Variation in Size at Maturity of Tanner Crab in Southeastern Alaska, U.S.A.

Variation in Size at Maturity of Tanner Crab in Southeastern Alaska, U.S.A.

C.E. Siddon and J.A. Bednarski

Variation in Size at Maturity of Tanner Crab in Southeastern Alaska, U.S.A.This is part of Biology and Management of Exploited Crab Populations under Climate Change
PDF    
To download the free PDF [467.4 KB], please enter:
-or-

Description

Predicting climate change effects on commercially important species is an increasingly important issue for fisheries scientists. It requires understanding how climate change will affect oceanographic conditions and how this will influence population dynamics of target species. Utilizing natural experiments where oceanographic conditions change over small spatial scales is one way to examine the role of climate change. We examine the variability of the size at maturity for Tanner crab (Chionoecetes bairdi) in the fjord system of southeastern Alaska. Variation in size at maturity for male and female crabs was examined among six survey areas and compared with changes in latitude, depth, temperature, temperature fluctuations, and fishing pressure.

The size at maturity varied significantly among areas for both male and female Tanner crabs, but they were not correlated. Male size at maturity averaged 117 mm carapace width (CW) and ranged from 108 mm in Glacier Bay to 135 mm in Stephens Passage. Female size at maturity averaged 89 mm CW, with a minimum in Glacier Bay (85 mm) and a maximum in Port Camden (95 mm). Average water temperatures ranged from 5.5ºC in Holkham Bay to 7.7ºC in Port Camden. Temperature fluctuations varied substantially, with almost no change in water temperatures in Holkham Bay and Port Camden, and temperature drops of 1ºC in 1 hour in Icy Strait. No environmental or fishing pressure variables explained variations in size at maturity; this suggests other biological factors may play a greater role in determining size at maturity for Tanner crab in southeastern Alaska.

Item details