Growth of Norway lobster, Nephrops norvegicus (Linnaeus 1758), in the Skagerrak, estimated from tagging experiments and length frequency data

Parameter values for the von Bertalanffy growth model are estimated for Nephrops norvegicus in the Skagerrak on the Swedish west coast using analysis of length frequency distribution from commercial catches and tag-recapture data.

The asymptotic lengths (L) for males and females are estimated from size distributions using a modified Powell-Wetherall plot. The tagging experiment was conducted with Floy streamer tag and analysed in a "forced" Gulland-Holt plot to estimate the growth coefficient K for males. The estimates of L (72.9) and K (0.138) for males differ from those currently used in the ICES assessment for this area (76 and 0.16, respectively), and the results are discussed in relation to sensitivity to reference points from analytical stock assessments and possible implications for management decisions.