Information On: Alaska Troll Fishery (Model Fishery #1)
........... S.E. Alaska Troll (excluding hatchery add-ON)... 1 , 1st Fishery Number 338000 , 1979, catch 300000 , 1980, catch 248000 , 1981, catch 242000 , 1982, catch 271000 , 1983, catch 236000 , 1984, catch 212827 , 1985, catch 229980 , 1986, catch 230901 , 1987, catch 216427 , 1988, catch 220966 , 1989, catch 263340 , 1990, catch 230712 , 1991, catch 162995 , 1992, catch 211590 , 1993, catch 176059 , 1994, catch 400000 , 1995, fp control 400000 , 1996, 400000 , 1997, 10 , Number of years to force ceilings 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994, Years to force ceilings
Information On: Northern BC Troll Fishery (Model Fishery #2)
........... Northern BC Troll ............................ 2 , 2nd Fishery Number 148726 , 1979, catch 163563 , 1980, catch 151731 , 1981, catch 174147 , 1982, catch 163055 , 1983, catch 179665 , 1984, catch 186723 , 1985, catch 152999 , 1986, catch 177457 , 1987, catch 152369 , 1988, catch 207679 , 1989, catch 154116 , 1990, catch 194015 , 1991, catch 142268 , 1992, catch 161719 , 1993, catch 165902 , 1994, catch prelim jan 26 95 400000 , 1995, through last year of clg mgt fp control 400000 , 1996, through last year of clg mgt fp cont 400000 , 1997, through last year of clg mgt fp control 10 , Number of years to force ceilings 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994, Years to force ceilings
Information On: Central BC Troll Fishery (Model Fishery #3)
[No information available at this time.]
Information On: West Coast Vancouver Island Troll Fishery (Model Fishery #4)
[No information available at this time.]
Information On: Washingto/Oregon Troll Fishery (Model Fishery #5)
[No information available at this time.]
Information On: Georgia Strati Troll Fishery (Model Fishery #6)
[No information available at this time.]
Information On: Alaska Net Fishery (Model Fishery #7)
[No information available at this time.]
Information On: Northern BC Net Fishery (Model Fishery #8)
[No information available at this time.]
Information On: Central BC Net Fishery (Model Fishery #9)
[No information available at this time.]
Information On: West Coast Vancouver Island Net Fishery (Model Fishery #10)
[No information available at this time.]
Information On: Juan de Fuca Strait Net Fishery (Model Fishery #11)
[No information available at this time.]
Information On: Puget Sound North Net Fishery (Model Fishery #12)
[No information available at this time.]
Information On: Puget Sound South Net Fishery (Model Fishery #13)
[No information available at this time.]
Information On: Washington Coast Net Fishery (Model Fishery #14)
[No information available at this time.]
Information On: Columbia River Net Fishery (Model Fishery #15)
[No information available at this time.]
Information On: Johnstone Strait Net Fishery (Model Fishery #16)
[No information available at this time.]
Information On: Fraser River Net Fishery (Model Fishery #17)
[No information available at this time.]
Information On: Alaska Sport Fishery (Model Fishery #18)
[No information available at this time.]
Information On: North/Central BC Sport Fishery (Model Fishery #19)
[No information available at this time.]
Information On: West Coast Vancouver Island Sport Fishery (Model Fishery #20)
[No information available at this time.]
Information On: Washington Ocean Sport Fishery (Model Fishery #21)
[No information available at this time.]
Information On: Puget Sound North Sport Fishery (Model Fishery #22)
[No information available at this time.]
Information On: Puget Sound South Sport Fishery (Model Fishery #23)
[No information available at this time.]
Information On: Georgia Strait Sport Fishery (Model Fishery #24)
[No information available at this time.]
Information On: Columbia River Sport Fishery (Model Fishery #25)
[No information available at this time.]
Information On: Alaska South SE Stock (Model Stock #1)
[No information available at this time.]
Information On: North/Central BC Stock (Model Stock #2)
Source: Chinook Technical Committee. 1988/89.
The North/Central stock group represents all BC stocks north of Vancouver Island. The major rivers represented in this group consist of the Skeena, the Nass, the Atnarko and the Kitimat Rivers. This stock is primarily made up of spring and summer run fish, although some fall or late summer runs are known to occur in the central coast (south of the Skeena). These stocks appear to largely stream-type (one year fresh water residence) and late maturing (predominant ages at return are ocean age 3 and 4). Ocean-type fish are more common in the central coast than in the north coast. The size of this stock is not certain. Visual Fishery Officer estimates sum to about 50,000 pieces during the 79-82 base period, but this is likely an underestimate. Currently, this stock is undergoing an increase and visual estimates approximate 100,000 pieces. Large enhancement projects have been mainly limited to the Bella Coola and Kitimat drainages. Both these facilities have egg capacities in the range of 3 to 5 million eggs and have not achieved full returns as yet.
Tag recoveries indicate that the distribution of ocean catch is mainly in the North BC and Alaskan troll fisheries, with important catches in the North/Central BC net and sport fisheries. These latter catches are divided between captures of out-migrating juveniles and in-migrating adults. The basic management goals for this stock grouping are to increase fisheries on surplus wild and hatchery fish for native and sport harvest.
Three brood years of tag codes have been summarized to provide the background harvest information for this stock grouping. The tag codes come from the Bella Coola and Kitimat hatcheries as follows:
BY 76 022016 Kitimat
022017 Kitimat
022018 Kitimat
BY 77 022020 Kitimat
022021 Kitimat
022022 Kitimat
022048 Bella Coola
BY 78 021614 Bella Coola
021732 Kitimat
The brood years selected were chosen to fully cover the base period in the model and these tag codes are the only ones available for these brood years. Because these codes come from the central coast only, only one stock group can be formed. There are no useable tag codes from the Skeena or the Nass to make a separate Skeena/Nass stock. The major problem with all these codes is the lack of any escapement data. In order to estimate escapements for this stock, the maturity schedule from the upper Georgia Strait stock was used (this is the oldest stock among the input groups).
Information On: Fraser River Early Stock (Model Stock #3)
Source: Chinook Technical Committee. 1988/89.
The Fraser River divides naturally into three large groupings. These are the Fraser River above Hope, the Thompson River drainage (the largest tributary) and the Harrison (Late) component. Almost all stocks returning above Hope enter the lower river before September, with a major peak occuring in late June or early July. It is hypothesized that this peak corresponds with the large runds returning to uppermost areas above Prince George (these include the Nechako, the Bowron, Slim Creek, and Tete-Jaune). However, there is considerable migration into the river by chinook throughout the summer. Stocks which return later (but are still considered summer runs) include the Chilko, the Quesnel, and most of the runs returning to the Thompson drainage. Fresh-water life history scale patterns indicate taht most upper Fraser stocks appear to be yearling salt-water migrants. They are also an older stock with the primary ages at return being ocean age 3 and 4. However, stocks which spawn in the Thompson drainage are mixed, with the far-north migrating Shuswap stock migrating to the ocean during the first summer and returning predominantly as ocean age 3 fish. Stocks which spawn in the interior dry-belt (e.g., Nicola River) migrate as yearlings and return as ocean age 2 fish.
Escapement stock size estimates are visual estimates made by field personnel during peak spawning periods. They are likely to be underestimates (as is usual with these types of estimates). Tables 7 to 10 in the 1985 CTC Agency Report summarize the visual estimates to the various sub-groupings. The average count for the entire run above Hope during the 79-82 base period is 43,000. The current estimate is in the order of X0,000 to X0,000. There are major enhancement facilities ont he Quesnel River (about 3 million eggs) and on the Eagle River (South Thompson drainage / 2 million eggs). Other facilities are scattered, are smaller, and are mainly in the Thompson drainage basin. The total hatchery production capacity in the upper Fraser is X,000,000 eggs.
Wild tagging was attempted in the upper Fraser for 3 to 4 years in succession. Tag recoveries have been almost uniformly poor. Tags applied on the Chilko and Tete-Jaune stocks have had survival to recovery values of less than 0.1% and more than half of the survival has been escapement (expansion of Petersen mark/recovery estimates). The few fishery recoveries have been scattered between the Georgia Strait sport, an occasional northern troll recovery, and the Fraser terminal gillnet fishery. Tagging in the Thompson drainage has been relatively more successful and recovery rates int he ocean fisheries have been about 0.3%. The recoveries indicate that these fish are true far-north migrating stocks being caught predominantly in the North BC and Alaska troll fisheries. They also show up in all the approach net fisheries (including Puget Sound) and have relatively few contributions to the Georgia Strait fisheries. The stated escapement goal for this stock is 96,000 (Table 4, 1985 CTC Agency Report). Management goals for this stock include establishing directed in-river sport fisheries on identified surplus fish. These stocks are also harvested by native fisheries (which may partially explain the lack of tag recoveries for the Chilko and Tete-Jaune stocks).
There are at least 16 codes ranging from the 75 to the 79 brood years which were applied to wild Fraser stocks. Of these, the following 6 codes were used:
BY 78 021602 Chilko
021658 Chilko
021625 Shuswap
021638 Shuswap
BY 79 021601 Shuswap
021755 Shuswap
These codes were selected entirely on the basis of actual contribution numbers. Other codes supplied so few recoveries (either because not enough were marked or the survival was poor) that their use would not affect the estimated harvest rates. Again, there were insufficient data to distinguish between the Thompson drainage stock and the upper Fraser stock. Escapement data were collected from both the above spawning stocks in 1983 and 1984. Therefore, there are estimates of age 4 and age 5 spawners only. The age 5 estimates were allowed to stand (as these have to be assumed in the calculation procedure). However, the age 4 estimate for the 1979 brood year Shuswap appeared to be extremely low. Therefore, the same calculation method as used for the North BC stock was used to estimate all other escapements.
Information On: Fraser River Late Stock (Model Stock #4)
Source: Chinook Technical Committee. 1988/89.
It has long been known that there is a distinct fall run of chinook to the Fraser. It peaks in the lower river in the last week of September and the fish all have a white flesh colour. The latter characteristic is traceable in the commercial sale information from the terminal gillnet fishery as white-fleshed chinook are sold at a different price and are kept separate on the fish tickets. In the past, this stock has supported substantial directed large-mesh gillnet fisheries, with catches of 10,000 to 20,000 recorded in single 12-hour openings.
This stock appears to be concentrated entirely in the short section of the Harrison River between harrison Lake and the confluence with the Fraser River (about 20 kilometers). It is unknown if fish migrate past this section into upper reaches of the drainage. This stock is entirely ocean-type and appears to be a relatively early maturing stock with a large proportion of age 3 (ocean age 2) fish. Juvenile fish do not appear to rear at all in the spawning stream. Instead, fry migration studies record substantial chinook fry migrations in the lower Fraser River (these usually peak in mid-April). The fry all appear to be recently emerged. The hypothesized life history for this stock assumes that it invades available habitat throughout the lower Fraser, in particular the tidal marshes of the estuary, where they have been shown to reside up to six weeks. Visual counts of the spawning stock by Fishery Officers have ranged from estimates of less than 10,000 in the mid-60's to mid-70's to 20,000 to 40,000 in the 80's. Petersen mark/recovery estimates made since 1984 indicate that the spawning stock may range up to 150,000. Estimates of total fry migration in the mid-7o's seemed to indicate at that time that the spawning stock could be 5 to 10 times larger than the Fishery Officer estimate in order to account for the size of the fry migration. The stated escapement goal is 175,000 as measured with a Petersen estimate (Table 4 of the 1985 CTC Agency Report). Management goals include the establishment of a terminal sport fishery directed at the large jack population of this stock and to surplus fish when available.
Enhancement on this stock has occurred on the Chehalis River (a tributary of the Harrison) and on the Chilliwack River (on the south side of the Fraser). The Chehalis has an egg target of 1,000,000 chinook eggs and the Chilliwack takes about 3,000,000 chinook eggs. However, the Chehalis hatchery has had very poor survivals of chinook within the hatchery (less than 40%) due to an endemic disease problem. The Chilliwack hatchery is trying to establish red-fleshed summer runs into that river (the native run thas disappeared) and expects to gradually phase out the rearing of white-fleshed chinook.
This stock was the first stock tagged with coded wire tags in the 1971 brood years. However, this tag data cannot be used because the recovery program was not in full development at the time the tags returned. Tagging did not resume on this stock until the 1981 brood year, when experimental hatchery releases were made from the Chehalis and the Chilliwack hatcheries. Ocean tag returns from these releases indicate that this stock contributes substantially to all fisheries inside Georgia Strait (40% of the recoveries), to the west coast of Vancouver Island (30% of the recoveries), and to the approach net fisheries (including Puget Sound net 15% of the recoveries). The tag codes used are:
BY 81 022163 Chilliwack
022205 Chehalis
No escapement data are available for either of these stocks. When the maturity schedules for fall-run Georgia Strait stocks (Big Qualicum) were used to estimate the escapement, a total harvest rate of nearly 90% was calculated. This was because of the large (terminal) net harvest rate on the lower Fraser stock when compared to the Georgia Strait stock. However, the maturity schedule used was arbitrarily chosen such that the resultant total harvest rate would be near 80%. See Appendix for details of the calculations. In order to scale the base period escapement to the stated optimum (which is based on the Petersen estimates), the visual estimates were multiplied by 6, which the average of the ratio of the Petersen estimates to the visual estimates over the period 1982 to 1985 (earlier multiplications are based on expansions of intensive dead pitch activities).
Information On: West Coast Vancouver Island Hatchery Stock (Model Stock #5)
Source: Chinook Technical Committee. 1988/89.
There is a considerable hatchery stock associated with the west coast Vancouver Island stock grouping. Approximately 9M fingerlings are released annually from the Robertson Creek hatchery on the Somass River. Another 1.5M fingerlings are released by the Nitinat hatchery and it is expected that the Conuma hatchery in Tahsis Inlet will release another 1.5M fingerlings. Calculation of the optimum and the productivity parameters for this stock is given in the productivity section of the documentation. The same tag codes were used to calculate the harvest rates as for the naturally spawning stocks.
Information On: West Coast Vancouver Island Natural Stock (Model Stock #6)
Source: Chinook Technical Committee. 1988/89.
This stock grouping represents all stocks which spawn on the west coast of Vancouver Island. Although this group of stocks is dominated by the Somass River stock (Barkley Sound), there are other stocks of importance in the Nitinat River, the Kennedy River, the Gold River, and the Marble River. As in most area of BC, escapement estimates are obtained through visual counts by field personnel. These counts are not obtained through any established or rigorous methodology and probably constitute an underestimate of stock size. The escapement is complicated by the presence of the Robertson Creek hatchery. The base period naturally spawning escapement is estimated to be about 7500 pieces by visual estimate. Recent (1984-1986) work using various mark/recapture estimation procedures place the natural spawning stock in the 40,000 to 70,000 range. The escapement objective for this stock is stated at 91,000. This includes an objective of 70,000 for the naturally spawning portion of the Somas, which is based on the stock sizes seen by the 1984 Petersen estimate.
All biological information from this area indicate that this stock is a fall run stock with ocean ages 2 and 3 predominating. Almost all juvenile migration occurs in the spring and early summer (sub-yearling). This stock is a far-north migrating stock based on the distribution of fishery tag recoveries which show that 60% occur in the North BC and Alaska troll fisheries. Another 11% of the recoveries occur in the west coast Vancouver Island troll fishery, and outside net recoveries account for another 7%. There are substantial terminal net and sport fisheries which account for 17% of the input data recoveries.
The CWT codes used to construct the input stock data all come from Robertson Creek hatchery codes. The same codes used in the 1984 version of the model were used in the 86/87 version. The codes used were:
BY 74 020606
020609
BY 75 020408
020409
BY 76 021630
021631
BY 77 022217
022218
The codes used are the production codes associated with each brood year. More brood years were used for this stock than in other input stocks because some changes occurred in the collection of rack information after 1981. Accordingly, it was feared that using the more recent brood years would bias the estimates of harvest rates. However, data from the older brood years were not considered to be as representatiive of the harvest patterns to be simulated by the PSC model. Therefore, all the brood years used were averaged as a compromise.
In order to calculate a base period escapement for this stock that would be in the same ratio as the stated optimum, the visual estimates for the naturally spawning fraction of the Somass River were increased by a factor of 5. This factor is approximately the ratio of the 1984 Petersen estimate to the 1984 visual observation estimate.
Information On: Upper Georgia Strait Stock (Model Stock #7)
Source: Chinook Technical Committee. 1988/89.
Georgia Strait consists of at least two distinct groups of stocks. These two groups are the rivers flowing into the Strait of Georgia along the east coast of Vancouver Island and the rivers flowing into the mainland inlets on the other side of the Straits. The rivers flowing into Johnstone Strait (both east and west sides) form a third grouping of stocks which is allied with the Georgia Strait stocks. The 1984 version of the PSC model lumped all three of these stock groupings into a single stock for modeling purposes. The 1986/87 version has divided the Johnstone Strait grouping away from the Georgia Strait stock groups, largely on the basis of tag recoveries from the Quinsam hatchery.
The upper Georgia Strait stock group represents all rivers flowing into the top of Georgia Strait including the upper mainland inlets (Puntledge River, Campbell/Quinsam River, Bute River, and Southgate River), Johnstone Strait (Klinaklini River, Nimpkish River), and Queen Charlotte Strait (Kingcome River, Keough River). This is a diverse group of stocks for which little biological data are available. It is suspected that the majority of stocks which spawn in the large, cold, and poorly productive streams of the mainland inlets are yearling migrants which have a far-north migration pattern. They are slo primarily spring and summer run fish. The primary age at return would be ocean age 3 and 4. Stocks returning to Vancouver Island streams are mainly fall and late summer run and appear to be summer or late spring (fingerling) migrants, but they also have the far-north migration pattern and appear to be mainly ocean age 3 and 4 at maturity, with a significant component of ocean age 5 as well. Stock abundance estimates are extremely unreliable due to the remoteness of many of the large rivers and to the quantity of glacial till which colour the river waters. Visual estimates are also difficult to time so that peak spawning periods are covered. The total estimated spawning stock averaged 11,500 pieces during the base period and the stated escapement goal is 23,000 (Table 4 of the 1985 CTC Agency Report does not sub-divide the total Georgia Strait goal). These numbers include river spawning in the Quinsam, Campbell and Puntledge Rivers. There are no specific management goals for this stock grouping apart from maintaining current fishing levels in local areas. Enhancement in this stock group is centered about the Quinsam hatchery with an egg target of 2,000,000 eggs. Total production capacity of all facilities is X,000,000 eggs.
Tag returns from the Quinsam hatchery establish the far-north migration pattern for this stock and the older average age of maturation. The majority of the fishery recoveries for this stock come from the North BC and Alaska troll fisheries (45% of the recoveries) and from the net fisheries of Johnstone Strait, North BC and Alaska (40% of the recoveries). The balance of the recoveries come from miscellaneous fisheries, particularly the sport fisheries of North BC considerable sport fishery which develops around the estuary of the Campbell River in the fall.
The tag codes used in the 1986/87 version of the model are the same as used in the 1984 version. The following codes were used:
BY 77 021736 Quinsam
021737 Quinsam
021738 Quinsam
BY 78 021759 Quinsam
These codes are the production codes associated with this hatchery during those two brood years. Escapement data are routinely collected at this hatchery, including some (unknown) fraction of strays below the hatchery in both the Quinsam and Campbell Rivers. Escapement below the hatchery was doubled to account for the estimated coverage during the recovery effort. This expansion factor is the average of the river coverage fraction estimated from mark/recovery work from 1984 to 1986.
The visual escapement data for 1986 in the mainland inlet area of upper Georgia Strait (Area 13) was also adjusted for the purposes of modeling input. This was done because it appeared that the field staff had made an extremely large count of spawners in the main river of this area (Southgate River) primarily due to the coincidence of very clear observation conditions, good weather, and peak spawning period. All other counts in the other areas of this stock grouping showed declines or modest increases. Therefore the average relative change from 1985 to 1986 for all other systems in the upper Georgia Strait stock group was used to adjust the 1985 visual estimate for Area 13.
Information On: Lower Georgia Strait Natural Stock (Model Stock #8)
Source: Chinook Technical Committee. 1988/89.
The rivers covered by this stock grouping include all rivers flowing into Georgia Strait from a point about midway down the east coast of Vancouver Island (Big and Little Qualicum Rivers, Nanaimo River, Chemainus River, and Cowichan River). It also includes the lower inlets on the east side of Georgia Strait (Toba River, Jervis River, and Squamish River). These rivers were lumped with the upper Georgia Strait stock in the 1984 version of the PSC model. In order to calculate base period escapements and escapement goals, the hatchery production had to be separated from the naturally occurring spawning. For the Lower Georgia Strait stock grouping, all river escapements were including in the naturally spawning fraction. Rack returns for the Big Qualicum and Capilano only were included in the hatchery escapements. The base period escapement for this stock was 17,000 and the stated escapement goal is 33,000. Management goals are as for the upper Georgia Strait stock (see above).
The Vancouver Island streams from this stock appear to be late fall run stocks with a limited northward migration pattern. A significant proportion of these fish appear to reside throughout their marine life in Georgia Strait itself. The majority of the fish appear to migrate to sea after less than 3 months of freshwater rearing. Age at maturity appears to be divided between ocean age 2 and age 3 with ocean age 4 almost non-existent. The mainland inlet stocks are less well-known with respect to life history patterns. The Squamish River used to have yearling migrants and an early fall run timing. However, this stock has been badly overfished, and current timing from hatchery returns indicate that a later fall run pattern currently predominates. In addition, current data indicate that the Squamish has fingerling sea-ward migrants. Information from the other inlet rivers are not available.
Tag returns from Big Qualicum and Capilano hatcheries indicate that 70% of the fishery recoveries from this stock occur in Georgia Strait. Only 99% of the recoveries occur in the northern troll fisheries. Most of the other recoveries occur in net fisheries, particularly in Johnstone Strait (8%) and the central area (7%).
The tag codes used in the 1986/87 version of the model are the same as used in the 1984 version. The following codes were used:
BY 77 021639 Capilano
021642 Capilano
021726 Big Qualicum
021727 Big Qualicum
BY 78 021612 Big Qualicum
021613 Big Qualicum
021656 Big Qualicum
021728 Capilano
021729 Capilano
021730 Capilano
These codes are the production codes associated with these hatcheries during the two brood years. A fence is maintained at the mouth of the Big Qualicum River and all tags are recovered at passage through the fence. There was some uncertainty associated with the escapement recoveries from the Capilano hatchery. Therefore, the escapement returns from this hatchery were not used in the model input. Instead, the annual harvest rate of the Big Qualicum was calculated and applied to the combined catch data from both hatcheries.
Information On: Georgia Strait Hatchery Stock (Model Stock #9)
Source: Chinook Technical Committee. 1988/89.
The hatchery production of Georgia Strait was included as a separate stock in the 86/87 version of the PSC model. Hatchery rack returns from Quinsam, Puntledge, Big Qualicum and Capilano were averaged over the 79-82 base period to calculate the base period escapement. The escapement goal calculations and productivity parameter calculations are shown in productivity section of the documentation. The same tag codes as used for the naturally spawning lower Georgia Strait stock were used to calculate the harvest rates for this stock. Current releases for all hatcheries in Georgia Strait total about 19M fingerlings with an expected maximum under current plans of 20M.
Information On: Nooksack/Samish Fingerling Fall Stock (Model Stock #10)
Source: Chinook Technical Committee. 1988/89.
The Nooksack/Samish region is managed for hatchery production during the return period of fall chinook. The stock included in the model represents both natural and hatchery production since it is believed that the majority of the natural production originates from hatchery strays. The average run size and escapement during the base period is given below.
The average escapement includes an estimated 218 fish which originated from yearling production. Hence, the stock was calibrated to an escapement of 11,923 fish. The escapement goal is the average escapement in 1979-82 minus the estimated average escapement of 218 fish which originated from yearling production (estimate obtained from the WDF/NBS model).
GENERAL COMMENTS ON PUGET SOUND/WASHINGTON COASTAL STOCKS
Information On: Puget Sound Hatchery Fingerlings Stock (Model Stock #11)
Source: Chinook Technical Committee. 1988/89.
The Puget Sound fall hatchery fingerling is an aggregate stock which includes a South Puget Sound and a Hood Canal component. Each of these areas is managed for hatchery production with the exception of the Green River stock in South Puget Sound. Natural production in these areas is grouped in a separate stock aggregate, the Puget Sound fall natural stock. Average run sizes and escapement goals for components of the Puget Sound hatchery stock are listed below.
Escpmnt Avg. Escpmnt
Production Unit Goal 1979-81
Hood Canal 2,459 2,018
South Puget South 20,197 27,549
Total 22,656 29,567
The stock was scaled to an escapement of 24,055 since the average escapement includes an estimated 5,512 fish (Hood Canal = 292; SPS = 5,220) which originated from yearling production (estimated from cohort analysis of yearling stocks).
Input data were developed independently for the Hood Canal and South Puget South stocks before each stock
South Puget South. Tag codes from brood years 1978 and 1979 were used for the South Puget South component.
Brood Year 1978 1979
Catch 2,720 4,170
Brood Weight 1.5331 1.0000
Tag Codes 631814 050722
621842 631903
631907 631943
631935 631944
631936 632020
631940 632063
631945 632103
632104
The escapement for the tag codes was estimated using the average terminal catch/escapement ratio.
Year Catch Escpmnt Ratio
1979 14,614 29,785 0.4906
1980 20,628 27,200 0.7584
1981 23,858 25,663 0.9297
1982 14,696 19,021 0.7726
Average 0.7378
Average PS Net Expected CWT Escpmnt
Catch/Escpmnt CWT Rec. Escpmnt Escpmnt Scale
0.7378 1,969 2,669 973 2.7428
Hood Canal. The distribution of the Hood Canal stock component was modelled using tag codes from brood years 1978 and 1979.
Brood Year 1978 1979
Catch 1,419 433
Brood weight 1.0000 3.2771
631752 632041
632915 632109
The escapement for the Hood Canal tag groups was estimated from the average terminal catch/ escapement ratio.
Year Catch Escpmnt Ratio
1979 2,151 1,264 1.7017
1980 4,591 1,836 2.5005
1981 8,380 2,954 2.8368
1982 3,479 4,949 0.7030
Average 1.9355
Average PS Net Expected CWT Escpmnt
Catch/Escpmnt CWT Rec. Escpmnt Escpmnt Scale
1.9355 830 429 310 1.2833
Aggregation of Components. The South Puget Sound and Hood Canal components were weighted prior to aggregation to preserve the relative abundance of each component. Escapement is the average from 1979 through 1982 minus the estimated escapement from yearling production.
Escapement
Stock CWT Observed Scale
South Puget Sound 2,669 20,197 .757
Hood Canal 429 2,459 .573
The scale factor (or expansion factor) is equal to the observed escapement divided by 10 times the CWT escapement.
GENERAL COMMENTS ON PUGET SOUND/WASHINGTON COASTAL STOCKS
Information On: Puget Sound Natural Fingerling Stocks (Model Stock #12)
Source: Chinook Technical Committee. 1988/89.
The Puget Sound natural stock includes natural stocks returning to South Puget Sound and Hood Canal. Average escapements and the escapement goal for each component are listed below.
Escpmnt Avg. Escpmnt
Production Unit Goal 1979-81 1975-78
Hood Canal 1,112 1,867
South Puget Sound 14,935 9,914
Total 14,145 16,047 11,781
The escapement goal is the average escapement from 1979 though 1982. The prior escapement was inadvertently computed using the years 1975 through 1978 rather than 1976 through 1979.
The same tag codes were used to represent the natural stocks as were used for the Puget Sound hatchery stocks, but the escapement was estimated using the terminal catch/escapement ratio for natural stocks rather than hatchery stocks.
Hood Canal Natural
Year Catch Escpmnt Ratio
1979 2,960 2,202 1.3442
1980 1,561 843 1.8517
1981 2,268 292 7.7671
1982 2,470 437 5.6522
Average 4.1538
South Puget Sound Natural
Year Catch Escpmnt Ratio
1979 8,006 17,011 0.4706
1980 8,506 19,467 0.4369
1981 4,557 8,326 0.5473
1982 6,581 8,002 0.8224
Average 0.5693
Average PS Net Expected CWT Escpmnt
Stock Catch/Escpmnt CWT Rec. Escpmnt Escpmnt Scale
HC 4.1538 830 200 310 0.6446
SPS 0.5693 1,969 3,459 973 3.5546
The South Puget Sound and Hood Canal components were weighted prior to aggregation to preserve the relative abundance of each component.
Escapement
Stock CWT Observed Scale
South Puget Sound 3,459 13,202 3.82
Hood Canal 200 944 4.72
The observed escapement is the average from 1979 through 1982. The scale factor (or expansion factor) is equal to the observed escapement divided by the CWT escapement.
GENERAL COMMENTS ON PUGET SOUND/WASHINGTON COASTAL STOCKS
Information On: Puget Sound Hatchery Yearling Stock (Model Stock #13)
Source: Chinook Technical Committee. 1988/89.
The Puget Sound yearling stock consists of hatchery production of yearlings from hatcheries in South Puget Sound (including accelerated production from the University of Washington), Hood Canal, Skagit, and the North Puget Sound region. Average escapements and the escapement goal for each component is given below.
Escpmnt Avg. Escpmnt
Production Unit Goal 1979-81
Hood Canal 292 292
South Puget Sound 5,220 5,220
North Puget Sound 5,320 5,320
Total 10,832 10,830
The escapement goal is equal to the escapement estimated from cohort analysis.
The expansion of the tag group to represent stocks was done slightly differently for the yearling stocks than for other stocks in Puget Sound. This modification was necessary because of the lack of data on the abundance of the yearling stocks relative to fingerling stocks. Fish originating from fingerling or yearling production are not differentiated in the hatchery escapement records.
In order to estimate the total abundance of yearling stocks, the recoveries of marked fish were multiplied by an expansion factor related to the average marked to unmarked ratio. The expansion factor was calculated by:
Fi = N / (Mi * n)
South Puget Sound. The South Puget Sound stock consisted of accelerated production from the University of Washington and the production of yearlings from other hatcheries in South Puget Sound. Tag codes and data used to compute the expansion factors are given in the tables below.
University of Washington Accelerated Production Mean Release (1976-79): 159,115
Brood Year 1977 1978 1979
Code Marked Code Marked Code Marked
111601 26,185 111603 24,639 111627 18,488
111602 26,331 111604 23,653 111628 20,573
111605 27,165 111629 20,008
111606 23,978 111630 15,828
111617 3,339 111631 20,196
111618 53,537 111632 21,822
111624 3,637
Marked 52,516 159,048 116,915
Factor 1.0099 0.3335 0.4536
Other South Puget Sound Yearling Production Mean Release (1976-79): 1,534,698
Brood Year 1978 1979
Code Marked Code Marked
631853 3,665 632015 16,080
631905 20,400 632019 30,929
632004 48,196 632027 10,243
632023 13,495 632055 9,696
632056 8,651
632128 10,433
632220 4,659
632221 3,060
632228 10,169
Marked 85,756 103,920
Factor 8.9481 7.3840
Escapement was estimated using the average terminal catch/escapement ratio.
UW Accelerated (Lake Wash. hatchery entry in run reconstruction)
Year Catch Escpmnt Ratio
1979 1,003 6,115 0.1640
1980 995 6,541 0.1521
1981 1,358 6,109 0.2223
1982 2,806 7,219 0.3887
Average 0.2318
Other South Puget Sound (Total SPS hatchery entry in run reconstruction)
Year Catch Escpmnt Ratio
1979 14,614 29,785 0.4906
1980 20,628 27,200 0.7584
1981 23,858 25,663 0.9297
1982 14,696 19,021 0.7726
Average 0.7378
Average PS Net Expected CWT Escpmnt
Stock Catch/Escpmnt CWT Rec.Escpmnt Escpmnt Scale
UW 0.2318 532 2,295 285 8.0529
SPS 0.7378 2,159 2,926 453 6.4592
Weighting the UW and Other Sound stocks prior to aggregation was not necessary since the tag codes had already been expanded to account for the total production which they represented.
Hood Canal. Data used to construct the Hood Canal yearling stock is given in the table below.
Hood Canal Yearling Production Mean Release (1976-79): 316,459
Brood Year 1978 1979
Code Marked Code Marked
631637 6,732 632057 6,245
631840 1,098
631852 15,935
Marked 23,765 6,245
Factor 6.6581 25.3369
The average terminal catch/escapement ratio was used to estimate the escapement for the Hood Canal yearling stock.
Year Catch Escpmnt Ratio
1979 2,151 1,264 1.7017
1980 4,591 1,836 2.5005
1981 8,380 2,954 2.8368
1982 3,479 4,949 0.7030
Average 1.9355
Average PS Net Expected CWT Escpmnt
Stock Catch/Escpmnt CWT Rec. Escpmnt Escpmnt Scale
HC 1.9355 568 293 232 1.2629
North Puget Sound Yearling
The North Puget Sound yearling stock includes hatchery release from the Skagit and Snohomish production areas. One Skagit and one Skykomish tag code were used to represent the North Puget Sound yearling production.
North Puget Sound Yearling Production Mean Release (1976-79): 1,619,205
Brood Year 1976
Code Marked
631610 73,428
631701 98,972
Marked 172,400
Factor 9.3921
The expansion factor of 9.3921 produced a catch of over 9,999 fisheries which is more than permitted by the current format of the input data. In order to avoid this problem, the expansion factor was divided by 10. When the Puget Sound yearling aggregate was created, the South Puget Sound and Hood Canal components were multiplied by .1 to preserve the relative abundance of each stock.
The escapement for the North Puget Sound yearling stock was estimated from the terminal catch/escapement ratio.
(Total Skagit, Snohomish, and Tulalip hatchery run)
Year Catch Escpmnt Ratio
1979 2,695 2,160 1.2477
1980 7,545 5,083 1.4844
1981 8,633 4,638 1.8614
1982 3,842 3,377 1.1377
Average 1.4328
Average PS Net Expected CWT Escpmnt
Catch/Escpmnt CWT Rec. Escpmnt Escpmnt Scale
1.4328 762 532 285 1.8667
Aggregation of Components. The Hood Canal, South Puget Sound, and North Puget Sound stocks were aggregated into a single stock Puget Sound yearling stock. Since the North Puget Sound recoveries had been divided by 10, the Hood Canal and South Puget Sound stocks were given weight factors of .1 at the time of aggregation.
GENERAL COMMENTS ON PUGET SOUND/WASHINGTON COASTAL STOCKS
Information On: Nooksack Spring Stock (Model Stock #14)
Source: Chinook Technical Committee. 1988/89.
Limited information is available for the Nooksack spring stock, but it appears that escapement has been less than optimum. The available data on the stock is summarized below. The estimated terminal run sizes, escapement, and escapement goal are under review by a tribal/state committee.
Since escapement estimates were not available for years prior to 1980, the input data was scaled to the average escapement in 1980-81. The escapement in the prior cycle was estimated from a regression of escapement versus time (intercept = 261,862; slope = -131.559). The input data incorrectly had the prior escapement reported as 507.
Code 051418 from brood year 1981 was used to represent the stock. Since this was outside of the base period of the model, COHSHAK4 was used to modify the recoveries to account for changes in fishing mortality.
GENERAL COMMENTS ON PUGET SOUND/WASHINGTON COASTAL STOCKS
Information On: Skagit Summer Fall (Model Stock #15)
Source: Chinook Technical Committee. 1988/89.
Summer chinook in the Skagit are managed on a natural basis although a small hatchery component exists. The escapement goal and average escapement are provided below.
Escpmnt Avg. Escpmnt
Production Unit Goal 1979-81 1976-79
Skagit Summer 14,900 14,207 12,185
Tag codes used to represent the stock were obtained primarily from wild stock tagging conducted in 1977 and 1978. Recoveries from these tagging projects were limited. To provide additional recoveries, a hatchery tag group from the 1976 brood was included as well. The tag codes and the weight for each brood year are listed below:
Brood Year 1976 1977
Catch 1,925 491
Brood Weight 1.000 3.9206
631624 (natural) 631630 (natural)
631625 (natural) 631631 (natural)
631626 (natural) 631632 (natural)
631627 (natural) 631633 (natural)
631628 (natural) 631635 (natural)
631629 (natural) 631636 (natural)
631606 (hatchery)
Several methods were utilized to estimate the escapement for the Skagit tag codes.
Year Catch Escapement Ratio
1979 10,509 13,605 0.7724
1980 10,649 20,345 0.5234
1981 13,071 8,670 1.5076
1982 13,696 10,439 1.3120
Average 1.0289
Average PS Net Expected CWT Escpmnt
Catch/Escpmnt CWT Rec. Escpmnt Escpmnt Scale
1.0311 599 581 65 8.9385
The maturation schedule method relied upon maturation rates from the Puget Sound fingerling stock and an input harvest rate for age 5 fish. The age 5 harvest rate was selected so that the average escapement scale for the age 3 and 4 escapements was equal to the age 5 escapement scale.
Age 5 Harvest Rate = .6119
Age 4 Maturation Rate = .8468
Age 3 Maturation Rate = .1500
Age 2 Maturation Rate = .0141
The ocean harvest rate method utilized the equation:
R = O / (O + E + T)
or, solving for E
E = (O - R * (O + T)) / R
where O is the ocean catch, E is the age 3 through 5 escapement, T is the terminal catch, and R is the ocean harvest rate. The ocean harvest rate of the Puget Sound fingerling stock was on the assumption that it would be similar to that of the Skagit stock. The expected escapement for the Skagit is given by:
E = 3,217 - (.58) * (3,850) / .58 = 1,697
The first method resulted in a harvest rate (total harvest rate equal to .8634 without shakers) which appeared to be unrealistically high given the stability of the escapement for the stock. Method 2 gave a lower ocean harvest rate than the Puget Sound fingerling stock, which also seemed unreasonable. Method 3 was selected because it resulted in realistic ocean, terminal, and total harvest rates.
Results from the above CWT experiments show the principal fisheries harvesting these stocks outside Puget Sound are the West Coast Vancouver Island troll fishery and the Georgia Strait sport and troll fisheries.
GENERAL COMMENTS ON PUGET SOUND/WASHINGTON COASTAL STOCKS
Information On: Stillaguamish Wild Stock (Model Stock #16)
Source: Chinook Technical Committee. 1988/89.
The Stillaguamish stock is managed on a natural stock basis. The average escapement and escapement goal is given below:
Escpmnt Avg. Escpmnt
Production Unit Goal 1979-81 1976-79
Stillaguamish Summer 2,000 831 1,511
The Stillaguamish stock was tagged in brood years 1980 through 1982. The tag code use in each brood year is given below. Since no escapement data were available, the age composition of the Skagit stock was used for the Stillaguamish stock.
Brood Year 1980 1981 1982
Tag Code 05048 051063 051427
Since the tagging occurred outside of the model base period, the recoveries were adjusted using the procedure implemented in the COHSHAK4 program. This procedure requires that escapement data exist for each brood year. No escapement recoveries existed for any of the Stillaguamish tag codes. The terminal catch/escapement ratio was used to estimate the age 3 to 5 escapement for each tag code, and the age composition of the Skagit escapement was used to distribute the total escapement among age classes.
Average PS Net Expected
Code Catch/Escpmnt CWT Rec. Escpmnt by Age
2 3 4 5
050843 1.50 6 0.4 1.5 2.5 0.2
051063 1.10 6 0.5 2.0 3.4 0.3
051427 0.89 17 1.9 7.1 11.7 1.2
After COHSHAK4 had been used to convert the tag recoveries to the base period, the three methods previously discussed for the Skagit were used to estimate the Stillaguamish escapement.
The average terminal catch/escapement ratio from 1979 through 1982 was 2.72.
Year Catch Escpmnt Ratio
1979 1,485 1,042 1.4251
1980 1,968 821 2.3971
1981 2,400 630 3.0895
1982 2,513 773 3.2510
Average 2.7207
Data for the maturation method were identical to those used for the Skagit River with the exception of the age 5 harvest rate, which was fit using the technique previously described for the Skagit River.
Age 5 Harvest Rate = .8319
Age 4 Maturation Rate = .8468
Age 3 Maturation Rate = .1500
Age 2 Maturation Rate = .0141
For the ocean harvest rate method,
E = 492.3 - (.58) * (563) / .58 = 286
Methods 1 and 2 gave similar results with Method 2 resulting in a slightly higher total harvest rate. The escapement resulting from Method 1 was consistent with tag code data from other Puget Sound areas given the low contribution rates of the Stillaguamish tag codes. Use of Method 3 resulted in an escapement which seemed too large given the data from tag codes in other Puget Sound regions.
GENERAL COMMENTS ON PUGET SOUND/WASHINGTON COASTAL STOCKS
Information On: Snohomish Wild Stock (Model Stock #17)
Source: Chinook Technical Committee. 1988/89.
No tag code data were available to model the distribution of the Snohomish natural stock. Tag codes from the Stillaguamish stock were chosen to represent the Snohomish based on the geographical proximity of the stocks. The average escapement and escapement goal for the Snohomish stock are given below.
Escpmnt Avg. Escpmnt
Production Unit Goal 1979-81 1976-79
Snohomish Summer 5,250 5,244 5,824
The escapement for the Snohomish stock was estimated using the terminal catch/escapement ratio.
Year Catch Escpmnt Ratio
1979 7,674 5,903 1.3000
1980 11,130 6,460 1.7229
1981 6,397 3,368 1.8993
1982 4,724 4,379 1.0788
Average 1.5003
GENERAL COMMENTS ON PUGET SOUND/WASHINGTON COASTAL STOCKS
Information On: Washington Coastal Wild Stock (Model Stock #18)
[No infomation available at this time.]
Information On: Columbia River Upriver Brights Stock (Model Stock #19)
Source: Chinook Technical Committee. 1988/89.
The majority of the Columbia River Upriver Brights (URB) production originates from natural and hatchery production areas in the main stem of the Columbia River between McNary and Priest Rapids Dams. The URB adult return has averaged about 117,000 since 1970. the present spawning escapement goal is 40,000 adults measured at the McNary Dam adult counting facility.
Historically, most of the ocean harvest of URB fall chinook occurred in British Columbia and Alaska. URB chinook was selected as a harvest rate indicator based on it's significant contribution to Canadian and Alaskan fisheries. This stock also represents a major production unit of Columbia River chinook. In addition, the URB fall chinook was one of the four original indicator stocks used in the multi-stock model for the 1984 Pacific Salmon Treaty negotiations.
CWT Codes
BYBY 1976 631662
1977 631741
631745
GENERAL COMMENTS ON COLUMBIA RIVER STOCKS
Information On: Spring Creek Hatchery Stock (Model Stock #20)
Source: Chinook Technical Committee. 1988/89.
Historically, the Spring Creek fall chinook group has been one of the major contributors to chinook fisheries on the Washington coast and in the Columbia River. The escapement goal is 8,200 adults to the Spring Creek hatchery. This stock primarily returns to the Columbia River as three years old.
The Spring Creek chinook stock was selected based on significant contributions to all west coast troll fisheries from Cape Falcon up to the north end of Vancouver Island. In addition, it represents a major production group from the Columbia River. This stock is one of the four original harvest rate indicator stocks used in the multi-stock model for the US-Canada negotiations.
Spring Creek CWT Codes
BY 77 055501
055601
055701
056001
056201
BY 78 050433
050434
050444
050446
The estimated CWT escapement (ESC) recoveries were expanded using estimated stray rates. The number of Spring Creek hatchery chinook straying below Bonneville dam are estimated from CWT recoveries at lower river facilities. The number of Spring Creek hatchery stray fish above Bonneville dam are estimated through run reconstruction, which uses catch, hatchery returns and Bonneville dam adult counts.
GENERAL COMMENTS ON COLUMBIA RIVER STOCKS
Information On: Lower Bonneville Hatchery Tule Fall (Model Stock #21)
Source: Chinook Technical Committee. 1988/89.
Within the broad group of Lower River Hatchery (LRH) stocks, there are three different subunits identified as Willamette River, Cowlitz Hatchery and all other LRH facilities. The LRH adult return has averaged about 150,000 fish between 1970-1984. The composite LRH spawning escapement goal is 35,000 adults. The goal is based on hatchery brood stock requirements.
Based on CWT recoveries, LRH fall chinook appear to significantly contribute to Canadian fisheries. However, Cowlitz fall chinook demonstrate a more northerly catch distribution than other LRH stocks. Cowlitz hatchery fall and Bonneville hatchery tule fall chinook stocks were incorporated to improve accounting of fisheries contribution (for LRH chinook production), in the 1986 version of the model.
Cowlitz Fall CWT Codes
BY 77 631802
BY 78 631942
BY 79 632137
632154
Bonneville Tule Fall CWT Codes
BY 76 091605
BY 77 071656
BY 78 071842
BY 79 072157
072163
GENERAL COMMENTS ON COLUMBIA RIVER STOCKS
Information On: Cowlitz Hatchery Tule Fall (Model Stock #22)
Source: Chinook Technical Committee. 1988/89.
Within the broad group of Lower River Hatchery (LRH) stocks, there are three different subunits identified as Willamette River, Cowlitz Hatchery and all other LRH facilities. The LRH adult return has averaged about 150,000 fish between 1970-1984. The composite LRH spawning escapement goal is 35,000 adults. The goal is based on hatchery brood stock requirements.
Based on CWT recoveries, LRH fall chinook appear to significantly contribute to Canadian fisheries. However, Cowlitz fall chinook demonstrate a more northerly catch distribution than other LRH stocks. Cowlitz hatchery fall and Bonneville hatchery tule fall chinook stocks were incorporated to improve accounting of fisheries contribution (for LRH chinook production), in the 1986 version of the model.
Cowlitz Fall CWT Codes
BY 77 631802
BY 78 631942
BY 79 632137
632154
Bonneville Tule Fall CWT Codes
BY 76 091605
BY 77 071656
BY 78 071842
BY 79 072157
072163
GENERAL COMMENTS ON COLUMBIA RIVER STOCKS
Information On: Lewis River Wild Stock (Model Stock #23)
Source: Chinook Technical Committee. 1988/89.
The lower Columbia River fall wild chinook adult returns have averaged 36,000 for the years 1970 through 1980. Approximately 85 percent of the adult escapement was to the north fork of the Lewis River. At present, there is no calculated escapement goal for Lewis River wild fall chinook. However, the 1970-1980 average was 10,000 adults, which is an approximate escapement target.
CWT recoveries for the North Lewis River wild stocks indicate that the majority of the harvest takes place in Alaska and British Columbia. The Lewis River wild chinook is the only Columbia River indicator stock that is not tagged at a hatchery facility. This stock was not represented in the 1984 version of the multi-stock model.
BY 77 631611
631618
631619
BY 78 631813
631920
631858
631902
631859
632002
GENERAL COMMENTS ON COLUMBIA RIVER STOCKS
Information On: Willamette River Spring Stock (Model Stock #24)
Source: Chinook Technical Committee. 1988/89.
The recent ten year average for terminal adult returns has been 66,300. The returning population is estimated to be composed of approximately 25 percent naturally spawning chinook. The current escapement goal is 30,000 fish at Willamette Falls. Only once in the past ten years has the current escapement goal not been achieved. Willamette spring chinook appear to have a far northerly distribution as demonstrated by coded-wire-tag (CWT) recoveries.
The stock was chosen as an indicator stock in the model based upon its significant contribution to Alaskan and Canadian fisheries. In addition, this stock was added to the model in order to represent lower Columbia River spring chinook stocks.
BY 76 091621 through 091631
091701 through 091703
BY 77 071737
071738
071741
071742
BY 78 071925
072042
072047
072049
072053
BY 79 072219
072226
072302
072252
072253
072254
GENERAL COMMENTS ON COLUMBIA RIVER STOCKS
Information On: Spring Cowlitz Hatchery Stock (Model Stock #25)
Source: Chinook Technical Committee. 1988/89.
The spring chinook that return to the Cowlitz and nearby Washington tributaries are dominated by hatchery production, although about 5 percent of the production spawns naturally. The Cowlitz spring stocks averaged 10.5 percent of the spring chinook return to the Columbia for the years 1970 through 1979. From 1980 to 1985, the Cowlitz spring stocks averaged 20.5 percent of the spring chinook returning to the Columbia. The adult spawning escapement goal is about 2,500, which is based on brood stock requirements.
This stock was selected as a harvest rate indicator stock based on its significant contribution to Canadian fisheries. This type of spring stock was not included in the 1984 version of the multi-stock model.
The 1977 brood year had a large enough number of tags released to confidently estimate the base period exploitation pattern. The other tag releases during the base period were either very small or experimental groups not representative of the facilities production.
BY 77 631817
631818
GENERAL COMMENTS ON COLUMBIA RIVER STOCKS
Information On: Columbia River Summer Stock (Model Stock #26)
[No information available at this time.]
Information On: Oregon Coastal Stocks (Model Stock #27)
Source: Chinook Technical Committee. 1988/89.
The Oregon coastal stock included in the model representS far northerly migrating production. Oregon stocks which remain within Washington, Oregon, and California fisheries are not included within the model.
Escpmnt Avg. Escpmnt
Production Unit Goal 1979-81 1975-78
Oregon Coastal Natural 45,000 69,733 64,600
Tag codes selected were from brood years 1976, 1977, and 1978.
Brood Year 1976 1977 1978
Brood Weight 1.000 1.102 2.078
Tag Code 091637 071643 071849
091638 071644 071850
Information for each tag code on the return to the hatchery rack was provided by Ron Williams of the Oregon Department of Fish and Wildlife. He also noted that studies conducted in the Salmon River in 1986 and 1987 indicated that the stray rate was approximately 3:1, and that the freshwater sport fishery (for which no recovery data was available) had a harvest rate of approximately 20 percent. To account for the unsampled returns, the rack return was multiplied by a factor of 4 and the freshwater sport catch was set equal to the observed rack return.
Escapement estimates were also supplied by Ron Williams.
Information On: Washington Coastal Wild Fall Stock (Model Stock #28)
Source: Chinook Technical Committee. 1988/89.
CWT releases during the 1977-79 brood year base period for Washington coastal chinook stocks are limited. Only the Quinault system had a program during this period which tagged sufficient numbers of fish to yield results that were judged suitable for modeling purposes. It was felt, however, that this stock could only represent the Quinault system and CWT results should not be extrapolated to represent other coastal stocks, primarily due to the introduction of non-native stocks to the system in the early 1970's.
Escpmnt Avg. Escpmnt
Production Unit Goal 1980-81
Quinault Hatchery 5,000 2,350
The average escapement for 1980-81 was used rather than 1979-81 as escapement data for 1979 was not available.
The following tag codes were used to model the Quinault fall hatchery stock:
Brood Year 1977 1978
Catch 218 1,180
Brood Weight 5.4128 1.0000
Tag Codes 050337 050338
050518
050519
Adjustments to escapement CWT recoveries are based on in-river catch to escapement ratios obtained from PFMC and QDNR records (PFMC Review of 1985 Fisheries; Table B-28 and personal communication from Delbert Boyer, QDNR (1/27/87).
Net
Year Catch Escpmnt Ratio
1980 4.4 2.1 2.0952
1981 5.3 2.6 2.0385
1982 5.5 2.9 1.8966
1983 4.4 2.2 2.0000
Mean 2.0076 = 2.0
To adjust for potential underestimation of escapement recoveries due to water flow problems at the Quinault National Fish Hatchery, we applied this 2:1 ratio to the age 3-5 Washington coastal net catch in order to obtain an estimate of escapement by age class. This ratio is based on the average catch: escapement ratio reported for fall chinook in the Quinault system during the period 1980-83 when adult recoveries of the above CWT groups occurred.
The Quinault stock, like most of the other chinook stocks on the Washington Coast, exhibits a far-northerly migration pattern and is harvested mainly in SE Alaska and Northern BC in addition to terminal area net fisheries.
GENERAL COMMENTS ON PUGET SOUND/WASHINGTON COASTAL STOCKS
Information On: Lyons Ferry Stock (Model Stock #29)
[No information available at this time.]
Information On: Mid-Columbia River Brights Stock (Model Stock #30)
[No information available at this time.]
GENERAL COMMENTS ON PUGET SOUND/WASHINGTON COASTAL STOCKS
Modifications to the 1986-87 version of the multi-stock model included a number of revisions to the input data for Puget Sound and Washington coastal stocks. The major modifications which were made are summarized below:
The Nooksack Spring, Skagit Summer, Stillaguamish Summer, and Snohomish Fall stocks were included in the model primarily to evaluate the effects of alternative management actions upon the rate of rebuilding. Other stocks were included primarily to provide realistic catch levels in model fisheries.
Puget Sound hatchery chinook releases are characterized by a diverse number of release times and sizes. Many of these production components were not tagged during the base period of the model. One approach to overcome this situation would be to identify individual production components within a stock and assign tag groups to these production components based on measurable characteristics of the population. Lacking well-defined criteria with which to accomplish this and wishing to minimize the number of assumptions involved in this analysis, we opted to pool CWT results from all representative tag groups within a brood year, i.e. simply treat individual experiments as if they were part of one large tag release. Cluster analysis indicated that releases within a production region had a similar pattern of distribution.
After combining tag groups within brood year, we weighted each brood year in order to give it equal representation. Our objective was to generate a composite or average picture of the stock's performance during the base period, discount annual harvest differences, and avoid reliance on extreme results. Weighting between brood years was accomplished by standardizing the catch level for each brood, i.e. scaling the total catch (excluding escapement) to some arbitrary level, in this case, maximum total brood year catch. In some instances, there was only one brood year available for a stock and this step was omitted.
Two further adjustments were necessary to transform the CWT recoveries into input data usable by the model. First, because CWT recoveries in the escapement are generally underestimated, we applied correction factors in the form of terminal net catch escapement ratios to estimate the expected escapement recoveries for a stock (catch and escapement data were obtained from the WDF run reconstruction dated 7/21/86). The total recoveries in the North Puget Sound Net and Other Puget Sound Net fisheries of tags from fish of age 3 through 5 were multiplied by the average catch/escapement ratio to obtain the expected escapement for the tag groups.
Second, the Puget Sound fall fingerling, Puget Sound fall natural, and Puget Sound yearling are stock aggregates which consist of a number of distinct stocks. For example, the Puget Sound yearling stock aggregate includes production from the Skagit River, the Snohomish River, South Puget Sound, and Hood Canal. Since the stock aggregate should reflect the relative abundance of each component, it was necessary to weight the CWT recovery estimates for each stock to obtain the correct mixture within the stock aggregate. To accomplish this, a scale factor was computed based on the ratio of total escapement to the CWT escapement estimates.
GENERAL COMMENTS ON COLUMBIA RIVER STOCKS
Chinook populations entering the Columbia River are divided by return timing into spring, summer and fall segments. The spring and fall returns are divided into management units on the basis of ocean distribution as well as spawning time and age at maturity.
The multi-stock model harvest rate indicator stocks, representing the Columbia River chinook populations, did not cover all segments. The summer segment and the upper river spring management unit were not represented due to insufficient numbers of coded wire tagged hatchery smolts released for these stocks. In most cases, tag codes were selected which had a release of at least 100,000 coded wire tags. All the Columbia River tag codes used in the model were representative of production and no experimental tag release groups were used.