Developing a Research and Restoration Plan for Arctic-Yukon-Kuskokwim (Western Alaska) Salmon (2005) / Chapter Skim
Currently Skimming:
2 Salmon Life History and Background
2 Salmon Life History and Background
Pages 23-37
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From page 23... ...
site visits showed that there is a substantial body of traditional knowledge about salmon life history in the AYK region that has yet to be integrated with information from the published scientific literature. Much of the information in this chapter is summarized from more detailed reviews by Burgner (1991)
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From page 24... ...
Additional sources of information are cited throughout the text. General Life History Characteristics The life histories of all five species of Pacific salmon found in the AYK region share several general characteristics.
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From page 25... ...
These changes prepare them for their downstream migration and for entering the marine environment. The other three species -- sockeye, coho, and Chinook salmon -- will spend 1 or 2 years rearing in freshwater and reach a larger size (8-20 g, 70-150 mm)
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From page 26... ...
In general, western Alaskan stocks migrate farther offshore in winter than stocks from more southerly regions of North America. Based on the distribution of age 0.1 salmon the following spring, many or most AYK juvenile sockeye, chum, pink, and coho salmon move south through the Aleutian passes into the central and eastern North Pacific Ocean in late fall or
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From page 27... ...
Interspecific patterns of upstream migrations are similar across the AYK region, with Chinook salmon entering rivers first, followed by summer chum and pink salmon, and with fall chum and coho salmon entering last. Knudsen (2003)
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From page 28... ...
. Historical INPFC/NPAFC data on the distribution of age 0.1 fish the following spring suggest that many or most AYK pink salmon move south through the Aleutian passes into the central and eastern North Pacific Ocean in late fall or winter.
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From page 29... ...
OCC surveys in neritic habitats over the eastern Bering Sea shelf and Kotzebue Sound show that juvenile AYK chum salmon are generally north of 58°N in the fall. Based on the distribution of age 0.1 fish the following spring, many or most of these individuals are thought to move south through the Aleutian passes into the central and eastern North Pacific Ocean in late fall and winter.
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From page 30... ...
By January and early February relatively few juvenile sockeye salmon remain in the Bering Sea, and they are broadly distributed across the central and eastern North Pacific Ocean. Their winter high-seas distribution in the North Pacific extends southward to about 46°N in the central North Pacific and 4851°N south of the Alaska Peninsula.
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From page 31... ...
OCC surveys over the eastern Bering Sea shelf and Kotzebue Sound found juveniles in nearshore habitats during fall, suggesting juvenile coho salmon spend a considerable part of their first summer near shore. During salmon research (purse seine)
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From page 32... ...
Chinook Salmon The life history of Chinook salmon in the AYK region resembles that of coho salmon in some ways, but they are distinguished by their longer marine residence and larger body size. With few exceptions, AYK juvenile Chinook salmon smolts are stream-type (predominantly freshwater age 1.)
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From page 33... ...
OCC juvenile salmon surveys over the eastern Bering Sea shelf and Kotzebue Sound reveal that juvenile Chinook salmon occur in nearshore marine habitats during fall, suggesting that they do not all move offshore as soon as they enter the marine environment. Traditional ecological knowledge also reveals that Norton Sound is a rearing area for Yukon River Chinook salmon juveniles in summer and fall.
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From page 34... ...
Conversely, small body size and drab coloration has evolved in sockeye salmon stocks that spawn in shallow streams subject to heavy predation by bears. Similar local adaptations of other life history traits undoubtedly exist, including characteristics such as egg size, fecundity, developmental rates, foraging and predator avoidance behavior, length of freshwater and marine residence, migratory timing, migratory routes, and reproductive behavior.
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From page 35... ...
The declines in the past 15 years are at least somewhat reflective of declines in run sizes. Figures 2-2 and 2-3 present information on gross earnings from commercial fishing in the Yukon-Koyukuk and the Wade Hampton census areas.
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From page 36... ...
Those losses are progressively harder to reverse with time. FIGURE 2-2 Gross earnings from commercial fishing in the Yukon-Koyukuk census area.
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From page 37... ...
SALMON LIFE HISTORY AND BACKGROUND 37 FIGURE 2-3 Gross earnings from commercial fishing in the Wade Hampton census area. Source: Alaska Commercial Fisheries Entry Commission 2004.
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