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                                                                                                                                                                              u.S Departmenlot Energy
                                                                                                                                                                              Bonn ville Power Administration
                Impact of Redd Loss at Vernita, Bar on                                                                                                                        Divistoon ot Fish & W00ide
                                                                                                                                                                              Fist7ofies Posearch
                Hanford Reach Chinook Salmon Production                                                                                                                         111silt"le
                                                                                                                                                                              School ot Fistierfos

                                                                                                                                                                              October 1988

                                                                                 AM IPA,

                                                                                                                                                                                Final
                                                                                                                                                                                Report
                                                                                                                                                                                1988

                This report was funded by the Bonneville Power Administration (BPA),
                U.S. Department of Energy, as part of BPA's program to protect, mitigate,
                and enhance fish and wildlife affected by the development and operation
                of hydroelectric facilities on the Columbia River and its tributaries. The
                views in this report are the author's and do not necessarily represent the
                views of BPA.

                For copies of this report, write to:

                                      Bonneville Power Administration
                                      Division of Fish and Wildlife - PJ
                                      P.O. Box 3621
                                      Portland, OR 97208

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     1@ :AUTHOR: Rogers, Donald E.
        :TITLE:   Impact of redd loss at Vernita Bar on Hanford Reach chinook salmon
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                                IMPACT OF REDD LOSS AT VERNITA BAR ON HANFORD

                                       REACH CHINOOK SALMON PRODUCTION

                                              FINAL REPORT 1988

                                                 Prepared by

                                         D.E. Rogers and R. Hilborn
                                        Fisheries Research Institute
                                             School of Fisheries
                                          University of Washington
                                             Seattle, WA 98195

                                                                    P"Pe-rty Of CSC Library

                                                Prepared for

                                        Robyn MacKay, Project Manager
                                          U.S. Department of Energy
                                       Bonneville Power Administration
                                        Division of Fish and Wildlife
                                                P.O. Box 3621
                                             Portland, OR 97208
                                             Project No. 87-413
                                       Contract No. DE-AM79-87BP35885

                                                October 1988

                                                                  DEPARTMENT OF COMMERCE NOAA
                                                             COASTAL SERVICES CENTER
                                                             2234 SOUTH HOBSON AVENUE
                                                            CIA@LESTON , SC 29405-2413

                                                               TABLE OF CONTENTS

                                                                                                                                    Page
                      LIST OF TABLES            ................................................................................
                      LIST OF FIGURES             ..............................................................................
                      INTRODUCTION              ..................................................................................       1
                      DATA SOURCES                  .................................................................................    2
                      STATUS OF THE STOCKS                   ....................................................................        3
                      STOCK AND RECRUITMENT                      ................................................................        5
                           In River Retum-1962-1983 Broods                  ......................................................       5
                           Adjusting for Ocean Fishing Mortality             .....................................................       6
                           Utility of Stock Recruitment Data for Hanford Reach Chinook                     .........................     6
                      HABITAT AVAILABILITY AND UTILIZATION                                     ...........................................7
                           Impacts of Redd Loss         ........................................................................         7
                      CONCLUSIONS               ..................................................................................       9
                      REFERENCES            ....................................................................................         10

                                                                     LIST OF TABLES

                       Table                                                                                                               Page
                        1 . Annual commercial and sport catches of chinook salmon in millions of fish                       ...........       11
                        2.   Annual commercial and sport catches of coho salmon in millions of fish                         ...............   12
                        3.   Annual commercial and sport catches of sockeye salmon in millions of fish                      ...........       13
                        4.   Annual commercial and sport catches of pink salmon in millions of fish                      ...............      14
                        5.   Annual commercial and sport catches of chum salmon in millions of fish                       ..............      15
                        6.   Inriver runs of Columbia River chinook in 1,000s                 .........................................       16
                        7.   Major fall chinook escapements and the coastal catches for California                    ..................      17
                        8.   Escapements and returns for Nushagak springs and upriver Columbia
                             fall chinook stocks      .............................................................................           18
                        9.   McNary fall chinook; escapements, inriver returns, and smolts released
                             and transported      .................................................................................           19
                       10.   Annual fall chinook salmon counts in thousands, 1964-1987                           ............................ 20
                       11.   Chinook salmon redd counts in the Hanford Reach and the McNary and
                             Hanford escapements               ..........................................................................    .21
                       12.   Estimates of total recruitment for McNary fall chinook adults                        ............................ 22

                                                                  LIST OF FIGURES

                       Fig.                                                                                                           Page
                       1 .  Annual catches of North American salmon by region, 1971-1987                     ......................     23
                       2.   Annual runs of chinook salmon for six North American stock complexes,
                            1971-1987      ......................................................................................       24
                       3.   Escapement-return relationships for Nushagak spring chinook salmon and
                            upriver Columbia fall chinooks (McNary)             ...................................................     25
                       4.   Inriver return and return per escapement regressed on numbers of hatchery
                            smolts released and numbers collected at McNary and transported downstream,
                            1972-1983 brood years         ........................................................................      26
                       5.   Hanford Reach chinook salmon spawner distribution                        ...................................... 27
                       6.   Escapement-return relationships for McNary fall chinook salmon (excluding
                            jacks); inriver returns (left)-and total returns, including ocean catches (right)              .........    28

                                                            ABSTRACT

                       In this report, we examine the effect on chinook salmon production within the Hanford Reach
                   of redd loss at Vernita Bar. The current target escapement of 40,000 chinook past McNary dam
                   has no real biological justification because the wrong data were used in the analysis and the
                   methods used are now known to be very unreliable for the type of data available. The escapement
                   that maximizes MSY may be lower than 40,000, or much higher, and reliable estimates of
                   optimum escapement are unlikely to be available for several more years.

                       If the optimum escapement is truly 40,000 (or less), then loss of a few hundred redds on
                   Vernita Bar would have no detrimental, and possibly beneficial consequences on total chinook
                   production from the Hanford Reach, so long as escapements are in excess of 40,000. If the
                   optimal escapement is actually much higher (60,000+), the biological cost of redd loss when
                   escapements are in excess of 40,000 would be about two fish in the adult return for every redd
                   lost. So long as escapements exceed 40,000, the issue of redd loss at Vernita Bar is simply a
                   question of losing a few dozen or hundred adult fish in the next brood and is not an issue of stock
                   conservation.

                                                                    iv

                    IMPACT OF REDD LOSS AT VERNITA BAR ON HANFORD REACH
                                           CHINOOK SALMON PRODUCTION

                                                           Introduction
                       The last major naturally spawning stock of chinook salmon in the Columbia River is located in
                    the Hanford Reach between Priest Rapids and McNary dams. This race of fall chinook salmon
                    (also called "upriver brights") spawns throughout the 90 km of the reach; however, one spawning
                    area of about 6 km, Vemita Bar, has special management significance.
                       In April 1976, low discharges from Priest Rapids Dam over a period of 32 hours caused heavy
                    mortalities of emergent fry on Vernita Bar. This prompted regulations on minimum discharges
                    from Priest Rapids dam to protect all but a very few redds on the bar and a study of the effect of
                    flow on redd distribution during 1978-1983. The study showed that management of discharges
                    during the fall spawning period could ease the subsequent minimum flow requirements for
                    incubation and emergence (Chapman et al 1986). Nevertheless, there remained a conflict between
                    power needs and fish needs that was largely resolved in favor of fish needs partly because spawner
                    abundance was at or below that desired by fisheries management. In 1987, the number of
                    spawners in the Hanford Reach was about three times greater than the "goal" and this raised the
                    question of whether the same flow requirements for redd protection on Vernita Bar were necessary
                    or even desirable.
                       The purpose of this report is to assess the impact of flow regulation at Priest Rapids dam on
                    production of chinook salmon in the Hanford Reach of the Columbia River. This analysis is based
                    upon data available at the time of the work (Nov. 87-Mar. 88), does not involve any new data
                    collection, and is intended primarily as an assessment of the current state of knowledge of the
                    problem by independent university researchers.
                       Given the data available, it is not possible to quantitatively assess the impact of Priest Rapids
                    release patterns on chinook production. There are numerous possible hypotheses about the
                    relationship between habitat availability, spawning stock size, flows and survival; and the existing
                    data do not allow us to determine'which of these hypotheses are correct. What we will do is
                    examine the status of the stocks and then discuss the alternative hypotheses, the extent to which
                    the data are consistent with the hypothesis, and the impacts of flow variation on chinook
                    production if the hypothesis was true. The alternative hypotheses can be divided into two basic
                    groups; those built around an underlying stock recruitment model, and those described as habitat
                    based production relationships.

                                                           Data Sources
                       Very little of the statistics on the Hanford Reach chinook salmon stocks is published in the
                   literature; instead, is is available mainly in project reports or in agency files. We relied on Mr.
                   Mike Dell (Grant County P.U.D.) for recent (through 1987) escapement estimates (dam counts),
                   aerial survey counts and juvenile releases. Escapement and return statistics (in-river catch plus
                   escapement by age class) were available from the Washington Department of Fisheries for only
                   upriver brights combined, i.e. all fish above McNary. Estimates of annual runs since 1971 for
                   major stock complexes in the Columbia River and some other Pacific coast areas were obtained
                   from the Pacific Fishery Management Council (Review of 1987 Ocean Salmon Fisheries, Feb
                   1988). Earlier historical run statistics for the Columbia River are available in Kom (1977).
                       To provide some perspective on -the fluctuations in abundance of Columbia River chinook
                   salmon,' we utilized escapement and return data for the Nushagak River stocks presented in
                   Nelson (1987) and trends in historical salmon catches from the North Pacific as reported in Fredin
                   (1980), International North Pacific Fisheries Commission (INPFC) Secretariat (1979), annual
                   INPFC Statistical Bulletins, and INPFC as well as other agencies for 1985-1987 preliminary
                   statistics.

                                                                   2

                                                          Status of the Stocks
                        Commercial fisheries on North American salmon developed in the late 1800s and early 1900s.
                    By about 1920, most of the major stocks were under extensive exploitation and there followed a
                    thirty-year period of sustained production and then a decline in the early 1950s. Relatively low
                    production continued through the mid-1970s, but since then salmon production has equalled or
                    exceeded earlier historical production (Rogers 1987 and Tables 1-5). Columbia River fall chinook
                    salmon (presumably including the Hanford Reach) had undergone similar changes in abundance
                    through the early 1970s (Kom 1977); although for chinook salmon stocks combined (California to
                    southeastern Alaska), the catches from the 1920s to 1970s were rather stable as declines in natural
                    stocks were replaced by hatchery production (Rogers and Salo 1985).
                        Catches of chinook salmon from California[ to southeastern Alaska (southern region) declined
                    in the 1980s in sharp contrast to catches of the other species and especially catches in the northern
                    region, i.e. upper Gulf of Alaska and Bering Sea coast or central and western Alaska (Fig. 1).
                    Since the decline in the early 1980s there has been a modest increase in chinook production
                    coastwide and an exceptional increase in the abundance of Columbia River fall chinook salmon
                    (inriver) relative to the other major chinook salmon stocks (Fig. 2 and Tables 6-7). However, it is
                    difficult to interpret changes in the inriver runs because a significant proportion of Columbia River
                    chinook salmon are caught in ocean fisheries mixed with stocks from other rivers. Perhaps the
                    inriver runs increased partly because ocean catches of Columbia fall chinook salmon decreased.
                        The upriver fall chinook salmon of the Columbia (all those originating above McNary) have
                    undergone some recent changes in abundance that are similar to the changes observed in the
                    Nushagak River stock of Bristol Bay, Alaska from 1966 through 1983. Both stocks experienced
                    large increases in returns with relatively little change in escapement (Fig. 3 and Table 8). In the
                    Nushagak case, the larger returns from the 1975-1977 broods encouraged management to increase
                    escapements (1978-1983). This apparently was a mistake, since the larger escapements (more than
                    double the prior goal) have been very poor producers. The McNary escapements since 1985 have
                    also been more than double the management goal and may likewise produce poorly if the goal of
                    40,000 adults (ages 3 and older) was approximately correct. Unfortunately, past and future
                    escapements may have little measurable impact on future runs because the upriver fall chinook are
                    not managed as a natural stock.
                        Attempts to artificially enhance the production of chinook salmon in the Hanford Reach have
                    gone on for over 20 years-first as a spawning channel that apparently failed and now as a
                    hatchery that is apparently succeeding. The recent large inriver returns and the relative production
                    (return per escapement) of upriver fall chinook salmon are highly correlated with the number of
                    hatchery smolts released (Fig. 4 and Table 9). In addition to the trend of increasing hatchery
                    releases there has been an increase in the collection and transportation of smolts past McNary, and
                    this is also correlated with recent returns and relative production. These apparently successful
                    enhancement techniques for upriver fall chinook salmon may not be so successful for the natural
                    spawners in the Hanford Reach and, at the very least, make it very difficult to evaluate the impact
                    of flow regimes on natural production from the Hanford Reach or Vemita Bar.
                        The escapements of chinook salmon to the Hanford Reach (natural spawners) are estimated by
                    counts at McNary minus counts at Priest Rapids, Ice Harbor and volunteers--hatchery or spawning
                    channel (Table 10). Jacks (precocious adults, age 2) are counted separately from older adults
                    based on length; otherwise, age compositions were not available. After 197 1, when Priest Rapids
                    counts declined, the Hanford Reach received an average of 75% of the older adults and 80% of the
                    jacks counted past McNary (Fig. 5A). The differences in adult and jack counts may be caused by
                    different length criteria at the dams and hatchery rather than a real difference in age composition.
                    Most noteworthy was the relatively low percentage of adults (62%) in the Hanford Reach in 1987
                    which was caused by a greater increase in the Priest Rapids and hatchery counts than in the natural
                    spawners in the Reach.

                                                                        3

                      The distribution of spawners within the Hanford Reach can be examined with the aerially
                   surveyed redd counts by Watson (1970). The redd counts on Vemita Bar ranged from 32% to
                   42% of all redds counted in the Hanford Reach with two exceptions (Fig. 5B and Table 11).
                   Aerial surveys can detect redds only in relatively shallow water (about 3m) and most spawning
                   probably occurs in deeper water (M. Dell, personal communication). Mr. Watson changed survey
                   methods in 1981 (counted only at low water) and thus counts increased relative to the number of
                   spawners present.
                      After 198 1, when escapements were  at a low point, there were successive increases in adult
                   counts past McNary, from 21,000 to 157,000. There were also successive increases in the redd
                   counts on Vernita Bar, but these increases were small relative to increased counts in other areas of
                   Hanford Reach (Fig. 5D-Q and small relative to the increase in escapement past McNary.
                   Escapements increased seven-fold between 1981 and 1987, whereas Vemita Bar redd counts only
                   increased 52%. Thus, the importance of Vernita Bar as a spawning location appears to decline as
                   the escapement has increased.

                                                                 4

                                                     Stock and Recruitment
                       The tradition in consideration of Hanford Reach chinook has been stock recruitment analysis.
                   The current 40,000 (age 3+) escapement goal past McNary was derived from such an analysis in
                   1982, and our understanding is that efforts are now underway to update the data base and
                   reevaluate the escapement goal. The 40,000 escapement goal now in place was derived in a
                   document by the Technical Advisory Committee, dated July 1982. It was recognized in their
                   report that the estimate of 40,000 was "tenuous". Nevertheless, the 40,000 number has become an
                   important figure in both the Columbia, and chinook management of the entire Pacific Coast.
                       Given our current understanding of the power of stock recruitment analysis, we can now say
                   with hindsight that there is little if any biological justification for this number. The following
                   specific points need to be considered:
                     1 . The data used in the analysis did not consider ocean catches.
                     2.  At the time of the analysis, few scientists were aware of the serious biases in stock
                         recruitment data that result from imperfect spawning escapement data (Walters and Ludwig,
                         1982). The imprecision of the estimates of how many fish actually spawned in the Hanford
                         reach (as opposed to how many passed McNary dam), and the very narrow range of
                         spawning escapements represented in the data, preclude a reliable estimate of the optimum
                         spawning stock. It may easily be anywhere above 20,000, it could be several hundred
                         thousand, or it could be 40,000. The data available in 1982 were insufficient to make any
                         determination of the expected production of spawning stocks from 40,000 and up.
                     3.  Even in the absence of inaccuracy in spawning escapements, stock recruitment analysis of
                         time series data will usually be biased towards a too low estimate of optimum escapement
                         (Hilbom and Starr, 1984; Walters, 1985). Again this problem was not known in 1982, but
                         we now know to be doubly distrustful of stock recruitment analysis from data with a very
                         narrow range of spawning stock sizes.
                     4.  Although the exact method used to fit the models is not described in the 1982 document, it is
                         almost certain that they did not consider the effect of stochasticity on the optimum es-
                         capement. Hilbom. (1985) showed that the optimum escapement is always higher than that
                         predicted by the simple fit of the Ricker model. This is not a major effect, but underlines the
                         fact that while the Ricker model may have been fit to the data in 1982, there was little
                         understanding of the statistical basis of estimating optimal escapement from such data.

                                               In River Retum-1962-1983 Broods
                       Data are now available on spawning stock through 1987 and the returns from the 1983 brood
                   (4 year olds). Using the McNary dam counts of adults (age 3+) as the estimated spawning stock,
                   we obtain the stock recruitment graph shown on the left side of Figure 6. Note that this still does
                   not include any ocean fishing mortality.
                       If we fit the Ricker stock recruitment curve, we obtain optimal escapement of approximately
                   34,000 fish. More importantly the stock recruitment curve is extremely flat over the observed
                   range of spawning stock sizes. All the problems mentioned in the previous discussion of the 1982
                   estimate are valid for this analysis. There simply has not been enough variation in spawning stock
                   to understand the underlying relationship. However, if one were to believe this analysis, it would
                   suggest that increases in escapement over 40,000 actually reduce total production, and therefore
                   any mortality on redds caused by flow variation at Priest Rapids dam, would likely be beneficial
                   to total production. These data suggest that between 30 and 60 thousand adults,there is some
                   density dependent mechanism that limits total productivity, and additional spawners, or additional
                   redds will not increase total production. In fact, beyond the 60,000 escapement, the total
                   production decreases significantly, and the large spawning stocks of 1985-1987 would be expected
                   to have very poor returns.

                                                                     5

                      Anyone who believes in the stock recruitment analysis would therefore accuse the management
                   agencies of serious mismanagement during the 1985-1987 ppriod, and any mortality of spawners
                   or redds would have been thought to be beneficial! There would be absolutely no concern about
                   redds being killed on Vernita bar when escapements were over 40,000.

                                             Adjusting for Ocean Fishing Mortality
                      One of the major failings of the 1982 stock recruitment analysis was that it did not consider the
                   ocean catch as part of the production. - While from a very narrow up-river Columbia perspective,
                   all fishing mortality outside of the river may be considered as "natural" mortality, if we really want
                   to maximize the benefits from the Hanford Reach we should include estimated ocean catch as part
                   of the recruitment.
                      We have made a very preliminary attempt to do this using the estimated ocean fishing mortality
                   on the.1975 to 1983 broods of Priest Rapids Hatchery fall chinook from an analysis performed by
                   the International Pacific Salmon Commission (IPSC), chinook technical committee. Table 12
                   shows the data-used. We have included an estimate of the 1983 brood year return, since this is the
                   single most informative spawning stock size in the data sequence, and it is clear, despite the fact
                   that the age 5 returns are not yet available that the brood year production was very good.
                      These data show increasing recruits per spawner with larger spawner stock sizes, and therefore
                   the Ricker curve gets steeper with increasing stock sizes (right side of Figure 6). The estimated
                   optimal escapement is therefore infinite! This is, of course unbelievable, however it does suggest
                   the the optimal stock size (for MSY) may be considerably greater than 40,000.

                               Utility of Stock Recruitment Data for Hanford Reach Chinook
                      Until the brood year returns are available for the large spawning stocks of 1985-1987, there is
                   little to be learned from the analysis of stock recruitment data for this population. A pressing need
                   is for a better data base: there appears to be no consensus on what numbers to use as Hanford
                   Reach spawners or exactly what to include as brood year returns. It is possible that if a better,
                   carefully constructed data base was available, a stock recruitment pattern would appear from the
                   1962-1983 data, but certainly the important data will be those that come from the broods of the
                   large spawning stocks now at sea.
                      Unfortunately, the interpretation of the next few data points will always be ambiguous. If the
                   returns are large, then statistical fits will suggest that much larger spawning stocks are desirable; if
                   returns are poor then the optimum escapement would appear to be in the 30,000 to 40,000 range.
                   It is also quite possible that some of the returns will be large and some small. Someone will
                   always be able to argue that the good returns (if they are good), or the poor returns (if they are
                   poor) were caused by oceanic conditions and not representative of the "average" stock recruitment
                   relationship. The only hope for a truly unambiguous answer is 5 or more data points roughly
                   grouped together. Experience with salmon spawner recruit data suggests this is not particularly
                   likely.
                      Interpretation of the cost of redd mortality due to flow variation on Vernita Bar, will be quite a
                   bit more straightforward. If the next few broods produce large returns, and the optimum
                   escapement is raised to 60,000 or even 150,000, then the loss of dozens, or even hundreds of
                   redds on Vernita Bar would be of no measurable or significant consequence to the Hanford stock,
                   so long as escapements are 40,000 fish or more. If the next few broods produce small returns,
                   then the optimum escapement will be assessed to be 40,000 or less, and loss of redds when
                   escapements are over 40,000 would be of no significance (downward slope of recruitment curve).

                                                                   6

                                             Habitat Availability and Utilization
                        An alternative approach to understand the relationship between spawners and subsequent
                    production is to explicitly consider the relationship between habitat available, spawner utilization,
                    redd survival, fry production and downstream migration. The key components of such an analysis
                    would include:
                      1. A description of habitat availability under different flow levels.
                      2. A description of how the spawners distribute themselves over the available habitat.
                      3. A method for calculating the survival rate of redds and juveniles under different flow
                          regimes.
                        From the available documentation, it appears the parts I and 3 could be accomplished from
                    existing information. Part 2 would require some assumptions about the preference of spawning
                    females for different gravel sizes and flow regimes.
                        Much of the current controversy over Vernita Bar spawning is the increasing number of redds
                    higher up on the Bar. It is generally a ccepted among salmon biologists that when spawning
                    densities increase, some spawners are forced out of preferred habitat into marginal habitat.
                    Marginal habitat is commonly thought of as either less desirable substrate or higher probability of
                    redd loss at low water. Such use of marginal habitat is often cited as one of the mechanisms for
                    the decreasing slope of the spawner recruit curve at higher spawning densities.
                        Therefore, it is to be expected that as the stock approaches and exceeds its optimum spawning
                    stock, more redds should appear higher up on Vernita Bar, and almost certainly in less desirable
                    habitats throughout the entire Hanford Reach. The value of the redds to chinook production is
                    clearly much less than redds deposited lower down on Vernita Bar for two reasons:
                      I . Given that there are more spawners, each redd constitutes a small proportion of the total
                          stocks productive potential.
                      2.  Eggs deposited in marginal habitat have a lower expected survival rate than eggs deposited in
                          prime or preferred habitat. (It should be noted that the redds higher up on Vernita Bar may
                          be considered marginal to some extent because of the flow regime which is under human
                          control, and given a very high release level may produce good survivals).

                                                         Impacts of Redd Loss
                        The biological question associated with alternative flow regimes in the Hanford Reach is what
                    is the likely impact on chinook production of alternative outflows from Priest Rapids dam. It is
                    accepted by all parties that sustained drops in flow level will dry and kill redds, on Vernita Bar, and
                    the number of redds killed depends on where spawning occurs, and the duration of redd drying.
                        When spawning stocks are above 40,000 (and most likely even below that level), we are not
                    dealing with an issue of stock survival or long term conservation, we are simply dealing with the
                    trade off of letting fish spawn now to produce more fish in tile future. The biological definition of
                    MSY is the level of spawning -s-Cock at which the stock can be expected to produce on average the
                    maximum harvestable surplus. At this level, the last pair of spawning chinook (that is the
                    20,000th pair if 40,000 is the MSY optimum escapement), can be expected to produce exactly 2
                    adults in the return. Thus the value of adding, or losing a fish in the escapement is exactly what
                    fish are worth in the catch (when the stock is at MSY escapement). If the spawning stock is
                    greater than MSY escapement then the value of spawners (or redds) is actually less than the value
                    in the catch.
                        ne loss of 250 redds from a spawning stock of over 100,000 fish could not possibly produce
                    measurable or significant effects on the resultant production and the economic cost of such loss
                    would, at the maximum be the maximum recruits per spawner times the 500 spawners involved in

                                                                     7

                   the redds. If we accept that the spawning stock is at or above the optimum escapement for MSY,
                   then the economic cost of such redd loss would be at most the value of the 500 spawners to the
                   fishery.

                                                                   8

                                                             Conclusions
                       There is great uncertainty about the relationship between the number of chinook spawning in
                    the Hanford Reach and the resultant production of adults. The currently used optimum escapement
                    number of 40,000 past Mc  'Nary is based on the wrong type of data and analyzed without a due
                    appreciation of the problems in stock recruitment analysis. The true optimum escapement for MSY
                    may be below or possibly far above 40,000.
                       Concern about the impact of killing redds on Vernita Bar is certainly real. However, it must be
                    recognized that when spawning stocks are anywhere near or above the optimum escapement, the
                    impact of redd mortality is simply a reduction in the expected future production, and that this
                    impact, even in the worst scenarios constitutes less than 1% of the total stock. If the stock is truly
                    above the MSY escapement then it is possible that redd loss would actually benefit total
                    production. The biological cost of redd loss when escapements are high (above 40,000) cannot be
                    precisely determined, but will be approximately two fish (one male and one female) per redd lost.
                       In the process of reviewing the available information on the Hanford Reach chinook, it became
                    quickly clear that the available data had not been assembled in a particularly useful fashion. ne
                    following data would have been highly desirable, and we were surprised that the agencies had not
                    produced it.
                     1 . An agreed upon set of data giving brood by brood Hanford Reach spawners, and inriver
                         returns by age. We found several different sets of spawner and return data, with different
                         measures used as indices of both spawners and returns.
                      2. Estimates of the ocean catch of Hanford Reach chinook. These data are essential for a proper
                         stock recruitment analysis.
                      3. A table of the area available for chinook spawning within Hanford Reach under different
                         flow levels, and how much of each area would be dried out under flow reductions. The data
                         should be stratified by bottom type, and water depth, as well perhaps as cfs at the gavel
                         surface.
                       We would suggest that the state, tribes and power agencies get together an agreed-upon data
                    base prior to any discussion of optimal escapement, or regulation strategies.

                                                                    9

                                                           References

                   Chapman, D.W., D.E. Weitcamp, T.L. Welch, M.B. Dell and T.H. Schadt. 1986. Effects of
                      river flow on the distribution of chinook salmon redds. Transactions of the American Fisheries
                      Society 115:537-547.
                   Fredin, R.A. 1980. Trends in North Pacific salmon fisheries. Pages 59-114 in W.J. McNeil and
                      D.C. Himsworth, editors, Salmonid Ecosystems of the North Pacific. Oregon State
                      University Press, Corvallis, OR.
                   I-Elbom, R. 1985. Simplified calculation of optimum spawning stock size from Ricker's stock
                      recruitment curve. Canadian Joumal of Fisheries and Aquatic Sciences 11: 1833-1834.
                   I-Elbom, R. and P.Starr. 1984. Making stock recruitment analysis work. Pages 227-244 in
                      P.E.K. Symons and M. Waldichuk, editors, Proceedings of the Workshop on Stream
                      Indexing for Salmon Escapement Estimation, West Vancouver, B.C., 2-3 February 1984.
                      Canadian Technical Report Fisheries and Aquatic Sciences.
                   I?*4PFC Secretariat. 1979. Historical catch statistics for salmon of the North Pacific Ocean.
                      Intemational North Pacific Fisheries Commission Bull. 39. 166 p.
                   Kom, L. 1977. Information on Columbia River salmon runs and fisheries.Intemational North
                      Pacific Fisheries Commission Bull. 36:1-14.
                   Nelson, M.L. 1987. History and management of the Nushagak chinook salmon fishery. Alaska
                      Dept. Fish and Game Bristol Bay Data Report 87-1. 137 p.
                   Rogers, D.E. 1987. Pacific salmon. Pages 461-476 in D.W. Hood and S.T. Zimmerman,
                      editors, The Gulf of Alaska. U.S. Govemment Printing. Washington D.C.
                   Rogers, D.E. and E.O. Salo. 1985. Trends in natural and hatchery production of chinook
                      salmon. NOAA Technical Report NMFS 27:39-43.
                   Walters, C.J. 1985. Bias in the estimation of functional relationships from time series data.
                      Canadian Joumal of Fisheries and Aquatic Sciences 42:147-149.
                   Walters, C.J. and D. Ludwig. 1982. Effects of measurement errors on the assessment of stock-
                      recruitment relationships. Canadian Joumal of Fisheries and Aquatic Sciences 38:704-710.
                   Watson, D. 1970. Fall chinook salmon spawning in the Columbia River near Hanford 1947-
                      1969. Battelle Pacific Northwest Laboratories, BNWL-1515, UC-48, Richland, Washington.

                                                                 10

                      Table 1. Annual commercial and sport catches of chinook salmon in millions of fish.

                                                  North America                                    Asia
                                                                          SE C&W
                                  Calif.-Wash. British Columbia         Alaska Alaska       Japan    USSR
                         Year    Comm. Sport Comm. Sport               Comm. Comm. High seas         Coastal
                        means
                       1921-50     1.9     --       0.6       --          0.5     0.2       <0. 1      0.1
                       1951-70     1.4     0.4      1.0       0.1         0.3     0.2       0.2        0.1

                         1971      1.3     0.6      1.6       0.1         0.3     0.3       0.3        0.2
                         1972      1.3     0.6      1.6       0.2         0.3     0.2       0.4        0.2
                         1973      2.2     0.7      1.4       0.2         0.3     0.2       0.3        0.2
                         1974      1.5     0.7      1.5       0.3         0.3-    0.2       0.5        0.2
                         1975      1.7     0.8      1.4       0.4         0.3     0.2       0.3        0.2.
                         1976      1.6     0.6      1.5       0.5         0.2     0.3       0.5        6.2
                         1977      1.7     0.6      1.5       0.4         0.3     0.3       0.3        0.3
                         1978      1.3     0.5      1.4       0.5         0.4     0.4       0.3        0.3
                         1979      1.5     0.5      1.3       0.4         0.4     0.5       0.3        0.3
                         1980      1.4     0.4      1.2       0.4         0.3     0.4       0.9        0.1

                         1981      1.2     0.4      1.1       0.3         0.3     0.6       0.3        0.1
                         1982      1.6     0.4      1.2       0.2         0.3     0.6       0.3        0.1
                         1983      0.7     0.4      1.0       0.2         0.3     0.5       0.3        0.2
                         1984      0.8     0.3      1.0       0.4         0.3     0.4       0.2        0.2
                         1985      0.9     0.4      0.9       0.3         0.2     0.5       0.2        0.2
                         1986      1.5     0.4      0.8       0.2         0.2     0.3       0.1        --
                         1987      1.7     --       0.9       0.2         0.3     0.4       0.1

                     Table 2. Annual commercial and sport catches of coho salmon in minions of fish.

                                                 North America                            Asia
                                                                    SE      C&W
                               Calif, Wash.     British Columbia Alaska    Alaska      Japan    USSR
                       Year   Comm. Sport      Comm. Sport        Comm.    Comm.     High seas  Coastal
                      means
                     1921-50    1.8      --      2.2      --        1.7      0.8        0.3       1.7
                     1951-70    1.8     0.6      3.4     0.1        1.3      0.6        2.5       1.2

                       1971     4.1     1.2      4.8     0.4        0.9      0.5        2.8       1.3
                       1972     2.3     0.9      3.4     0.3        1.5      0.3        3.0       0.5
                       1973     3.0     0.8      3.5     0.4        0.8      0.6        4.8       0.7
                       1974     4.1     1.2      3.7     0.8        0.6      0.6        4.6       1.2
                       1975     2.8     1.0      2.3     0.5        0.4      0.6        3.9       1.2
                       1976     5.6     1.7      3.7     0.4        0.8      0.6        3.6       1.2
                       1977     2.2     0.9      3.3     0.7        0.9      0.8        1.8       1.4
                       1978     2.4     1.0      3.4     1.1        1.7      1.1        3.1       0.7
                       1979     2.5     0.8      3.6     0.4        1.1      2.0        1.5       1.3
                       1980     2.3     0.8      3.4     0.6        1.1      2.0        1.9       0.8
                                        0.7
                       1981     2.0     0.7      2.8     0.4        1.4      2.1        1.9       1.1
                       1982     2.5     0.6      3.2     0.5        2.1      4.0        2.4       1.2
                       1983     1.4     0.7      4.1     0.4        2.0      1.7        1.4       1.1
                       1984     1.2     0.4      3.6     0.4        1.9      3.5        1.7       1.5
                       1985     1.7     0.6      3.0     0.7        2.4      3.1        0.9       1.8
                       1986     2.3     0.7      4.9     0.6        2.9      2.8        0.5       --
                       1987     2.5     0.6      3.3     0.7        1.6      1.9        0.5

                                                            12

                       Table 3. Annual commercial catches of sockeye salmon in millions of fish.

                                                 North America                                Asia
                                     Washington Southeast        Central Western        Japan      USSR
                           Year     Brit. Colum.     Alaska      Alaska     Alaska    High seas Coastal
                          means
                         192i-50         5.5           1.7         6.0        13.8       2.3         7.9
                         1951-70         6.3           0.9         3.4        8.4        9.8         1.5

                           1971          9.4           0.6         3'6        9.0        6.6         0.8
                           1972          4.8           0.9         3.1        2.6        6.9         0.3.
                           1973          10.1          1.0         2.5        0.9        5.9         0.7
                           1974          9.9           0.7         2 * 5      1.6        5.4         0.4
                           1975          4.0           0.2         2.0        5.2        5.2         0.6
                           1976          6.1           0.6'        4.9        6.3        5.8         0.4
                           1977          8.2           1.0         6.0        5.1        2.8         0.7
                           1978          8.6           0.7         6.5        10.8       3.2         1.3
                           1979          7.4           1.0         4.0        23.4       2.9         1.2
                           1980          .3.7          1.1         7.0        25.1       3.2         1.4

                           1981          9.8           !.1         7.7        27.6       3.1         1.4
                           1982          13.0          1.5         10.8       16.8       2.5         1.0
                           1983          5.9           1.6         11.8       39.6       2.5         1.5
                           1984          6.8           1.2         10.6       26.6       1.9         2.2
                           1985          15.1          1.8         10.2       26.1       1.3         3.4
                           1986          12.6          1.4         12.0       18.4       0.9         --
                           1987           --           1.4         16.3       17.4       0.8

                                                                  13

                       Table 4. Annual commercial catches of pink salmon in millions of fish.

                                                    North  America                           Asia
                                  Washington Southeast      Central  We-stem            Japan        USSR
                          Year   Brit. Colum.      Alaska   Alaska    Alaska   'High seas Coastal*   Coastal
                         means
                        1921-50           11.4      28.1      18.3       0.2        4          57       37
                        1951-70           10.4      11.7      13.5       0.8        37         10       36

                          1971            11.0       9.3      14.1       0.1        40         12       39
                          1972            14.2      12.4       3.3       0.2        21         8        14
                          1973             9.1       6.5       3.3       0.1        36         10       50
                          1974             7.4       4.9       3.8       1.2        22         8        23
                          1975             6.0       4.0       8.9         +        34         10       56
                          1976            10.3       5.3      18.3       1.2        16         6        37
                          1977            12.7      13.8      14.7       0.1        24         7        74
                          1978            10.5      21.2      26.5       6.1        10         7        45
                          1979            16.5      11.0      38.4       0.7        17         6        86
                          1980             8.2      14.5      43.1       5.7        15         6        53

                          1981            22.2      19.0      40.5       0.6        18         7        57
                          1982             2.7      24.2      37.4       3.2,       14         6        29
                          1983            25.9      37.5      22.7       0.1        18         6        69
                          1984             7.5      24.7      45.8       5.8        14         6        34
                          1985            24.4      48.9      36.1          +       13         13       61
                          1986            18.0      43.4      30.5       0.5        7          --       --
                          1987               --     10.0      35.9          +       7

                        *Mostly off USSR coast or in Japan Sea, i.e., USSR origin.

                                                                   14

                     Table 5. Annual commercial catches of chum salmon in millions of fish.

                                             North     America                           Asia
                               Washington Southeast    Central    Western           Japan         USSR
                       Year Brit. Colum. Alaska        Alaska      Alaska      I-Eghseas Coastal Coastal
                       means
                      1921-50      5.7        4.8        2.5         0.5            4       13*      14
                      1951-70-     .2.9       2.4        2.9         0.8           16        4       10

                       1971        1.5        1.9        4.3         1.4           17        9       4
                       1972        7.0        2.9        2.7         1.4           22        8       1
                       1973        6.8        1.8        2.1         2.0           16        11
                       1974        2.7        1.7        0.9         2.2           22        12      .2
                       1975        1.3        0.7        1.3         2.3           19        18      2
                       1976        2.7        1.0        2.2         2.7           22        11      .3
                       1977        1.6        0.7        3.4                       12        14      4
                       1978        4.3        0.9        2.6         3.2            7        17      4
                       1979        1.0        0.9        2.3         2.7            6        26      4
                       1980        4.3        1.7        3.6         4.3            6        23      4

                       1981        1.7        0.9        6.8         5.0            6        31      4
                       1982        4.1        1.4        6.9         2.7            7        27      3
                       1983        1.6        1.2        5.3         3.7            6        35      5
                       1984        2.6        4.1        4.4         4.6            6        35      3
                       1985        6.6        2.4        3.7         3.2            4        48      6
                       1986        6.7        2.2        5.7         3.1            3        --      --
                       1987        --         2.6        4.5         3.1            3

                     *Mostly off USSR coast.

                                                            15

                      Table 6. Inriver runs of Columbia River chinook (excluding jacks) in 1,000s.

                                                Fall    stocks                        Spring stocks
                                Upriver       Lower river         Bonneville          Upper    Lower
                        Year   McNary)     Hatchery      Wild   Pool Hatchery          River    River

                        1971       116          181       108              116          146        95
                        1972         87         152        79               46          270        65
                        1973       148          215        49              113          224        84
                        1974         90         154        27               70          100        107
                        1975       112          184        37              184           98        68
                        1976       115          171        15              182           64        81
                        1977         95         165        30              108          138        92
                        1978         85         166        18              100          127        107
                        1979         89         119        33               95           49        69

                        1980         77         106        39               98           53        73
                        1981         67           95       25               86           64        93
                        1982         79         140        13              121           71        107
                        1983         86           88       17               29           56        94
                        1984       131          102        13               48           47        116
                        1985       196          ill        13               33           85        84
                        1986       282          154        24               17          121        91
                        1987       421          346        37                 9         100        131

                      Source: P.M.F.C.

                                                                  16

                      Table 7. Major fall chinook escapements and the coastal catches for California

                                Sacramento an Joaquin Rivers           Klamath River
                                           Escapements              Catch + escapement     Coastal catch
                        Year          Adults       Jacks   Total   Adults Jacks Total      Comm.+sport

                        1971             191         48     239                                    662
                         .1972           100         52     152                                    692
                        1973             228         44     272                                   1015
                        1974             206         29     235                                    649
                        1975             159         36     195                                    683
                        1976             169         24     193                                   .621
                        1977             156         42                                            704
                        1978             137         20     157                                   .710
                        1979             168         58     .226       50      12    62            849
                        1980             156         26     182        44      37    81            673

                        1981             196         66     262        .77     28-  105            670
                        1982.            174     1   52     226        65      39   104            �09
                        1983             122         85     207        58       4    62            357
                        1984             205         64     269        43      -9    52            389
                        1985             304         51    -.-355      59      64   123            521
                        1986             256         33     289        186     42   228            920
                        1987             185         79     264        199     24   223           1070

                      Source: P.M.F.C.

                                                                  17

                      Table 8. Escapements and returns for Nushagak springs and upriver
                                    Columbia fall chinook stocks (in 1,000s).

                                                                McNary Fall Chinook
                       Brood        Nushagak                Run Escape.     Return
                       Year     Run   Escape.  Return           (Age 3+)    (Total) (Age 3+)

                       1966     102       40       98       123       51      151        110
                       1967     165       65     100        164       43      208        137
                       1968     155       70     110        159       49      151        101
                       1969     123       35       49       207       55      142         91
                       1970     144       50     139        177       43      218        175
                       1971     127       40     175        167       49      150         86
                       1972       75      25     229        129       38      147         86
                       1973       72      35     203        212       46      174        118
                       1974     110       70     124        150       35      211        112
                       1975       98      70     399        168       30      197        118
                       1976     168      100     281        214       29      102         52
                       1977     156       65*    473        173       37      119         72
                       1978     255      130     149        136       27        72        48
                       1979     262       95     198        136       31      143        100
                       1980     218      141     107        100       30      219        158
                       1981     356      150     149        110       21      205        155
                       1982     356      147     54+        141       31      403        306
                       1983     313      162                136       49      461+      305+
                       1984     154       81                229       61      335+      145+
                       1985     150       72                507       95
                       1986     122       43                660       113
                       1987     147       84                523       157

                                                               18

                           Table 9. McNairy fall chinook; escapements, inriver returns (all ages), and smolts released
                                      and transported.

                                             McNary fall chinook            Priest Rapids smolt        Smolts collected &
                                                  (in  1,000s)                 releases (in millions)     transported at
                             Brood     Escapement         Return            P.R. hatchery      Other      McNary dam
                               Year (age 3 & older)      (all ages)   R/E        source       sources      (in millions)

                               62                 36             57   1.6
                               63                 27           206    7.6
                               64                 40             93   2.3
                               65                 41           216    5.2
                               66                 51           151    3.0
                               67                 43           208    4.9
                               68                 49           151    3.1
                               69                 55           142    2.6
                               70                 43           218    5.0
                               71                 49           150@   3.1

                               72                 38           147    3.9              0.7       0.1
                               73                 46           174    3.7              2.9       .0.0
                               74                 35           211    6.1              1.3       0.0
                               75                 30           197    6.6              1.9       0.9
                               76                 29           102    3.5              1.3       0.0
                               77                 37           119    3.2              1.5       0.5            +
                               78                 27             72   2.6              1.2       0.0            0.4
                               79                 31           143    4.6              2.7       0.4            0.7
                               .@o                30           219    7.3              4.8       1.7            2.1
                               81                 21           205    9.7              5.5       1.7            1.6

                               82                 31           401    12.9            10.3       6.1            4.2
                               83                 49          461+   9.5+              9.7       11.7           3.9
                               84                 61          335+   5.5+              7.0       0.0            6.4
                               85                 95              --                   6.4       0.0            5.8
                               86                 113                                  7.1       0.0            6.7
                               87                 157                                    --         --          --

                                                                      19

                      Table 10. Annual fall chinook salmon counts in thousands, 1964-1987.

                             McNary Dam       Priest Rapids    Ice Harbor    Volunteers     Hanford Reach*
                      Year   Age 2 Age 3+     Age 2  Age 3+   Age 2 Age 3+    Age 2 Age 3+     Age2 Age 3+

                      1964      18      40         8       7        2      9                       8     24
                      1965      35      41        13       8        4      8                      18     24
                      1966      24      51         9      10        2    13                       12     28
                      1967      30      43         7       5        5    14                       19     24
                      1968      24      49         6       5        5    19                       13     24
                      1969      24      55         8       5        4    14                       13     36
                      1970      18      43         11      5        1      9               1       6     28
                      1971      21      49         4       7        2      9               1      15     32
                      1972      12      38         4       2        2      7               1       6     27
                      1973      27      46         5       5        2      7               2      20     33

                      1974      27      35         3       5        1      2               1      24     26
                      1975      39      30         9       4        1      2                      29     23
                      1976      59      29         5       6        1      1               1      53     22
                      1977      47      37         3       4        1      1               1      44     32
                      1978      17                 2                1      1               1      15     21
                      1979      19      31         3       5        1      1               2      15     23
                      1980        9     30         2       6        1      1               1       6     22
                      1981      12      21         2       4        1      1               1       9     15
                      1982      26      31         4       9        2      2                      20     21
                      1983      25      49         3       8        1      2               1      22     37

                      1984      49      61         5       8        1      2        1      4      42     47
                      1985      112     95         9       12       7      2       13     11      83     70
                      1986      126     113        11      19       3      3        8     11      104    80
                      1987      47      157        5       35       2      7       2      17      38     98

                      *McNary-P.R., I.H. and volunteers

                                                               20

                      Table 11. Chinook salmon' redd counts in the Hanford Reach and the'
                                 McNary and Hanford escapements.

                                   Escapement of age 3+            D. Watson's aerial redd
                                       in 1,000s                       Counts in 100s
                        Year            McNary    ffanford        Vernita Bar Other Hanford

                         64                 40        24                  6             9
                         65                 41        24                  7            11
                         66                 51        28                 13            18
                         67                 43        24                 13            20
                         68                 49        24                 15            21
                         69                 55        36                 15            30
                         70                 43        28                 15            23
                         71                 49        32                 14            22
                         72                 38        27                  1             8
                         73                 46        33                  9            21
                         74                 35        26                  2             5
                         75                 30        23                 10            17
                         76                 29        22                  6            14
                         77                 37        32                  8            24
                         78                 27        21                 10            20
                         79                 31        23                 10            20
                         80                 30        22                  9             6

                         81                 21        15                 21            28
                         82                 31        21                 22            28
                         83                 49        37                 22            31
                         84                 61        47                 23            50
                         85                 95        70                 24            52
                         86                 113       80                 31            52
                         87                 157       98                 32            54

                      Survey method changed in 19 8 1.

                                                                21

                        Table 12. Estimates of total recruitment for McNary fall chinook adults (age 3+).

                                      Spawning        Inriver         Ocean
                           Brood         Stock      Recruitment      Harvest       Total
                            Year     (Escapement)     (Return)        Rate      Recruitment     R/S

                            1975          30             118          0.47          224         7.5
                            1976          29             52           0.53          110         3.8
                            1977          37             72           0.35          Ill.        3.0
                            1978          27             48           0.19          60          2.2
                            1979          31             100          0.29          141         4.5
                            1980          30             158          0.44          281         9.4
                            1981          21             155          0.32          228         10.9
                            1982          31             306          0.31          440         14.2
                            1983          49             405          0.31          587         12.0

                                                                  22

                               125                                                           75
                                                         Pink                                                      Sockeye
                               100 -
                               75                                                            50 -

                               50
                                                                                             25

                               25

                                                                                                    .. ...... .
                                                                                                 I   ..            i:'.; i:.:
                                0                                                             0                     . I .
                                   71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87            71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87

                               20                                                           20
                                                         Coho                                                        Chum

                               15  -                                                         15  -

                               10                                                            10
                                                                   -7
                                                                                                              AA
                                5
                                                                                             5

                                                                                                              .........
                                0
                                   71 72 73 74 75 76 77 7e 79 eO 81 82 83 84 85 86 87            71 72 73 74 75 76 77 70 79 810 8182 83 84 65 a6 67
                                6                                                                                     Year
                                                        Chinook
                                5  -

                                4

                                3                                                                Northern
                                                                                                 Southern
                                2

                                0
                                   71 72 73 74 75 76 77 78 79 So 81 82 83 84 86 86 87
                                                         Year
                                          .............

                                   Figure 1. Annual catches of North American salmon by region, 1971-1987.

                                                                                  23

                              Columbia fall stocks                     Columbia spring stocks
                    500                                       500
                                 McNary                             --0- Upper River
                    4oo          Lower hatchery               400          Lower River
                0

                    300                                       300

                    200 -                                     200

                    100                                       100

                       01                                 1      01
                       10       75      80      85       90      70      75        80     85       90

                             Sacr amento-San Joaquin                      Nushagak springs
                    900                                       500

                    800 -
                    700                                       400 -

                    600 -
                                                              300 -
                    500 -

                    400
                                                              200 -
                    300 -
                    200                                       100
                    100 -

                       0                                         0
                       70       75      80      85       90      70      75        80     85       90

                                       Yeer                                     Year

                  Figure2. Annual runs of chinook salmon for six North American stock complexes, 1971-
                           1987.

                                                        24

                                     Mushagak               500      McNary
                             500         1
                                     0 77                          0 83

                                                                 o 82
                             400-     0 75                  400

                                                                       84
                             300        0 76                300-
                                   0                        200-0
                             200 - 0     0
                                   0

                                    0
                                                                  0
                             100-  09       0               100  0
                                                                 0

                               0                              0
                               0        100      200          0        100      200
                                    Escapement                     Escapement

             Figure 3. Escapement-return relationships for Nushagak spring chinook salmon and upriver
                       Columbia fall chinooks (McNary). Curve fitted to 1966-1977 brood year returns
                       for the Nushagak with 1978-1981 returns shown by solid points. Curve fitted to
                       1966-1983 inriver returns to McNary (escapement age 3+, return includes all ages).
                       The 1984 brood year returns for ages 2 and 3 only.
                                    09
                                   0
                                                                 0

                                                      25

                                   y 111-.69 +16.603x R'2 0.900                  Y  132.20+ 66.507x R^2 - 0.788
                       500                                              500

                       400                                              400

                       300                                              300

                       200
                                                                        200

                       100                                              100

                          0                                 6.            00
                          0        5      10       is      20     25                       2       3       4       5

                                Y - 3.9371 + 0.39395x P^2 0.666                  Y-4.2074+ 1.7777x R^2 - 0.740
                         15                                             15

                         10
                                                                        10

                          5

                          0                                               0        i
                          0        5      10       15      20     25      0        1      2       3       4        5
                                  Smolts released (millions)                    Smolts transported (millions)

                       Figure 4. Inriver return and return per escapement regressed on numbers of hatchery smolts
                                   released and numbers collected at McNary and transported downstream, 1972-
                                   1983 brood years.

                                                                 26

                                   Hanford of McNary                              y - 25.761 0.21759x P-2  0,735
                     100                                .......           60
                                                                                D
                                                                          50            9
                     80
                                                                          40
                 00

                     60                                                   30          so
                 6                                                              90
                 is                                                                0
                 L                                                    6   20         @10
                     40                                 Adults        6
                                                                      1   10 -
                                                  0     Jacks
                     20  .........                 I I., . . I -           0      Cbe
                      60      65    70     75     80     85     90          0                   100                 200

                                   Verni.ta of Hanford                           y - 18.489 8.6485e-2x P^2  0.862
                     80                                                   60
                                                                                C

                                                                      0
                                                                          50
                     60
                                                                          40

                               XI                                         30
                     40      -%j 'U
                 6
                 0
                                                                          20
                     20
                                                                      06  10     (RV
                      01 .......                     .........        3110. 0 1    (h                             ---T
                      60      65    70     75     80     85     90          0                   100                 200
                                         Year                                      McNary adults     I 000s)

                      Figure 5.   Hanford Reach chinook salmon spawner distribution: (A) percent of McNary
                                  escapement estimated to be in the Hanford Reach, 1964- 1987; (B) percent of the
                                  number of aerially surveyed redds in Hanford Reach that were counted on Vemita
                                  Bar, 1964-1987; (C) number of redds, on Vemita Bar regressed on number of
                                  adults past McNary, 1981-1987 with observations from earlier years (open
                                  circles); (D) number of redds counted in Hanford Reach other than on Vemita Bar
                                  regressed on number of adults past McNary, 1981-1987 with observations from
                                  earlier years (open circles).
                                                                                 0 @40

                                                                27

                                            .1962-03                             1975-63
                                  500                                   600      0     1

                                  400                                   Soo

                                                                        400

                                  300

                              6                                         300
                                                                    6
                                                                    a
                                  200                               40

                                                                        200
                                          0
                                  100 -                                 100

                                     0                                     0
                                      0        100        200              0          100       200
                                           Escapement                          Escapement

                       Figure 6. Escapement-retum relationships for McNary fall chinook salmon (excluding jacks);
                                  inriver returns (left) and total returns, including ocean catches (right).

                                                                   28

                    DOE BP 3@1",@,

                    3c

                                                                                                                                                                                                           M

                                                                                              3 6668 00002 5553