Alaskan Salmon Research Articles

Patterns of intra- and inter-population genetic diversity in Alaskan coho salmon: Implications for conservation

Little is known about the genetic diversityof coho salmon in Alaska, although this arearepresents half of the species' North Americanrange. In this study, nine microsatellite lociwere used to genotype 32 putative coho salmonpopulations from seven regions of Alaska. Theprimary objectives were to estimate andevaluate the degree and spatial distribution ofneutral genetic diversity within and amongpopulations of Alaskan coho salmon. Geneticanalysis yielded four results that provideinsight into forces influencing geneticdiversity in Alaskan coho salmon and haveimportant conservation implications: 1)significant population differentiation wasfound within each region; 2) the degree ofdifferentiation (FST = 0.099) amongpopulations was as large or larger than thatreported for other Pacific salmon species inAlaska; 3) phenetic clustering of populationsshowed weak geographic concordance; 4) stronggenetic isolation by distance was only apparentat the finest geographic scale (within adrainage). These results suggest that cohosalmon populations are small relative topopulations of other Pacific salmon, and thegenetic diversity within and among coho salmonpopulations is influenced primarily by geneticdrift, and not gene flow. Resource managementand conservation actions affecting coho salmonin Alaska must recognize that the populationsare generally small, isolated, and probablyexhibit local adaptation to different spawningand freshwater rearing habitats. These factorsjustify managing and conserving Alaskan cohosalmon at a fine geographic scale.

"Well-Thinking Men and Women": The Battle for the White Act and the Meaning of Conservation in the 1920s

Historians have long debated the fate of the conservation movement during the 1920s. While all seem to agree that a sharp divide existed between conservationists and anti-conservationists, they have differed over whether conservation entered a Dark Age during these years, whether it was sustained by private organizations and radical amateurs, or signaled an era of continuity in relations between industry and the state. The battle over the 1924 White Act, a piece of federal legislation designed to protect dwindling Alaska salmon stocks, suggests that all these conclusions deserve reevaluation. While conservation hardly disappeared during the Republican ascendancy, it did undergo important changes as federal officials emphasized production-oriented concerns for efficiency over socially oriented concerns about equity. The heated debate that erupted over the White Act bared significant differences in how Americans defined the meaning of conservation at the time. The resulting policies, as many historians have noted, often benefited large producers over smallholders while accomplishing little in solving the underlying problems of waste and depletion.

Fisheries productivity in the northeastern Pacific Ocean over the past 2,200 years.

Historical catch records suggest that climatic variability has had basin-wide effects on the northern Pacific and its fish populations, such as salmon, sardines and anchovies. However, these records are too short to define the nature and frequency of patterns. We reconstructed approximately 2,200-year records of sockeye salmon abundance from sediment cores obtained from salmon nursery lakes on Kodiak island, Alaska. Large shifts in abundance, which far exceed the decadal-scale variability recorded during the past 300 years, occurred over the past two millennia. A marked, multi-centennial decline in Alaskan sockeye salmon was apparent from approximately 100 BC to AD 800, but salmon were consistently more abundant from AD 1200 to 1900. Over the past two millennia, the abundances of Pacific sardine and Northern anchovy off the California coast, and of Alaskan salmon, show several synchronous patterns of variability. But sardines and anchovies vary out of phase with Alaskan salmon over low frequency, which differs from the pattern detected in historical records. The coherent patterns observed across large regions demonstrate the strong role of climatic forcing in regulating northeastern Pacific fish stocks.

Effects of stock, coded-wire tagging, and transplant on straying of pink salmon (Oncorhynchus gorbuscha) in southeastern Alaska

Straying of pink salmon (Oncorhynchus gorbuscha) from two wild stocks (intertidal and upstream) in southeastern Alaska was estimated. Secondary factors (coded-wire tagging and transplanting of the intertidal stock) that may influence straying were also evaluated. In 1996, 321 494 fry were marked with either coded-wire tags or pelvic-fin clips. A total of 3828 marked adults were recovered in their natal streams and 79 strays were recovered in streams within 60 km of the release sites. The overall estimated straying rate was 5.1%. Estimated straying for the intertidal stock (9.2%) was higher than straying of the upstream stock (3.7%) but was not statistically different due to high variance of the estimates. The proportion of fish straying was significantly greater (P = 0.01) for coded-wire-tagged than for pelvic-fin-clipped fish for the upstream but not for the transplanted stock. Straying and distribution of the transplanted stock were more similar to those of the upstream stock, which was endemic to the natal watershed and release site of the transplant, than to those of the intertidal stock, which was the donor stock for the transplant. Although tagging may influence straying, incubation and initial estuarine environment appear to be major determinants of the natural straying of pink salmon in southeastern Alaska.

Disturbance of Small-Stream Habitat by Spawning Sockeye Salmon in Alaska

Abstract We examined how the spatially and temporally predictable disturbance caused by a spawning run of native sockeye salmon Oncorhynchus nerka temporarily affected benthic and invertebrate drift communities of two small streams in southwestern Alaska. Surface gravel size temporarily increased as a consequence of this mechanical disturbance, and periphyton biomass decreased in one stream. The postspawning rise in periphyton biomass in Bear Creek (larger sockeye salmon run) likely reflects nutrient release by decomposing sockeye salmon. Total benthic invertebrate and larval chironomid density decreased during spawning in one stream, but most invertebrate taxa in both streams did not exhibit clear spawning-related impacts. In contrast, invertebrate drift almost always increased during daylight hours when sockeye salmon were present, but it was difficult to separate mechanical effects of sockeye salmon acting via redd construction versus swimming. Total daytime drift density during spawning was four times...

Effects of stock, coded-wire tagging, and transplant on straying of pink salmon (<i>Oncorhynchus gorbuscha</i>) in southeastern Alaska

Effects of stock, coded-wire tagging, and transplant on straying of pink salmon (<i>Oncorhynchus gorbuscha</i>) in southeastern Alaska

Relationships between Alaskan salmon catch and North Pacific climate on interannual and interdecadal time scales

Using multivariate time series models, Alaska's statewide commercial catch of three salmon species during 1925-1994 is shown to be related to surface temperatures in particular large regions of the eastern North Pacific. Previous research has indicated that interdecadal changes in Alaskan catch levels are related to large-scale changes in the climate regime of the North Pacific. The present work focuses on interannual variability by controlling for climatic shifts in the mid-1940s and mid-1970s. For sockeye (Oncorhynchus nerka) and chum (O. keta), relationships with temperature occur within a few months after ocean entry with warmer regional temperatures enhancing survival. For sockeye and pink salmon (O. gorbuscha), relationships with temperature occur at the time and location of the return migration, suggesting that colder ocean temperatures may enhance spawning success or egg survival. In addition, the models show a significant positive relationship of chum catch to pink catch 2 years earlier, suggesting a common influence on smolts of the two species. The results support the contention that climatic factors affecting the marine environment play a significant role in salmon production on interannual, as well as interdecadal, time scales.

Relationships between Alaskan salmon catch and North Pacific climate on interannual and interdecadal time scales

Relationships between Alaskan salmon catch and North Pacific climate on interannual and interdecadal time scales

Recent events concerning Atlantic salmon escapees in the Pacific

Atlantic salmon (Salmo salar L.) escapees from commercial salmon farms in Washington State, USA, and British Columbia, Canada, arecaught in fisheries from Washington State to Alaska. A large escape from a farm near Cypress Island, Washington, was likely to have been the cause of increased abundance of Atlantic salmon in Juan de Fuca Strait and higher than average catches on the west coast of Vancouver Island during the summer of 1996. The catch of Atlantic salmon in Alaska in 1996 exceeded the sum of catches in all previous years. The number of escapees recorded in fresh water has been increasing, with more than 210 adult fish observed in 29 rivers in British Columbia during 1996. During the winter of 1995/1996, 39 Atlantic salmon were reported caught in the Salmon River on Vancouver Island. Analysis of the stomach contents of these fish indicated that some were feeding in fresh water.

Status of Pacific Salmon and Steelhead Escapements in Southeastern Alaska

We evaluated the status of Pacific salmon and steelhead (Oncorhynchus mykiss) in southeastern Alaska. Of 9,296 spawning aggregates identified in this region, some data were available for 4,009 (43%), and 928 (10%) had sufficient information to analyze for escapement trend. Of those analyzed, 333 (36%) were increasing, 556 (60%) were stable, 37 (4%) were declining, and 2 (< 1%) showed precipitous declines. We evaluated risk of extinction of spawning aggregates using criteria similar to surveys outside Alaska. We rated 918 (99%) at no or low risk, 8 (∼ 1%) at moderate risk, and 2 (< 1%) at high risk. No spawning aggregates were identified as extinct based on our evaluation of escapement data dating back to 1960. Prior to 1960, two spawning aggregates, one sockeye salmon (0. nerka) and one chum salmon (0. keta), were identified as extinct based on responses to a postal questionnaire. The Alaska Department of Fish and Game grouped spawning aggregates into management units for each species. Management units vary in number and size for each species. Of 141 management units defined, 129 (92%) had enough information to evaluate; all had stable or increasing escapement trends. However, escapement data for this study had limitations for two reasons. First, monitoring spawning aggregates for escapement in all spawning locations in southeastern Alaska is impractical; interpretations are based instead on estimates of key indicator streams (usually commercially important runs) in the region. Second, most escapement estimates are based on aerial surveys rather than more accurate methods such as weirs or sonar estimates. Our results, based on the limited data, indicated that Pacific salmon in the region were generally in good health at two levels of salmon population structure: spawning aggregates and management units. The small amount of escapement data for steelhead precludes a generalization about their status and overall health.

SALMON STOCK VARIABILITY AND THE POLITICAL ECONOMY OF THE PACIFIC SALMON TREATY

Since the mid‐1970s, changes in the marine environment along the west coast of North America and in the Northeastern Pacific appear to have greatly enhanced the productivity of Alaskan salmon runs while contributing to declining runs of some salmon spawning in Washington, Oregon, and California. These inverse fluctuations in northern and southern salmon stocks may have aggravated a recent break‐down in cooperation between the United States and Canada in setting harvest allocations under the Pacific Salmon Treaty. This paper examines the establishment of fishing regimes by the Pacific Salmon Commission. A game theoretic model is used to analyze the possible contribution of stock variability to the current conflict. Shifts in the parties' incentives to manage the fishery cooperatively, together with significant transaction costs, explain much of the recent difficulty in negotiating mutually acceptable fishing regimes. The paper concludes by addressing the question of whether the regime‐setting process can be made more resilient to such stresses.

Charles Henry Gilbert (1859–1928): An early fishery biologist and his contributions to knowledge of pacific salmon (oncorhynchusspp.)

Abstract Charles Henry Gilbert (1859–1928) was a pioneering ichthyologist and an early fishery biologist of particular significance to the fisheries of the west coast of the U.S. As chairman of the Zoology Department of Leland Stanford Junior, University in Palo Alto, CA, from 1891 to 1925, Gilbert became increasingly interested in the biology of Pacific salmon (Oncorhynchus spp.). His studies of the use of scales to age salmon (ca. 1909 to 1912) led to his research on these fishes for the British Columbia Provincial Fisheries Department (1912 to 1924) and for the U.S. Bureau of Fisheries, mainly in Alaska, from about 1917 to 1927. He pioneered racial studies on salmon using the scale method, was instrumental in establishing sound tagging programs on salmon in Alaska to define their migratory patterns, and was one of the very first scientists to consider the population dynamics of northwest stocks of Pacific salmon. Above all, Gilbert was an ardent conservationist who warned both the salmon‐canning industry of the Pacific coast and government authorities of the severe dangers to the resource by unrestrained fishing.

The Alaska Salmon Fishery:

Historically, the Alaska salmon industry has been a model of success. Years ago, when historical stocks were diminishing, salmon habitats were saved and salmon populations were increased through the world's most productive hatchery system. In 1993, the Alaska salmon harvest reached a historic high. However, in the same year, real salmon prices continued their five-year decline and ended at all-time lows. Success in regulating supply has been offset by a near complete disregard for the growing competition from farmed fish and for changing demand patterns. Today, the Alaska salmon industry desperately needs innovations in demand-related fields such as product design, quality control, marketing, and so forth. Without an increased awareness of competition and the changing consumer, the Alaska salmon industry will continue to see continued industry hardship and more decreasing profits than it ever imagined possible just a few years ago.

A Revenue Analysis of the Alaska Pink Salmon Fishery

Abstract The Alaska salmon industry is suffering from declining prices due to an increasing supply of salmon worldwide, This has led to a much-needed economic evaluation of the Alaska salmon enhancement program and especially of the hatchery system for pink salmon Oncorhynchus gorbuscha. An econometric model of world salmon markets was used to evaluate possible future pink salmon enhancement production scenarios, as requested by the Alaska State Legislature and the Alaska Department of Fish and Game, Results of this model, based on point estimates, indicate that if pink salmon production for enhancement were decreased, revenues to pink salmon fishers in Alaska would rise, although there would be regional differences. However, a complete elimination of the Alaska salmon enhancement program would decrease revenues.

Biological interactions of natural and enhanced stocks of salmon in Alaska

A workshop on ‘Biological interactions of natural and enhanced stocks of salmon in Alaska’, was held in autumn 1991 at the Prince William Sound Science Center in Cordova, AL, USA. The subject and site were relevant as the impacts of hatchery operations on wild salmon stocks have recently become an international concern and Prince William Sound contains one of the largest salmon hatchery operations in the world. This workshop was designed to review the evidence, or lack thereof, that hatchery salmon are affecting the growth, survival, and natural genetic diversity of wild salmon in Alaska. International, national, and regional perspectives identified the important biological interactions between hatchery and wild salmon stocks, and characterized them in terms of genetics, carrying capacity, and harvest management. The workshop participants unanimously agreed on the importance of ‘maintaining genetic diversity within and between natural populations of salmon to sustain productivity of both wild and enhanced stocks’. An expansion of stock assessment and identification research and monitoring programs using new technologies (acoustics, optics, electronic mapping, marking, and gene sequencing) is the key to the acquisition of information needed to protect wild stocks from future over-exploitation.

Using an International Econometric Model to Forecast Alaska Salmon Revenues

As Alaska prices tumbled in the 1990s, Alaska's Senate Special Committee on Domestic and International Commercial Fisheries requested a comprehensive review of the Alaska salmon enhancement program. As part of this review, a revenue analysis was performed to examine the effects of various salmon enhancement production levels on future revenue generated to salmon fishers working in Alaska waters. The results were then used in a cost/benefit analysis of the state's enhancement program for sockeye, chinook, coho, chum, and pink salmon. This report focuses on the two most important Alaska salmon species, sockeye and pink. Results of the revenue analysis indicate that for sockeye salmon, future revenues would increase if output from salmon enhancement were expanded. For pink salmon, revenues would decrease if salmon enhancement were expanded and increase if salmon enhancement were scaled back. However, a complete elimination of the pink hatchery program would decrease revenues. For both species, there are important regional differences.

Comparison of the effects of adding fish high or low in n-3 fatty acids to a diet conforming to the dietary guidelines for Americans

Objective To compare the effects of diets containing high or low amounts of n-3 fatty acids on lipid levels in men. Design A continuous 40-day feeding study was conducted using a 5-day cycle menu. The control diet, which was fed the first 21 days of the trial, contained 32% of energy as fat and 44.4 total dietary fiber per day. Total serum cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TGs) were evaluated 1 day before the trial began and on days 21 and 41. Subjects 17 men aged 21 to 42 years who were free-living individuals with no apparent illnesses of hyperlipidemia. Intervention The treatment diets, which were substituted daily for the regular entrees for the last 19 days of the trial, contained 180 g/day of either farm-raised catfish or wild Alaskan salmon. Statistical analyses performed Serum data were analyzed using analysis of covariance with the initial values as the covariates. Results After 21 days on the control diet, TC and TGs decreased; however, there were no further decreases during the last 19 days when fish was consumed. LDL-C remained unchanged after the first 21 days but was lower than the initial value by day 41. HDL-C levels were similar over the 40 days. There were no significant differences in lipid levels of men who consumed catfish and those who consumed salmon. Applications/conclusions Farm-raised catfish compared favorably to wild Alaskan salmon when incorporated into the total diet in regard to lipid levels in men.

Inventory Dissipation in the Japanese Wholesale Salmon Market

Many fisheries are characterized by a brief and concentrated harvest period followed by a longer marketing period during which the stored product is sold out of inventories. This paper develops an economic model of optimal inventory dissipation for a semi-perishable product which assumes that decision makers plan allocations of inventoried product to the wholesale market over the marketing period in a way that maximizes expected net returns. The model is applied to the Japanese wholesale salmon market. The Japanese market fits the characteristics described above in that inventoried holdings of frozen salmon are established to a large extent from imports during a relatively brief period corresponding to concentrated runs of sockeye salmon in Alaska. Results indicate that supply behavior from inventory stocks can be explained by current and expected future prices, the opportunity cost of holding stocks, the length of time left in the marketing horizon and the level of current inventory.

Commercialization of fisheries and the subsistence economies of the Alaska Tlingit

Abstract The commercialization of salmon in southeast Alaska has affected the traditional subsistence economies of the Tlingit Indians. Over the past hundred years, a mixed subsistence‐market economy that combines subsistence and market sectors has developed in Tlingit communities. Contemporary fishing households in two Tlingit communities are shown to participate in both subsistence and commercial fisheries using various strategies. In the 1980s, commercial salmon fishing households produced more subsistence fish and game than households without commercial permits. Certain factors in commercial fisheries development have exerted negative pressures on the traditional subsistence sector of the Tlingit economy: stock depletions; non‐local, non‐Native control of the fisheries; and restrictive subsistence fisheries management regimes. Resolution of these problems for the Tlingit depends on influencing historic processes stemming from legal and political structures that are not culturally responsive to indigen...

SALMON SURVIVE OIL SPILL

When the Exxon Valdez hit the rocks of Prince William Sound last year, there were predictions of a near-apocalypse for Alaska's salmon industry. Well, this year's salmon catch is coming to an end and it turns out it will be the biggest in history... So far, the Washington Post reports that 40 million salmon have been caught, far outstripping the 1987 record harvest of 29 million. Many of the salmon were hatched last spring in the very waters fouled by the Exxon Valdez oil spill. The rest were released from hatcheries in Prince William Sound and swam through the same waters on their way to the ocean. At the largest hatchery in the area, the number of pink salmon returning to the sound this summer was double the average of recent years. Last year's oil spill apparently had little effect on the growth of plankton in the sound, the main source of food for young salmon. Salmon hatcheries report plankton growth was better than ever this year.