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Transactions of The American Fisheries Society | 1995

Retention of Jet-Injected Marks on Juvenile Coho and Sockeye Salmon

John F. Thedinga; Scott W. Johnson

Abstract Juvenile coho salmon Oncorhynchus kisutch and sockeye salmon O. nerka were marked by jet injection to determine mark retention of three substances: Alcian Blue dye, black india ink, and acrylic paint (red, fluorescent yellow, and fluorescent orange). Fish were marked on the caudal fin and then held for 40 weeks in flow-through freshwater tanks. Coho and sockeye salmon both retained Alcian Blue and fluorescent orange marks best. The highest mark retention after 40 weeks was 73% for Alcian Blue marks on sockeye salmon. Overall mark retention was greater for orange-, yellow-, and black-marked coho salmon than for similarly marked sockeye salmon. Differences in growth rate—sockeye salmon grew about 7 mm more than coho salmon—probably contributed to the differences in mark retention between species. All colors appear suitable for short-term ( 6 weeks) marks, we recommend Alcian Blue dye or fluorescent orange or yellow acrylic paint for coho salmon and Alcian Blue dye fo...


Northwest Science | 2010

Fish Assemblages in Nearshore Habitats of Prince William Sound, Alaska

Scott W. Johnson; John F. Thedinga; A. Darcie Neff; Patricia M. Harris; Mandy R. Lindeberg; Jacek M. Maselko; Stanley D. Rice

Abstract We sampled fish at eight locations in western Prince William Sound (PWS), Alaska, in April, July, and September 2006, and July 2007, to identify species assemblages and habitat use. At each location, fish were sampled with a 37-m long variable mesh beach seine in three nearshore habitats: bedrock outcrops, eelgrass meadows, and cobble beaches with kelp. A total of 49,060 fish representing 45 species were captured in 95 beach seine hauls. Catch-per-unit-effort (CPUE, all species) did not differ by season but did differ by habitat type—CPUE was greater in eelgrass and kelp than in bedrock. Seasonal pulses in catch were evident for some species; pink salmon were captured only in spring and summer, Pacific herring only in summer and fall, and capelin only in fall. Species richness was greater in summer (34) than in spring (23) or fall (28), and greater in eelgrass (34) than in bedrock (22) or kelp (33). Species that were good discriminators among seasonal collections were pink salmon, saffron cod, crescent gunnel, and Pacific herring, whereas species that were good discriminators among habitat collections were crescent gunnel, tubesnout, bay pipefish, saffron cod, and Arctic shanny. Of the most abundant species captured, most were juveniles based on estimated size at maturity. The summer fish assemblage in western PWS has changed over the last 20 years, especially with the appearance in large numbers of saffron cod. Sites in this study can be monitored periodically to track future changes in fish assemblages and habitat that may result from local and regional human disturbance.


Transactions of The American Fisheries Society | 2008

Fish Assemblages in Shallow, Nearshore Habitats of the Bering Sea

John F. Thedinga; Scott W. Johnson; A. Darcie Neff; Mandy R. Lindeberg

Abstract The Bering Sea provides over one-half of U.S. fishery production, yet knowledge of the use of its shallow (<5 m), nearshore (<20 m from shore) waters by fish is limited. In June 2005, we sampled shallow, nearshore waters of the Bering Sea at three Aleutian islands with a beach seine to estimate the relative abundance and species distribution of fish. Three habitat types were sampled: Nonvegetated sand substrate, vegetated cobble substrate, and vegetated bedrock substrate. A total of 70 sites were seined on Akutan, Akun, and Unalaska islands. The total estimated catch was 83,910 fish representing 33 taxa. Five species comprised 98% of the total catch. Pacific sand lance Ammodytes hexapterus was the most abundant species; approximately 35,000 of these fish were captured, and they occurred in 60% of all seine hauls. The next most abundant fish were young-of-the-year (age-0) gadids (primarily walleye pollock Theragra chalcogramma), age-0 pink salmon Oncorhynchus gorbuscha, age-0 Pacific sandfish Tric...


Transactions of The American Fisheries Society | 2004

Observer Classification of Live, Mechanically Damaged, and Dead Pink Salmon Eggs

Mark G. Carls; John F. Thedinga; R. E. Thomas

Abstract The susceptibility of pink salmon Oncorhynchus gorbuscha eggs to mechanical damage (shock) was studied to test the ability of observers to discriminate among live, dead, and damaged eggs. In a series of six laboratory trials, the mean error rate in discrimination did not exceed 12% and was 3.5% or less in four of six trials. The most common error was misclassification of damaged eggs as live (≤9 ± 1% (mean ± SE)), an error that is irrelevant in field studies designed to determine the natural death rate. The second most common error was damaged eggs classified as dead (≤4.6 ± 1%) when observation times were 60 min or less; this was reduced to less than 0.5% when observations were limited to 12 min or less. Inexperienced observers were easily trained (within 1 h) to classify eggs. To accurately describe natural systems before sample disturbance, damaged and dead egg categories should not be combined when reporting data.


Environmental Biology of Fishes | 2011

Diel differences in fish assemblages in nearshore eelgrass and kelp habitats in Prince William Sound, Alaska

John F. Thedinga; Scott W. Johnson; A. Darcie Neff

The importance of a particular habitat to nearshore fishes can be best assessed by both diurnal and nocturnal sampling. To determine diel differences in fish assemblages in nearshore eelgrass and understory kelp habitats, fishes were sampled diurnally and nocturnally at six locations in western Prince William Sound, Alaska, in summer 2007. Abundance of fish between day and night were similar, but species composition and mean size of some fish changed. Species richness and species diversity were similar in eelgrass during the day and night, whereas in kelp, species richness and species diversity were greater at night than during the day. In eelgrass, saffron cod (Eleginus gracilis) was the most abundant species during the day and night. In kelp, the most abundant species were Pacific herring (Clupea pallasii) during the day and saffron cod at night. Diel differences in fish size varied by species and habitat. Mean length of saffron cod was similar between day and night in eelgrass but was greatest during the day in kelp. Pacific herring were larger at night than during the day in kelp. Diel sampling is important to identity nearshore habitats essential to fish and help manage fish stocks at risk.


Canadian Journal of Fisheries and Aquatic Sciences | 1986

Effects of Clear-cut Logging with and without Buffer Strips on juvenile Salmonids in Alaskan Streams

Michael L. Murphy; Jonathan Heifetz; Scott W. Johnson; K V. Koski; John F. Thedinga


Canadian Journal of Fisheries and Aquatic Sciences | 1989

Habitat Utilization by Juvenile Pacific Salmon (Onchorynchus) in the Glacial Taku River, Southeast Alaska

Michael L. Murphy; Jonathan Heifetz; John F. Thedinga; Scott W. Johnson; K V. Koski


North American Journal of Fisheries Management | 1994

Determination of Salmonid Smolt Yield with Rotary-Screw Traps in the Situk River, Alaska, to Predict Effects of Glacial Flooding

John F. Thedinga; Michael L. Murphy; Scott W. Johnson; J. Michael Lorenz; K V. Koski


Marine Ecology Progress Series | 2009

Steller sea lion foraging response to seasonal changes in prey availability

Michael F. Sigler; Dominic J. Tollit; Johanna J. Vollenweider; John F. Thedinga; David J. Csepp; Jamie N. Womble; Mandy Wong; Michael J. Rehberg; Andrew W. Trites


Canadian Journal of Fisheries and Aquatic Sciences | 1992

Life History of Juvenile Ocean-type Chinook Salmon (Oncorhynchus tshawytscha) in the Situk River, Alaska

Scott W. Johnson; John F. Thedinga; K V. Koski

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Scott W. Johnson

National Marine Fisheries Service

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K V. Koski

National Marine Fisheries Service

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A. Darcie Neff

National Marine Fisheries Service

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Stanley D. Rice

National Marine Fisheries Service

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Alex C. Wertheimer

National Marine Fisheries Service

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Jacek M. Maselko

National Oceanic and Atmospheric Administration

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Jonathan Heifetz

National Marine Fisheries Service

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Mandy R. Lindeberg

National Marine Fisheries Service

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Adrian G. Celewycz

National Oceanic and Atmospheric Administration

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