Alaska Fishery Research Bulletin Issues, Vol.6 No. 2 - Winter 1999

The Economic Value of Alaska's Copper River Personal Use and Subsistence Fisheries

Michelle M. Henderson, Keith R. Criddle, and S. Todd Lee - Vol. 6(2):63-69. 2000.

Commercial, sport, personal use, and subsistence fishers share the salmon harvest on the Copper River, Alaska. The allocation of salmon among these user groups is a contentious and recurring issue. Economic analyses, along with biological, legal, social, and cultural considerations, have the potential to help policy makers appreciate the consequences of alternative allocations. The zonal travel cost method is used in this study to estimate the net economic value (consumer surplus) of the Copper River basin personal use and subsistence fisheries. The nature of the fishery and the data set are especially well suited for this purpose.

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Changes in Chela Heights and Carapace Lengths in Male and Female Golden King Crabs Lithodes aequispinus after Molting in the Laboratory

A. J. Paul and J. M. Paul - Vol. 6(2):70-77. 2000.

Golden king crabs Lithodes aequispinus from Prince William Sound, Alaska were measured for changes in carapace length (CL) and chela height (CH) after they molted in the laboratory. The predicted increase in CL for males (95 to 155 mm) was expressed by the equation: New CL (mm) = Initial CL (0.91) + 21.90 (r 2 = 0.97). The postmolt CH (Y) was linearly related to premolt values (X) by the equation: Y = 0.90X + 6.79 (r 2 = 0.85). Increases in CL and CH for males averaged 10% (SD = 3) and 12% (SD = 10), respectively. After molting CH/CL increased in 42%, decreased in 41%, and stayed the same in the remaining 17% of the 58 males. The predicted increase in CL for females (104 to 157 mm) was expressed by the equation: New CL (mm) = Initial CL (0.97) + 10.21 (r 2 = 0.91). Increases in CL and CH averaged 5% (SD = 2) and 16% (SD = 18), respectively, for ovigerous females. Like males claw growth in millimeters in females was weakly dependent on initial CH. After molting CH/CL ratios increased in 48%, decreased in 14%, and stayed the same in 38% of 104 females.

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Northern Range Extensions and Habitat Observations for Blackeye Goby Rhinogobiops nicholsii and Kelp Perch Brachyistius frenatus in Southeastern Alaska

David J. Csepp and Bruce L. Wing - Vol. 6(2):78-84. 2000.

Blackeye goby Rhinogobiops nicholsii (Bean 1882) and kelp perch Brachyistius frenatus (Gill 1862) were caught or observed from April to September 1998 and 1999 with beach seines and a remotely operated vehicle at 20 locations near Sitka, Craig, and Klawock in southeastern Alaska. This is the first verified account of blackeye goby (Gobiidae) and kelp perch (Embiotocidae) in Alaska. We captured blackeye gobies as far north as lat 57°17'26"N, long 135°35'14"W, near Sitka, and kelp perch at lat 55°34'38"N, long 133°05'42"W, near Klawock; these may be the northern range limits for these species. Blackeye gobies were found in greater ranges of temperature (9.5° to 17.0°C) and salinity (13 to 27 on the Practical Salinity Scale) than kelp perch (10.0° to 13.2°C, salinity 22 to 28). Specimens of both species have been deposited and cataloged in the Auke Bay Laboratory fish collection.

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Prevalence of the Sockeye Salmon Brain Parasite Myxobolus arcticus in Selected Alaska Streams

Adam Moles and Kathleen Jensen - Vol. 6(2):85-93. 2000.

Over 10,000 spawning sockeye salmon Oncorhynchus nerka throughout Alaska were examined for the presence of the brain parasite Myxobolus arcticus to evaluate its potential as a natural marker to separate mixed stock fisheries in Alaska. Prevalence of the parasite (proportion of fish infected by the parasite) differed widely among sampling locations. The brain parasite, previously reported as common in southeastern Alaska, infected sockeye salmon primarily in coastal lake systems of eastern Prince William Sound and the Copper River area. Brain parasites were present in >85% of the fish returning to lakes east of Cook Inlet, whereas <20% of fish returning to glacial and riverine habitats in the same region were infected. Sockeye salmon systems west of Prince William Sound, such as Bristol Bay and Cook Inlet, were largely devoid of the parasite. Prevalence of the parasite in southeastern Alaska systems appeared stable over the last decade in lake systems but was more variable in riverine habitat. In the Taku River parasite prevalence varied widely between sites but was similar among years for most locations within the river. The restricted geographic distribution and potential for low interannual variability suggest that M. arcticus could serve, especially when used in conjunction with other techniques, as an effective biological marker for estimating origins of sockeye salmon caught in high seas and coastal fisheries.

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Capture Efficiency and Size Selectivity of Two Types of Pots for Red King Crabs in the Bering Sea

Shijie Zhou and Gordon H. Kruse - Vol. 6(2):94-103. 2000.

We compared the catch efficiency and size selectivity of experimental and standard king crab pots in Bristol Bay in the eastern Bering Sea in 1996. The experimental pot was intended to selectively catch legal-sized (carapace width greater than or equal to 165 mm) male red king crabs and reduce the catch of smaller (< 165 mm) crabs. Mean catch per pot haul (CPUE) for legal male red king crabs was 25.3 (SD = 7.9) for standard pots and 20.5 (SD = 8.5) for experimental pots. Mean CPUE of all crabs combined was 63.3 (SD = 26.0) for standard pots and 55.0 (SD = 28.1) for experimental pots. We found no statistically significant differences in CPUE (P > 0.05) except standard pots caught significantly more crabs greater than or equal to 130 mm carapace length in 3 of 6 fishing locations than experimental pots. When CPUE was standardized by effective pot volume, the experimental pots had significantly higher catch per unit of volume for all crab groups than the standard pots. Female and small male crabs remained in both pots during the 2-d soak time even though they were capable of leaving.

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Food Consumption and Growth of Juvenile Arrowtooth Flounders

A. J. Paul, J. M. Paul, R. L. Smith, and K. A. Bouwens - Vol. 6(2):104-107. 2000.

Food consumption and growth of juvenile arrowtooth flounders Atheresthes stomias were examined in the laboratory. Weight gain, Y (in % BW/d) was related linearly to food consumption, X (in J/g/d): Y = 0.0033X - 0.0564; r 2 = 0.75 at 4°C. Fish 30 to 300 g had similar energy conversion efficiencies. When fed Pacific herring Clupea pallasi at 4°C, maintenance ration was estimated to be 17 J/g/d. Minimum estimates for daily ration to achieve growth rates observed in the Gulf of Alaska were approximately 3.0 to 1.0% BW/d for 1- to 4-year-old arrowtooth flounders, respectively, when fed walleye pollock Theragra chalcogramma. When feeding on euphausiids, the corresponding consumption rates were 6.9 and 2.4% BW/d.

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