Population assessment using a length-based population analysis for the Japanese hair crab (Erimacrus isenbeckii)

Population assessment using a length-based population analysis for the Japanese hair crab (Erimacrus isenbeckii)

H. Yamaguchi, Y. Ueda, Y. Kanno, and T. Matsuishi

Population assessment using a length-based population analysis for the Japanese hair crab (Erimacrus isenbeckii)This is part of Crabs in Cold Water Regions: Biology, Management, and Economics
PDF    
To download the free PDF [288.4 KB], please enter:
-or-

Description

The purpose of this paper is to apply an improved length-based population analysis (LPA) to eastern Hokkaido hair crab, Erimacrus isenbeckii. The model incorporates stochastic growth and a gradual recruitment over length. The model contains a nonlinear least squares method to estimate growth, probability of molting, abundance, and recruitment. Abundance and catch data from 1992 to 1999 were used to test the model. The population abundances estimated by LPA fit the observed abundances well. Estimated abundance and recruitment showed that the hair crab population in eastern Hokkaido was strongly influenced by yearly recruitment. A large abundance was the result of an abundant recruitment. This may be caused by the unsettled condition of the hair crab population in eastern Hokkaido. The estimated molt frequency by length differed from those previously reported, suggesting that some new-shelled crabs may molt. We suggest three more terms to improve the model.

Item details