Preliminary assessment of a direct agedetermination method for 3 commercially important crustaceans from Alaska

Abstract

Management of commercially important crab and shrimp species in Alaska has been hindered by the inability to directly determine the age of individual animals. We investigated the applicability of a recently developed method of age determination to red king crab (Paralithodes camtschaticus), southern Tanner crab (Chionoecetes bairdi), and spot shrimp (Pandalus platyceros) from Alaska. The cuticle structures of the mesocardiac ossicles of crabs and the eyestalks of spot shrimp were visualized with histological staining to identify the endocuticle, where growth bands have been observed in other crustaceans. For all species, paired light and dark bands were observed in longitudinal, thin sections of these structures in the majority of specimens examined. The proximal portion of the mesocardiac ossicle, where growth bands were observed, was absent in the foregut exuviae of red king and southern Tanner crabs that molted in captivity. If validated, counts of growth bands hold promise as a reliable measure for determining age of these species.