ap- and any swamp, marsh, bog, beach, flat or other contiguous plication for a reasonable period. The applicant shall not dur- lowland which is subject to tidal action or normal storm flowage ing the period of deferral fill or cause to be filled, dredge or cause at any time excepting periods of maximum storm activity. Coastal to be dredged, drain or cause to be drained or otherwise alter wetlands may include portions of coastal sand dunes. that coastal wetland. � 473. Permit granting authority 2. Sand dunes permit. If the applicant for a sand dunes per- All permits shall be issued by the Board of Environmental Pro- mit demonstrates to the satisfaction of the board or municipali- tection, except that a municipality may apply, on forms provided ty, as appropriate, that the proposed activity will not by the board, to the Board of Environmental Protection for unreasonably interfere with existing recreational or wildlife uses; authority to issue such permits. The board shall grant such unreasonably interfere with the natural supply or movement of authority if it finds that the municipality has: sand within or to the sand dune system; unreasonably increase the erosion hazard to the sand dune system; or cause an 1. Planning Board. Established a planning board; unreasonable flood hazard to structures built in, on or over any coastal sand dune or neighboring property, the board or 2. Adopted zoning ordinance. Adopted a zoning ordinance municipality shall grant the permit upon such terms as are approved by the board and the Land Use Regulation Commis- necessary to insure that the proposed activity will comply with sion, pursuant to Title 12, chapter 424; the foregoing standards. 3. Notice. Made provision by ordinance or regulation for 3. Single permit. In the event that a project affects both prompt notice to the board and the public upon receipt of ap- wetland areas and sand dune areas, the board or municipality, plication and written notification to the applicant and the board as appropriate, shall grant a single permit upon such terms as of the issuance of or denial of a permit stating the reasons are necessary to comply with the foregoing standards. therefor; and 4. Application form. The application form shall be the same � 475. Penalties as that provided by the Board of Environmental Protection. A violation is defined as any filing, dredging, draining, in the event that the board finds that a municipality has failed depositing, altering, erecting or removal of materials which takes to satisfy one or more of the above lis;ed criteria, it shall notify place in coastal wetlands or coastal sand dunes contrary to the the municipality accordingly and make recommendations through provisions of a valid permit or without a permit having been which it may establish compliance. The municipality may then issued, and without regard to whether these physical acts were submit a modified application for approval. witnessed as they were being carried out or whether the action was willfully undertaken to avoid the intent of this subchapter If at any time the board determines that a municipality may or without knowledge of this subehapter undertaken. Any such be failing to exercise its permit granting authority in accordance filling, dredging, draining, depositing, altering or removal of with its approval procedures or the purposes of this Article as materials shall be prima facie evidence that it was done or caus- embodied in the standards set forth in section 474, it shall notify ed to be done by the owner of the coastal wetlands or coastal the municipality ofthe specific alleged deficiencies and shall order sand dunes. a public hearing, of which adequate public notice shall be given, to be held in the municipality to solicit public or official com- � 476. Enforcement ment thereon. Following such hearing, if it finds such deficien- Inland fish and game wardens, coastal wardens and other law cies, it may revoke the municipality's permit granting author- enforcement officers enumerated in Title 12, section 7055 shall ity. The municipality may reapply for authority at any time. enforce this sulichapter. � 474. Permits; standards � 478. Exemptions 1. Wetlands permit. If the applicant for the wetlands permit The Board of Environmental Protection may by rule or regula- demonstrates to the satisfaction of the board or municipality tion exempt from this sulichapter certain activities including, but as appropriate, that the proposed activity will not unreasonably not limited to, repairs and maintenance of existing structures interfere with existing recreational and navigational uses; nor or waive such procedural requirements as it deems not inconsis- cause unreasonable soil erosion; nor unreasonably interfere with tent with the purposes of this subchaptcr. Nothing in this sub- the natural flow of any waters; nor unreasonably harm wildlife chapter shall prohibit the minor repair of existing permanent or freshwater, estuarine or marine fisheries; nor lower the quality of any waters, the board of muncipality shall grant the permit structures which would require less than a total of one cubic yard upon such terms as are necessary to insure that the proposed of material to be filled, deposited, dredged, moved or removed activity will comply with the foregoing standards. in any coastal wetland or normal maintenance or repair of presently existing ways, roads or railroad beds nor maintenance In municipalities that have been delegated the authority to issue and repair of installations and facilities of any utility as defined permits under this Article, within 30 days after receipt of a com- in Title 23, section 255, abutting or crossing said coastal wetlands, provided no watercourse is substantially altered. *Administered by: Maine Department of Environmental Protection, Bureau of Land Quality Control, State House Station #17, Augusta, Maine 04333. 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