Change in maximum body size for male and female red king crab in Norwegian waters

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The harvest of the introduced and now commercially valuable red king crab (Paralithodes camtschaticus) in northern Norway has a fishery history going back to 1994. The fishery management has undergone several changes, harvest rate being very low and increasing to very high in the recent 5-10 years. A male-only fishery went on for the first 14 years and since 2008 an additional small quota on female crabs has been given, with the same minimum legal size for both sexes. In this study we investigate effects of increasing harvest rate on the maximum size of both male and female crabs and discuss possible ecological consequences. Varangerfjorden was chosen as a main study area since this is the area of longest fishery history in Norwegian waters, and has been through all stages of the management of the crab fishery. Both the mature male and the ovigerous female part of the stock displayed a reduced maximum size around 1999-2000. A new and significant reduction in maximum size occurs in accordance with the onset of a fishery quota on females in 2008. Recently maximum body size for both male and female crabs seems to have stabilized and adjusted in accordance with the present harvest rate.