Podding Behavior of Adult King Crab and Its Effect on Abundance-Estimate Precision

Podding Behavior of Adult King Crab and Its Effect on Abundance-Estimate Precision

C.B. Dew

Podding Behavior of Adult King Crab and Its Effect on Abundance-Estimate PrecisionThis is part of Biology and Management of Exploited Crab Populations under Climate Change
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Description

The Alaska red king crab, Paralithodes camtschaticus, is a major target of the Bristol Bay stock assessment bottom-trawl survey conducted annually by the U.S. National Marine Fisheries Service. Because of the difficulty of sampling extremely patchy spatial distributions, it is important to know whether the podding behavior documented for juvenile red king crab continues into adulthood. A common assumption is that adults are not podding crab. I present data from in situ investigations at Kodiak and adaptive cluster sampling in Bristol Bay, which demonstrates that adults are podding crab whose behavior results in discrete aggregations that can cover more than 370 km2. Because of this behavior, and because historical estimates of precision were based on a flawed method (post-stratification), the uncertainty of annual abundance estimates, and their association with climate changes, is greater than previously thought.

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