Alaska Department of Fish and Game
Commercial Fisheries Management and Development Division
Anchorage, AK 99518-1599
ABSTRACT Prince William Sound has always been an important salmon production area of Alaska. Wide fluctuations in the annual wild stock production levels have been a characteristic of the Sound. Supplemental production of hatchery-produced pink Oncorhynchus gorbuscha, sockeye O. nerka, coho O. kisutch, chum O. keta, and chinook salmon O. tshawytscha offer additional opportunities for commercial, sport, personal use, and subsistence fishermen in Prince William Sound. The salmon enhancement program in the Sound is the largest and one of the most successful in Alaska. The Prince William Sound Aquaculture Corporation operates five hatcheries, and another is operated by the Valdez Fisheries Development Association. Hatchery stock return rates have fluctuated from year to year. To allow hatchery produced fish in the fisheries to be identified, large numbers of juvenile salmon are tagged each spring prior to their release. Tags are recovered in the fisheries, and estimates of hatchery contribution are tabulated. In years when wild stock production was weak, protection was offered by restricting the fisheries on these stocks. A regional planning team coordinates the hatchery program direction. State law requires a detailed review and approval process for all fish transports; this includes a review by State fisheries management, genetics, and pathology staff. Annual hatchery production and evaluation plans are developed jointly by the operators and fishery managers to determine program needs and direction. Proposed hatchery production increases require a permit alteration request that is reviewed by both the Alaska Department of Fish and Game and the regional planning team.
BACKGROUND Prince William Sound is an important salmon producing region for Alaska. The Sound is a semi-protected body of saltwater with openings to the Gulf of Alaska. It is rimmed by glacial fjords and largely undisturbed upland habitat. The communities of Cordova, Tatitlek, Valdez, Whittier, and Chenega are located around the Sound. There are more than 1,100 coastal streams and a number of lakes that are used by salmon for spawning and rearing habitat. The Copper River, a large glacial system flowing from Alaskas interior, empties into the Pacific Ocean near Cordova. Six species of salmon inhabit the rivers, streams, lakes, and coastal waters of Prince William Sound. Pink salmon is most abundant. The Copper River is known for its sockeye and chinook salmon. Chum salmon occur in a number of areas, and coho are scattered throughout the Sound. Rainbow trout/steelhead (Onchorhynchus mykiss) also inhabit the area bu are not abundant.
Commercial salmon fishing for pink, sockeye, chum, coho, and chinook salmon has long been a mainstay of the Prince William Sound economy. Fish are harvested by both seine and gillnet gear. Salmon sport fisheries are important in accessible areas near Cordova, Valdez, and Whittier. Subsistence and personal use fisheries are important to local residents as a source of food and particularly important to the Native Alaskan villages of Tatitlek and Chenega in the Sound as well as communities along the Copper River drainage.
Salmon are critical in the Prince William Sound ecosystem, as they represent a primary food source at their various life stages for a wide variety of birds, fish, and mammals. Similarly, the salmon depend on the productivity of the Sound for food during their migrations as juveniles and adults. The 1989 Exxon Valdez oil spill was a landmark event in Prince William Sound that impacted the ecosystem, the communities, and the fisheries.
HATCHERIES AND WILD STOCKS
The Prince William Sound Aquaculture Corporation (PWSAC) operates five hatcheries in this area. The Armin F. Koernig Hatchery began production in 1976 and produces pink salmon. The Cannery Creek Hatchery also produces pink salmon and has been operating since 1978. The W.F. Noerenberg Hatchery began production in 1986 and produces pink, chum, coho, and chinook salmon. The Main Bay Hatchery began production in 1983 and currently produces sockeye salmon. The Gulkana facility, located in the upper Copper River basin, began sockeye salmon fry releases in 1974. The Valdez Fisheries Development Association (VDFA) operates the Solomon Gulch Hatchery near Valdez which produces pink, chum, and coho salmon. The program at this facility began in 1979 (Kron and Suzumoto 1989). In 1992, these facilities collected a combined total of 677.5 million pink salmon eggs, 132.2 million chum salmon eggs, 29.1 million sockeye salmon eggs, 4.7 million coho salmon eggs, and 1.3 million chinook salmon eggs. This represents more than half of the statewide egg take by hatcheries in Alaska. The adults returned to Prince William Sound hatcheries in 1992 totalled 8.6 million pink salmon, 0.7 million sockeye salmon, 0.4 million chum salmon, 0.2 million coho salmon, and 2,500 chinook salmon (McNair and Holland 1993).
In Alaska, wild stocks of salmon provide the foundation for the salmon industry. Wild stock conservation receives a priority in fishery management decisions. Alaska has strict fish genetics and pathology regulations and policies to protect wild stocks as well as the hatchery program. Decisions regarding permits for hatchery programs have included fishery managers, technical staff, and the public from its inception. Comprehensive regional planning has provided the direction for the hatchery production program; this is a cooperative effort involving the Alaska Department of Fish and Game (ADF&G), PWSAC, VFDA, the U.S. Forest Service, other agencies and interest groups, and the general public. Each year fishery managers and hatchery operators coauthor and sign off on a detailed plan for hatchery operations, egg takes, releases, evaluation, and adult return management. This program control document is the primary mechanism for conflict resolution. Even with all the planning, co-development of control documents, and joint discussions, hatchery-wild stock considerations continue to be a focal point for discussion and debate.
ADF&G mnitors wild pink salmon stocks in approximately 200 index streams using aerial surveys when adults are spawning and, in addition, conducts foot surveys (personal communication, T.M. Willette, ADF&G, P.O. Box 669, Cordova, Alaska, 1993). Weirs are operated on a number of systems to enumerate adult and juvenile salmon migrations. Salmon spawning streams are sampled in late winter to evaluate the over-wintering survival rate of eggs to fry in the gravel. Other cooperative research programs with the University of Alaska and the hatchery operators include estuarine plankton monitoring and juvenile salmon migration studies.
Fishery management decisions have become an increasingly complex process. For example, when there is a lack of understanding of temporal and spatial distribution of different stocks, management errors can result. If hatchery stocks are overharvested, the economics of the hatchery are seriously affected. Alternately if managers mistake hatchery production for wild stock production, wild stock may be overharvested.
Tagging programs have been in place in Prince William Sound since 1984 and have become a useful tool for estimating hatchery pink salmon contributions in the fisheries (Geiger and Sharr 1990, Peltz and Geiger 1990, Peltz and Miller 1990). In recent years, more than 1 million juvenile salmon have been adipose clipped and wire tagged annually in the Sound to assess hatchery contributions to the total adult return (personal communication, T.M. Willette, 1993). This allows fishery managers to determine the mix of hatchery and wild stocks taken in the fishery. Along with other inseason indicators, results from tagging studies are used to direct the harvest while providing for wild stock escapement, hatchery cost recovery, and broodstock needs. Wild stock escapement is a top priority by state law. There is interest in mass marking (i.e., thermal marking of otoliths) to better evaluate hatchery contributions.
ADF&G has a mixed record in meeting wild stock pink salmon escapement goals. The longstanding wild stock pink salmon escapement goal for Prince William Sound is 1.35 million fish (personal communication, H.J. Geiger, ADF&G, P.O. Box 25526, Juneau, AK 1993). In a 17-year period (1960-76) prior to the hatchery program, estimates of the wild stock pink salmon escapement averaged 1.8 million fish annually (range 0.6-3.2 million) (Eggers et al. 1991). The escapement was less than the 1.35 million goal in 4 of the 17 years (Fig. 1). Since the initiation of the hatchery program, the wild stock escapement goal was achieved every year through 1992, and the escapement has averaged 2.6 million fish (range 1.4-6.1) (Fig. 1). It should be noted, however, that all indications are that the escapement will not be achieved with the run failure this season. We expect to come in at 70-80% of the wild stock escapement goal (personal communication, T.M. Willette, 1993). Quality of escapement is another issue of concern; while the overall numerical escapement goal may be achieved in a given year, escapements may be inadequate in some districts of the Sound. There are also concerns about hatchery fish straying to nearby streams and the potential impact this may have on wild stocks (Eggers et al. 1991).
Achievement of wild stock escapement goals is an ongoing challenge that ADF&G faces. The success of the hatchery program in Prince William Sound is dependent on the maintenance of healthy wild stocks of salmon. It appears that the run strength of pink salmon is impacted by estuarine water temperatures in spring with warmer years contributing to higher marine survival (Willette and Cooney 1991, Willette 1991). Returns of both wild and hatchery fish fluctuate greatly from year to year. In situations where wild stocks are weak and hatchery stocks are strong, fishing has been restricted to terminal areas immediately in front of the hatcheries thereby reducing the harvest rate on wild stocks (Fig. 2) (Eggers et al. 1991). While this is an effective tool from a wild stock resource conservation perspective, it is not popular with fishermen and processors.
Pink salmon wild stock escapement estimates for Prince William Sound as a whole have been based n aerial surveys of index streams and estimates of stream life of spawners. Recently, more detailed district evaluations of stream life have yielded a more complete assessment of this characteristic than was available previously. Based on this new data, it is apparent that we may have been underestimating wild stock escapement and overestimating the exploitation rates for pink salmon wild stocks (personal communication, T.M. Willette, 1993). This being the case, wild stock harvest rate determined from Eggers et al. (1991) shown in Figure 2 would be reduced further.
During the period 1960-76 when the pink salmon fishery was supported wholly by wild stocks, the average pink salmon catch in Prince William Sound was 3.3 million fish (Eggers et al. 1991). The catch fluctuated from 0.1 to 7.3 million fish (Table 1). Since hatchery releases were begun, the average pink salmon catch has been 19.7 million fish and has ranged from 2.9 to 50.8 million (Table 1). It should be noted that the increase is not only due to hatchery production but also to an increase in wild stock productivity. It appears that environmental conditions were favorable for pink salmon survival during the late 1970s and early and mid 1980s. Between 1977 and 1992, the survival rate from fry to adult return for hatchery produced pink salmon has ranged from 11.2 to 1.3% and has averaged 5.3% (Fig. 3) (Eggers et al. 1991; personal communication, H.J. Geiger 1993). In recent years, wild stock salmon production levels have dropped down to levels found during the 1960s and early 1970s. There are concerns that the Prince William Sound ecosystem has been out of balance since the 1989 oil spill. This years pink salmon return has been a disaster with a failure of wild and hatchery runs alike. The wide fluctuations in the pink salmon run that occurred prior to hatchery construction and are present now as well.
SUMMARY
ADF&G has a responsibility to achieve satisfactory wild stock escapements for all stocks and species. This, however, is very difficult given the fluctuations in the size of the runs, the nature of the fishery, and the mixture of the stocks taken. While tagging has been implemented since the inception of the Prince William Sound hatchery program, a renewed commitment to a joint tagging-recovery effort this year represents progress in state-private cooperation to collect basic information for the management of the salmon fishery. New information for other species is also critical. Tagging projects for wild and hatchery produced sockeye salmon stocks are providing greater insight into their distribution and vulnerability to various fisheries. These insights will allow ADF&G to improve protection of wild salmon stocks in the future and help assure that escapement goals are met for the future of salmon fisheries in the Sound.
It is clear that healthy wild stocks are a prerequisite to a successful hatchery program and a healthy economy in Prince William Sound.
ACKNOWLEDGMENTS
I would like to thank John McMullen and Mark Willette for editing this report. Id also like to thank Jamie Simmons, Heather Denning, and Lisa Seeb for their help with the figures and typing.
LITERATURE CITED
Eggers, D.M., L.R. Peltz, B.G. Bue, and T.M. Willette, 1991. Trends in the abundance of hatchery and wild stocks of pink salmon in Cook Inlet, Prince William Sound, and Kodiak Island, Alaska. Can. Spec. Pub. Fish. Aquat. Sci.
Geiger, H.J., and S. Sharr, 1990. The 1988 tag study of pink salmon from the Solomon Gulch Hatchery in Prince William Sound, Alaska. Fishery Research Bulletin 90-2:18-33, Alaska Department of Fish and Game, Division of Commercial Fisheries, P.O. Box 3-2000, Juneau, AK.
Kron, T.M., and B. Suzumoto, 1989. Partnerships in fisheries enhancement - An Alaskan success story. Alaska Fish and Game. March-April issue, pp. S-1 to 8.
McNair, M., and J.S. Holland, 1993. FRED 1992 Annual Report to the Alaska State Legislature. Number 127. Alaska Department of Fish and Game, Fisheries Rehabilitation, Enhancement and Development Division, P.O. Box 25526, Juneau, AK.
Peltz, L., and H.J. Geiger, 1990. A tagging study of the effects of hatcheries on the 1987 pink salmon fishery in Prince William Sound, Alaska. Fisheries Research Bulletin 90-02:1-17. Alaska Department of Fish and Game, Juneau, AK.
Peltz, L., and J. Miller, 1990. Performance of half-length coded wire tags in a pink salmon hatchery marking program, pp. 244-252. In: Fish marking techniques: American Fisheries Society Symposium 7. N. Parker, A.E. Giorgi, R.C. Heidinger, D.B. Jester, Jr., E.D. Prince, and G.A. Winans (eds.). American Fisheries Society, Bethesda, MD.
Willette, T.M., 1991. Cross correlations between sea surface temperature anomalies in the North Pacific Ocean and pink salmon (Oncorhynchus gorbuscha) returns to southern Alaska. Unpublished manuscript, Alaska Department of Fish and Game, FRED Division, P.O. Box 669, Cordova, AK 99574.
Willette, T.M., and R.T. Cooney, 1991. An empirical orthogonal functions analysis of sea surface temperature anomalies in the North Pacific Ocean and cross correlations with pink salmon (Oncorhynchus gorbuscha) returns to southern Alaska. In: B. White and I. Guthrie (eds.), Proceedings of the 15th Northeast Pacific Pink and Chum Salmon Workshop, February 27-March 1, 1991, Parksville, British Columbia, pp. 111-121.
