Alaska Fishery Research Bulletin Issues, Vol.1 No. 1 - Summer 1994
Handling Increases Mortality of Softshell Dungeness Crabs Returned to the Sea
Gordon H. Kruse, David Hicks, and Margaret C. Murphy - Vol. 1(1):1-9. 1994.
Effects of carapace hardness and air exposure duration on mortality were studied on Dungeness crabs Cancer magister off Kodiak Island, Alaska. We captured 516 legal male crabs and marked them with spaghetti tags. Carapace condition was recorded, and crabs were randomly selected for exposure to air for 5, 15, 30, and 60 min. Crabs were then returned to the sea. Subsequent recoveries from commercial catches included 11% of the tagged softshell crabs and 20% tagged hardshell crabs; these differences were statistically different. No statistical difference was found among exposure periods for hardshell crabs; low statistical power due to small sample size precluded similar tests for differences among exposure periods for softshell crabs. Low recovery rates of softshell crabs in Alaska is consistent with previous mark-recapture studies of Dungeness crabs conducted off Oregon and Washington. Previously published results from controlled experiments support our conclusion that differential recovery rates were primarily due to elevated handling mortality of softshell crabs. Our data suggest that softshell crabs experienced 45% higher mortality than hardshell crabs. However, this rate may not be representative of handling mortalities experience during commercial fisheries because (1) during molting periods fisheries catch crabs much softer than those we encountered, (2) We handled crabs much more carefully than would normally occur during commercial operations, and (3) we were unable to derive separate estimates of differential natural and handling mortalities among softshell and hardshell crabs. Findings of handling mortalities of softshell crabs, coupled to considerations of cannibalism in crab pots, indicate that Dungeness crab fishing seasons in Alaska should be structured to avoid major molting periods as is the general practice along the coasts of California, Oregon, Washington and British Columbia. Such regulations will reduce mortality and commensurately increase the abundance of harvestable males and spawning biomass. Extended fishery closures until several months after molting will result in some economic benefits, as well. Meat yield and wholesale value are lowest during molting and increase until peaking several months later. These factors, plus other socioeconomic tradeoffs, should be weighed to determine net benefits to changes in fishing seasons for Dungeness crabs.Full Article (PDF 85 kB)
A Summary of 1982-1991 Harvest, Escapements, Migratory Patterns, and Marine Survival Rates of Coho Salmon Stocks in Southeast Alaska
Leon Shaul - Vol. 1(1):10-34. 1994.
Wild juvenile coho salmon Oncorhynchus kisutch were coded wire tagged in three Southeast Alaska streams: Berners River, Ford Arm Lake, and Hugh Smith Lake. Returning adults were enumerated and sampled to estimate total escapement, fishery contribution, removal rates, migratory patterns, age structure, and survival rates. The primary purpose of the program was to index fishery harvest rates and patterns and determine factors affecting adult production. The estimated average harvest rate for the three indicator stocks by the Alaska troll fishery during the 1982-90 period was relatively stable, ranging from a low of 38.1% in 1988 to a peak of 55.0% in 1989. The average harvest rate estimate for the Alaska troll fishery by stock was 47.5% for the Berners River, 52.3% for Ford Arm Lake, and 36.4% for Hugh Smith Lake. The average for all stocks and all years was 44.9%. Harvest rates by all gear types combined varied substantially among stocks. The Berners River stock, which is taken about equally by the troll fishery and the Lynn Canal drift gillnet fishery, was harvested at an estimated average rate of 75.3% (range 61.9-92.9%). The Ford Arm Lake stock was harvested primarily by the troll fishery at an estimated average rate of 55.8% (range 43.6-69.1%). The Hugh Smith Lake stock was harvested by several fisheries at an estimated average combined rate of 66.2%; the 1982-88 average rate of 61.8% (range 52.3-66.5%) increased to 82.1% in 1989 and to 81.1% in 1990. Juvenile coho salmon tagged in the Berners River in late June of 1980 to 1989 survived to adult return, as determined by catch and escapement, at an estimated average rate of 5.3% (range 2.9-8.8%). Similarly, Ford Arm Lake juveniles tagged in July and August survived at an estimated average rate of 9.5% (range 6.0-14.4%), and smolts that migrated from Hugh Smith Lake survived at an estimated average rate of 10.7% (range 4.2-19.1%). Smolts that migrated from the Berners River in 1989 survived at an estimated rate of 19.8%. At Hugh Smith Lake, 5 years of age-.1 coho salmon escapements ranging from 903 to 2,144 produced a narrow range of estimated smolt emigrations (23,480-29,548); no relationship between escapement and smolt production was evident. Recent results continue to support earlier conclusions about the relative stability of coho production from some lake systems and the important effect of marine survival rates on adult production. Determination of spawner-recruit relationships for the Hugh Smith Lake stock and the other indicator stocks was not possible.Full Article (PDF 241 kB)
A Model to Predict Pacific Herring Age Composition in Early and Late Spawning Migrations in Kamishak Bay, Alaska
Henry J. Yuen - Vol. 1(1):35-54. 1994.
Observations of a mid-April spawning migration of older-aged Pacific herring Clupea pallasi in Kamishak Bay, Alaska, followed by a younger-aged herring spawning migration in May was supported with a two-sided, two-sample Smirnov test. When a shift in age composition occurred, those in mid-May reflected an influx of age-3 and older herring, whereas late April transitions were due to increased numbers of age-4 and older herring. A model was developed to predict a composite age composition from the early age composition for those years when late age composition samples are absent and the following-year age composition indicates an unexplained recruitment of age-4 herring. The model does not use survival rates and is independent of forecast models.Full Article (PDF 316 kB)
Reducing the Size Limit on Alaska Red King Crab: Price and Revenue Implications
Sarah A. Bibb and Scott C. Matulich - Vol. 1(1):55-65. 1994.
A size-structured shellfish population, like Alaska king crab Paralithodes camtschaticus poses special challenges for fishery managers and industry, alike. One often overlooked issue centers on how the size structure of the catch translates into prices and industry revenues. This investigation provides preliminary insight into wholesale price determination for frozen red king crab legs and claws, which are sold by size in the U.S. wholesale market. Bayesian bootstrapping with informative priors was used to estimate the pricing model. Two policy simulations were conducted to assess how a lower size limit might have affected wholesale prices during the 1987-88 and 1988-89 marketing years. The results show that prices-by-size can change substantially and processor revenues can rise slightly or fall depending upon how management policies affect the size structure of the catch.Full Article (PDF 75 kB)
A Bayesian Approach for Estimating Hatchery Contribution in a Series of Salmon Fisheries
Harold J. Geiger - Vol. 1(1):66-75. 1994.
Bayesian methods provide an under-appreciated way of analyzing tag or mark data for hatchery salmon stock identification. For example, the otolith bones can now be marked in captive juvenile salmon, these marks remaining visible in the returning adults. Fishery managers can summarize what is known and unknown about the underlying proportion of hatchery fish in these fisheries using Bayesian methods and the beta probability distribution. Close examination of Bayesian probability theory exposes a philosophy in close agreement with common sense and a form of inference that is direct and agrees with the way people use the notion of probability in everyday, colloquial speech. This theory also provides a straightforward means to allocate sampling resources, in a staged manner, based on information obtained from initial sampling.Full Article (PDF 87 kB)
Pacific Salmon Management - The View from Alaska
Charles P. Meacham and John H. Clark - Vol. 1(1):76-80. 1994. No Abstract.Full Article (PDF 93 kB)
Results of a Questionnaire on Research and Management Priorities for Commercial Crab Species in Alaska
Margaret C. Murphy, William E. Donaldson, and Jie Zheng - Vol.1(1):81-96. 1994.
A questionnaire was sent to the majority of researchers involved with Alaska shellfish to identify crab research and management priorities. Subjects and commercially exploited crab species were prioritized using a weighted rank frequency. The highest priority research need was assessment of handling/gear mortality in pot and trawl fisheries followed by evaluation of alternative stock assessment methods. Research targeting red king crabs Paralithodes camtschaticus was highest species priority among respondents, followed by golden king crabs Lithodes aequispina, Tanner crabs Chionoecetes bairdi, and snow crabs c. opilio.Full Article (PDF 76 kB)
Detection of Ceratomyxa shasta in Alaskan Chum Salmon, Oncorhynchus keta
Jill E. Follett, Jana L. Geesin, and Tamara M. Burton - Vol. 1(1):97-98. 1994. No Abstract.Full Article (PDF 33 kB)
AFRB: A Research Step Toward Better Management
Carl L. Rosier - Vol. 1(1):99. 1994.
(No Abstract) Full Editorial:
When Alaska became a state in 1959, the new state government assumed responsibility for managing most of its fishery resources. At that time, many of the resources had been depleted following an extended history of overharvest. As the new Department of Fish and Game gained regulatory authority and grassroots public support for conservation grew, salmon fisheries began to prosper. The application of limited entry and hatchery technology coupled with increasing control of foreign high seas fisheries in the early 1970s provided fishermen with an economic incentive to support long-term conservation of our fisheries. Databases from the fisheries were gradually assembled, and research was carefully targeted to the needs of management and fisheries development.
Because management jurisdiction of Alaska's fisheries is now more widely integrated with a spectrum of federal and state agencies, interagency heterosis has sponsored increasingly higher standards for research. We need to continue to investigate and accumulate knowledge on population dynamics, ecological relationships, economics, genetics, aquaculture, etc. As oil wealth predictably plummets, expansion of our economy from renewable resources - in particular our fisheries - must be the direction of the future. Only through increasing our emphasis on research and demanding higher standards will we improve management and achieve these goals.
In keeping with these high standards, the research we do must develop strong credibility among our sister agencies, which means it must be validated and authenticated through established scientific peer-review protocols and become part of the formal literature. Grey literature, while still essential for reporting and archiving much or our routine data-collection activities, can no longer be the vehicle to deliver research findings.
An important charge for our research staff is to critically examine the collective data from our past management history and to consolidate and analyze these extensive data sets to ensure continual and timely refinement of our management policies. Only by periodically and critically examining what we have done, can we hope to improve where we are going.
This first issue of the Alaska Fisheries Research Bulletin (AFRB) has evolved from our old monograph series, the Fishery Research Bulletin. This transition to a more streamlined and cost-effective way of doing business was carried over into the AFRB, which represents a more consolidated approach to reporting than its predecessor.
We see this journal reaching researchers from the global community, and we are therefore expanding our editorial board and our peer referees to include a broader range of expertise outside state government. I encourage contributions from staff within the Department of Fish and Game, and I want to personally encourage our staff to dedicate the necessary time and resources to publish your findings. To ensure the broadest perspective on solutions to Alaska's fishery problems, we are pleased to open AFRB to external authors as well. While reflecting the department's commitment to publishing its research in the formal literature, AFRB was primarily created to serve those who may both benefit from and contribute to research that is conveniently aggregated in one journal focusing on the management and development of Alaska's vast fisheries.
The Challenges of Change
Jeffery P. Koenings - Vol. 1(1):99-100. 1994.
(No Abstract) Full Editorial:
It is well known that most organizations are resistant to change, yet challenges brought on by change enable an organization to reinvent itself. Therein lies a challenge in and of itself. The purpose of change is to respond to external and internal needs in a manner that enables the organization to evolve. The Department of Fish and Game has and continues to undergo structural modifications in response to major budget cuts and to the changing values of the fisheries it manages.
Alaska is known as the "Saudi Arabia" of fisheries management; in other words, our fish and shellfish stocks are generally healthy and providing sustainable yields. Nearly 60% of the seafood harvested in the United States is of Alaskan origin. The department's management and research programs have provided all-time record harvests of salmon, the highest of which recently approached just under 200 million fish.
At the same time, the large volume of farmed fish appearing on the international market over the last decade now exceeds Alaska's entire supply. This has reduced fish prices and renewed pressure to reduce the overall size of Alaska's fishing fleets. A need to increase the volume of fish harvested and to compensate for lower prices has put tremendous pressure on managers to harvest all of the yields available. This, in turn, puts far too much pressure on our stocks.
The state's fisheries are also facing significant challenges. Included are the effects of endangered species legislation stemming from losses of sustainable salmon populations throughout the Pacific Northwest, problems with marine mammal populations, and an overwhelming pressure from the seafood industry to enter into new fisheries involving nontraditional species, such as red and green sea urchins, sea cucumbers, and geoducks, to name a few.
Research has improved the fishery manager's ability to protect sustainable yields, to maintain stocks, and to stabilize the industry's market share in the international arena. Working with the proper and most advanced tools is especially important in light of decreasing management dollars within this agency. The results of any research effort can lose its impact if not reported in a concise, efficient manner to peers.
The department is changing the way it reports its research by substantially increasing the number of applied research articles which emphasize a synthesis of information in the format of a highly visible research bulletin. Over time, I envision the bulletin to increase in frequency and to include larger monographs.
The transfer of information from peer-reviewed research and management activities will help this department adapt its management techniques to meet these challenges. Information is useless unless peers can understand and use the results. The purpose of this publication is to rapidly distribute our results to scientists within and outside the boundaries of Alaska. I am confident that changing the scope of our research bulletin will meet the department's need. It will also promote excellence in our programs and allow us to put more focus on input from scientists carrying out research on Alaska's fishery resources.
The bottom line is that the Alaska Fishery Research Bulletin is designed to serve fisheries professionals by simplifying access to contemporary findings and by aggregating research results on Alaskan fisheries issues. Based on the health of our fisheries, it could truly become the first publication to couple management science with applied fishery research.