The introduced species red king crab (Paralithodes camtschaticus) in the Barents Sea: II. Growth increments and moulting probability

Russian scientists introduced the red king crab (Paralithodes camtschaticus) to the Barents Sea during the 1960s and 1970s, and the crab has now become abundant in the coastal waters of Finnmark, North Norway. The growing stock size of this introduced species raises increasing demands for management of the stock. Therefore, basic knowledge of general biology and ecology is required. This paper presents analyses of the moulting increment and moulting frequency results based on tag and recapture experiments. The mean increments in carapace length per moult of males (immature and mature) are estimated to be 17.0 mm for all premoult carapace lengths between 67 and 172 mm, while the increment decreased from 14.4 to 5.1 mm for females as they became ovigerous. The results show that the growth increments of the red king crab in Varanger are within the ranges reported in the eastern Bering Sea. A model relating probability of moulting as a function of carapace length is developed based on tag-recapture and qualitative carapace age judgement.