[Congressional Record (Bound Edition), Volume 146 (2000), Part 18]
[Senate]
[Pages 25928-25930]
[From the U.S. Government Publishing Office, www.gpo.gov]



                         ADDITIONAL STATEMENTS

                                 ______
                                 

                            STELLAR SEA LION

 Mr. STEVENS. Mr. President, after my remarks yesterday on the 
Steller sea lion decline, members of the press corps asked me for 
proof. This article provides a good summary of the research behind the 
sea lions' decline. I would also point out that the burden should be on 
the plaintiffs and the agency to prove that fishing has caused the sea 
lions' decline.
  I ask that an article from the Pacific Fishing magazine be printed in 
the Record.
  The article follows.

                   [From Pacific Fishing, Nov. 2000]

                            The Wrong Cure?

  Now that an unproven hypothesis has beached the North Pacific trawl 
 fleet, environmental litigators have what they want. Are they honest 
     enough to support research on whether their ``reasonable and 
            precautionary'' solution really helps sea lions?

                     (By Jeb Wyman and Brad Warren)

       When Judge Thomas S. Zilly banned trawling in 50,000 square 
     miles of water designated as critical habitat for Steller sea 
     lions, he issued a legal finding that groundfish fisheries 
     off Alaska posed ``a reasonably certain threat of imminent 
     harm'' to the endangered animals.
       That phrase means plenty in court, but it doesn't carry 
     much weight in the world of science, where evidence of the 
     supposed threat from fishing has been repeatedly 
     characterized as ``tenuous.'' Significantly, even the judges 
     stopped short of endorsing any particular theory about what's 
     shrinking the sea lion population. Instead, he focused on a 
     legal principle established by prior courts' interpretations 
     of the Endangered Species Act: If government and industry 
     can't demolish the contention that fishing threatens the 
     Stellers, then they must assume it does and restrain 
     fisheries accordingly. (See ``Who Killed the Stellers?'' 
     Pacific Fishing, October 2000, page 20.)
       This converts a merely plausible threat to the Stellers 
     into a legal mandate. Thus the three environmental groups 
     that filed the

[[Page 25929]]

     lawsuit never had to prove that fishing is killing off sea 
     lions. Nor did they need to show even that fishing is a more 
     likely suspect than the other culprits that scientists are 
     investigating. Those culprits include thoroughly documented 
     changes in ocean climate and shifts in the available prey 
     base for Stellers; they also include killer whales that have 
     been videotaped devouring sea lions--a diet that one study 
     calculates to account for most of the Stellers' recent rate 
     of decline.


                              a weak heart

       In fact, the environmentalists' case is weakest at its 
     heart. It depends upon the theory of ``localized depletion.'' 
     This theory contends that trawl nets temporarily scoop out 
     holes in schools of fish, or disperse them, for long enough 
     so that Steller sea lions can't find enough food and thus are 
     going extinct. No matter how it plays in court, in the harsh 
     light of scientific inquiry the evidence and the logic behind 
     this theory still are viewed as shaky, and other theories 
     carry greater credence. For starters, the only field research 
     to find evidence for localized depletion focused entirely on 
     the Atka mackerel fishery, and even there the study's 
     methodology and conclusions have been challenged by other 
     scientists. Some scientists point to the complete absence, so 
     far, of published field studies on whether pollock or cod 
     fishing causes localized depletion. ``That's all basically a 
     hypothesis,'' says Dr. Dayton Lee Alverson, a senior 
     scientist who served on a federal panel investigating the 
     Steller sea lion decline.
       Scientists have many misgivings about the localized 
     depletion hypothesis. For one, it appears that Stellers eat 
     different fish than trawlers catch. Alverson points out that 
     the Stellers' known foraging depths are much shallower than 
     the waters where most pollock trawling occurs. Scientists 
     also agree that the Stellers forage on smaller fish than 
     trawlers target.
       Another point of dispute is just how long any supposed 
     ``hole'' or ``dispersal'' in schools may last. The assertion 
     that ``depletion'' persists for long enough to strave sea 
     lions relies on assumptions that few scientists or fishermen 
     with any sea time can credit: that nearby fish don't swim 
     into the gap left behind a trawl, and that fish don't 
     migrate. (It's hard to show depletion after a fishing season 
     when you know the fish would normally move on anyway.) If 
     schools didn't ``in-fill,'' why would trawlers keep towing 
     the same patch of water over and over? If migration didn't 
     occur, why would fish seasonally pass through various fishing 
     locations?


                     ``conjectures,'' not ``facts''

       The National Marine Fisheries Service has drawn sharp 
     criticism in the scientific community for allowing the 
     tenuous hypothesis of localized depletion to drive fishery 
     management. The North Pacific Fishery Management Council's 
     Scientific and Statistical Committee, which includes 
     scientists from universities and fisheries agencies around 
     the country, has roundly condemned NMFS's new draft 
     environmental assessment of cod fishery impacts on Stellers, 
     which basically extends the depletion assumption to cod 
     fisheries. The document relies on a ``flawed'' analysis to 
     support that assumption, and it ``fails to clearly 
     differentiate between conjectures and facts,'' the committee 
     wrote in September. Calling for research to ``find out what 
     works and what doesn't'' in protecting Stellers, the 
     committee wrote: ``No one would object to the adoption of 
     reasonable measures to arrest the decline if there was some 
     assurance that they would lead to some improvement.'' But the 
     scientists observed that the present lack of convincing 
     evidence to balame fishing puts the council in a bind: ``If 
     there is a connection between current fisheries and Steller 
     sea lions and no action is taken, the council would be 
     derelict in its responsibility to conserve resources under 
     its domain. If other factors are responsible and the council 
     imposes stringent measures, then the council would deprive 
     individuals and even communities of their livelihoods with no 
     justification.''
       But the theory of localized depletion is crucial to the 
     trawlers' foes, because it is clear that the U.S. fishery has 
     not caused large-scale depletion of pollock stocks off 
     Alaska. Between 1980 and 1990, when Steller numbers dwindled 
     most rapidly, total pollock biomass in the Bearing Sea 
     averaged 13.3 million metric tons, nearly twice the average 
     of the previous decade. Catches averaged 1.1 million mt, 
     representing a harvest rate between 5% and 15% of the total 
     biomass. With 12 million tons of pollock remaining in the 
     water, on average, how likely was it that the 40,000 or so 
     Stellers in the endangered western population couldn't find 
     enough pollock to eat? Between 1970 and 1980, when Alaska's 
     western and eastern Stellers combined numbered between 
     200,000 and 250,000 animals, average pollock biomass was just 
     6.9 million tons.
       So for most of the years of Steller decline, more pollock 
     has been available for them to eat than during the previous 
     20 years, when the sea lion population was an order of 
     magnitude larger. As biologists say, it's a ``negative 
     correlation.''
       What's more, attempts to link population crashes at Steller 
     rookeries with commercial fishing have come up short. A 1989 
     paper by NMFS biologists Richard Merrick and Tom Laughlin 
     found only a handful of correlations, which turned out to be 
     both positive and negative. A 1996 study by David Sampson 
     showed a big decline in Steller numbers at rookeries near 
     heavy pollock winter fishing and in places where no winter 
     catches had occurred at all. In other words, the animals did 
     badly whether anyone fished near them or not.
       Still, the theory of localized depletion remains the focus 
     of the Steller debate. The only attempts to measure localized 
     depletion have tried to show declining Catch Per Unit of 
     Effort (CPUE) over time. If localized depletion is occurring, 
     the density of fish schools will decrease as vessels soak up 
     the fish. As total catch accumulates, every hour of trawling 
     should produce fewer and fewer fish. Studies chasing this 
     reasoning, however, rely on a key assumption that many 
     scientists say just doesn't make sense: These studies assume 
     that the schools are closed systems, with no fish entering or 
     leaving the ``box,'' either by migration or mortality. They 
     assume that only fishing removes fish.


                          repeat that, please?

       Repeated efforts to prove localized depletion by 
     demonstrating a decline in CPUE have had mixed results. Only 
     one field study supports the notion of localized depletion: 
     NMFS biologist Lowell Fritz's research on the Atka mackerel 
     fishery in 1998 found a ``statistically significant'' CPUE 
     decrease in 16 of 26 areas. Martin Smith, a graduate student 
     at the University of California at Davis, reworked data in a 
     March 1999 report and concluded that depletion had occurred 
     in five of six locations. But similar studies on the pollock 
     and cod fisheries have produced less conclusive results. 
     Plots of daily cod catch in 1998, measured as catch per hour 
     of towing, produce an untidy geography of dots, with peaks 
     and valleys and plateaus. Localized depletion, as shown by 
     declining CPUE, isn't at all clear. It takes a statistician's 
     determined hand to massage the data into a gently sloping 
     line.
       What does that gently sloping line indicate? If fish don't 
     move, a gently sloping line is what you'd expect: after all, 
     fish are being pulled into boats. But as many fisherman and 
     scientists point out, it's unreasonable to assume that fish 
     don't move. Fishermen follow fish to stay on top of them; 
     witness this year's pollock A season, when trawlers roved 
     into, through, and out of the Bering Sea's Catcher Vessel 
     Operational Area, shadowing the pollock. Allen Shimada and 
     Daniel Kimura, who tagged 12,396 cod between 1982 and 1990 
     and charted their movements around the Bering Sea, amply 
     documented the fact that cod migrate.
       A central problem in studies of localized depletion is the 
     quality of the data. None of the localized depletion studies 
     have used data that adequately account for variations in boat 
     and net size. More horsepower means a bigger net; a bigger 
     net means more fish per hour of towing. The slightly lower 
     CPUE toward the end of the 1998 cod season, for example, 
     might only reflect the departure of big boats with big nets 
     from the fishery. It could also reflect cod incidentally 
     caught by boats in other fisheries, or normal seasonal 
     movements that make cod harder to catch.
       Terry Quinn, a statistician and population dynamics 
     professor with the University of Alaska-Fairbanks and also a 
     member of the North Pacific Fishery Management Council's 
     Scientific and Statistical Committee, has begun a two-year 
     stud of localized depletion data. ``There's a great deal of 
     frustration among us scientists,'' he says. ``As the resource 
     manager, the council has the responsibility to manage the 
     fish population for fishermen, as well as the whole health of 
     the ecosystem. But the evidence for a strong relationship 
     between the fishery and the Steller sea lion is tenuous at 
     best. It focuses attention away from other theories, such as 
     ecosystem change, that also deserve attention. If you focus 
     only on a single issue you might blow it.''
       In this case, the single issue that environmentalists have 
     litigated into the status of orthodoxy rests on a slender 
     pedestal of scientific evidence. No scientific publication 
     has accepted a paper analyzing localized depletion.


                           Who Swiped Lunch?

       In contrast, the scientific literature teems with papers 
     describing the profound climatic regime shifts of the North 
     Pacific. Following the regime shift in 1976-77, after roughly 
     a 20-year ``cool'' period, the stocks of dozens of fish 
     species experienced drastic changes. Small-mesh surveys of 
     the Gulf of Alaska conducted by NMFS since 1953 have accrued 
     more than 90,000 individual catch records. They record the 
     precipitous decline of shrimp, capelin, Tanner crab, red king 
     crab, herring, greenling, and Atka mackerel during the 
     current ``warm'' period. While these stocks withered, others 
     surged: pollock, sole, arrowtooth flounder, jellyfish, 
     halibut, and others.
       As fish stocks rearranged themselves, so did higher 
     predators. The Stellers took a nose dive: an annual 24% 
     decline between 1980 and 1990 followed that regime shift in 
     the late 1970s. As the rich, oily prey species declined, so 
     did the marine mammals that eat them. The Steller's pinniped 
     cousins, harbor seals, lost 80-90% of their population in 
     that same decade; Northern fur seals are at about 50% of 
     their historic population.

[[Page 25930]]

     Populations of kittiwake and murres, coastal seabirds that 
     forage on the same fish as Stellers, also plunged.
       So, was it Mother Nature that swiped the sea lions' 
     nutritious lunch, giving them nothing but a horde of 
     groundfish full of empty calories to eat? The ``junk food'' 
     theory says so. This theory suggests that Stellers now eat 
     too much low-fat pollock and cod because of their 
     superabundance, and eat too few fat-rich species like 
     herring, sandlance, capelin, and smelt because there aren't 
     enough around. The premise relies on 50 years of studies on 
     the diet of Stellers, based on stomach contents and scat 
     analyses. But scat analyses are imperfect because the bones 
     of forage species such as capelin don't usually endure the 
     digestive process. In other words, if Stellers eat a lot of 
     them, the scat might not show it.
       It's also uncertain whether Steller sea lions eat 
     opportunistically or selectively, whether they eat a 
     different meal every dive, whether they eat different foods 
     during different seasons. Nonetheless, a number of respected 
     researchers are convinced that the Steller diet includes a 
     far greater percentage of pollock since the regime shift. 
     Among them is Andrew Trites, the head of the Marine Mammal 
     Research Unit at the University of British Columbia and the 
     director of a multi-university research consortium in the 
     U.S. and Canada that has been trying to sort out what's 
     happening to the Stellers and the ocean ecosystems where they 
     live. Trites says the data show that Stellers in the Gulf of 
     Alaska have steadily increased their diet of pollock, from 
     32% in 1976-78 to 85% by 1990-93. After the same time, 
     consumption of fatty fishes decreased from 61% to 18%.
       Besides the evidence of sea lion diet changes, nutritional 
     stress has for years been a favorite explanation for the 
     Stellers' decline because of other observations. Stellers are 
     smaller than they once were, and reproductive success has 
     dropped by about a third--classic signs of an ecosystem with 
     reduced carrying capacity.
       Still, not everyone believes in the junk-food theory. ``The 
     junk-food theory is junk,'' says Vidar Wespestad, a biologist 
     formerly at NMFS and now a consultant for the whiting 
     fishery. ``The genus name for pollock is Theragra, which 
     means `animal food.' When the species was named at the start 
     of the 19th century, I'm sure it was based on the fact that 
     it was noted as a major food item of sea lions. The whole 
     food thing is tenuous. There has never been shown to be a 
     food problem with Steller sea lions in the wild. You don't 
     find emaciated Stellers washing up on the beaches.''
       Whether or not Stellers always ate pollock, Trites's 
     empirical work is widely considered a solid showing that 
     Stellers cannot live on pollock alone. In a paper published 
     this year in the Canadian Journal of Zoology, Trites and his 
     colleague David Rosen present results of dietary experiments 
     with six juvenile Stellers. The sea lions received 
     alternating diets of herring and pollock, as much as they 
     wanted to eat, for periods of 11 to 24 days. The animals 
     individually lost between 1.4% and 16.4% of their body 
     weight, an average of more than half a kilogram a day, on the 
     all-pollock diet. Trites and Rosen attribute the results to 
     the measured lower nutritional value of pollock than herring, 
     and the higher energy cost to digest it. Clearly it is ``much 
     more difficult for Steller sea lions to thrive on a diet 
     consisting primarily of pollock,'' he writes. ``Steller sea 
     lions would have to consume an average of 56% more pollock 
     than herring to maintain a comparable net energy intake.''
       It happens that, in the Bering Sea, nature lately has set 
     the Steller's table with a diet mainly of pollock. Other 
     scientists have also found evidence that this may be 
     unhealthy for Stellers. A study by NMFS biologist Richard 
     Merrick in 1997, for instance, determined that Steller 
     populations with the least diet diversity--those eating the 
     highest percentage of pollock--suffered the greatest decline.
       If, in fact, too much pollock is harming the Stellers, 
     there's a peculiar irony afloat: fishing may actually help 
     the Steller population. Adult pollock (three year and older) 
     are cannibals, voraciously feeding on smaller juvenile 
     pollock, which are the preferred prey of Stellers. Trawlers 
     target adult pollock, reducing their consumption of 
     juveniles. Year-by-year graphing of adult pollock biomass 
     compared to juvenile biomass neatly shows the inverse 
     relationship of adult to juvenile pollock.
       Even so, don't expect Stellers to rebound just by 
     increasing fishing effort. According to John Piatt, a 
     researcher at the U.S. Geological Survey's Alaska Biological 
     Research Center, large predatory groundfish currently eat 10 
     to 100 times more forage fish than seabirds, marine mammals, 
     and humans combined. It may be, as Andrew Trites says, that 
     ``the solution to restoring the numbers of Steller sea lions 
     is probably out of human control.''
       But whether it's hunger or some other cause of death, the 
     reaper has been selective. Population studies by Anne York of 
     NMFS's Alaska Fisheries Science Center found that adult 
     survival was essentially stable; juveniles, however, declined 
     10-20%, and her work is widely cited. So what's killing the 
     young?


                         WHO ATE THE STELLERS?

       Maybe orca whales. Skippers have plenty of anecdotal 
     reports of orcas attacking Stellers, but the discovery of 
     tags from 14 Stellers in the belly of an orcas that washed 
     ashore in 1992 in Price William Sound constitutes striking 
     scientific evidence that Stellers sea lions, endangered or 
     not, are on the orcas's menu. Researchers at Seward's Alaska 
     Sea Life Center have videotaped orcas charging up the beach 
     at Chiswell Island to snatch Stellers. Studies by Craig 
     Matkin, a recognized authority on Alaska orcas, calculate 
     that 125 marine mammal-eating orcas (known as ``transients'') 
     prey on the endangered western Steller population, and 
     between 10% and 15% of their diet consists of sea lions. 
     According to Matkin, the orcas likely erode the Steller 
     population each year by 3.8%. That's big chunk of NMFS's 
     observed annual decline of 5.2% on average since 1990. Other 
     researchers believe that orcas have been forced to find 
     something besides Stellers to eat, now that the sea lions are 
     scarce. Jim Estes, a researcher at UC-Davis, discovered that 
     orcas have been preying on sea otters with such zeal that 
     between 1993 and 1997 they devoured 76% of the sea otter 
     population at Kuluk Bay, Adak. Unlike fishermen, orcas and 
     ocean climate regimes don't pay much heed to federal 
     regulations. Officials at NMFS would be uncorking a political 
     firestorm--and possible a whole new conservation problem--if 
     they moved to cull killer whales in order to protect 
     Stellers. That leaves NMFS facing intense pressure to crack 
     down on fisheries, even though there's little evidence that 
     this will help.


                          let's test the cure

       To Ken Stump, a consultant to Greenpeace who is credited as 
     the architect of the environmentalists' case against NMFS, 
     the circumstances look like a clear mandate. Scientific 
     uncertainty should not mean inaction, he contends. ``I'd be 
     the first to say that we need more research, but in the near 
     term we aren't going to get any closer to the truth,'' he 
     says. ``In light of the available information, there is no 
     good justification for letting the fisheries pack it in in 
     critical habitats. It is eminently reasonable and 
     precautionary to reduce the impacts of these fisheries while 
     further research continues. It's the one thing we have any 
     control over.''
       With its inconsistent and fumbling legal defense, NMFS gave 
     Judge Zilly little choice but to agree with Stump. Someday, 
     the result probably will be construed as a grand experiment: 
     Let's see if fishing less helps the sea lions. Yet the trawl 
     injunction is anything but scientific. Scientists have 
     insisted for years that barring trawlers from designated 
     critical habitat forecloses any chance of learning whether 
     they really do starve out the animals. That's because the 
     strategy fails to establish ``control'' zones where fishing 
     is allowed inside critical habitat for comparison to similar 
     zones where fishing is prohibited. As the council's 
     Scientific and Statistical Committee put it in September, it 
     would be helpful ``to open some rookeries to controlled 
     fishing in connection with observation on the foraging of 
     Steller sea lions in the area.'' Calling for a more ``science 
     based'' process, the committee observed that fishery managers 
     can have no confidence they have done their job fairly or 
     well.
       According to the committee, ``The only way out of this 
     morass is to design a research and management plan that tests 
     hypotheses related to the Steller sea lion decline and 
     increases the understanding of the potential interactions 
     between groundfish fisheries and Steller sea lions.''
       Whether that can happen ultimately depends upon the courts 
     and, perhaps, Congress. Either way, the environmental 
     litigants in the sea lion case probably would have to sign 
     off on such a research plan. So far that doesn't look likely.
       In conversation, Stump bristles at the mention of Andrew 
     Trites, a scientist who admits he started years ago with the 
     assumption that fishing must be to blame for the Steller's 
     decline but found evidence of other causes instead. In print 
     (Pacific Fishing, October 2000, page 6), Stump rails bitterly 
     against the view that natural causes may account for the 
     Steller's decline. In meetings in Alaska, he publicly taunts 
     Dickie Jacobson, the mayor of Sand Point, Alaska, who says 
     Stump's ``eminently reasonable'' solution puts his whole 
     community at risk and could spell ``the end of the Eastern 
     Aleut world.''
       Stump has good reason to be threatened by such 
     possibilities. He and his allies have scored their legal 
     triumph by exploiting a wide gap in the available science; 
     ignorance is literally their opportunity. They're laughed off 
     requests to help pay for the research necessary to find out 
     what's really killing sea lions. Little wonder. Any genuine 
     scientific test of trawl closures carries a risk for them: 
     Having vanquished trawlers from critical habitat and 
     successfully divided the fishing industry against itself, why 
     should the victors want to learn whether they picked the 
     wrong cure for sea lions?

                          ____________________