Trends in age-at-recruitment and juvenile growth of cuttlefish, Sepia officinalis, from the English Channel

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The cuttlefish Sepia officinalis is a major fishery resource in the English Channel, and amongst the largest cephalopod stocks in the Northeast Atlantic. Cuttlefish live for approximately 2 years, and consequently landings depend highly upon recruitment success. In this study, we analyze early life stages for differences in age-at-recruitment and juvenile growth. Biological samples of recruits were collected monthly during 2000, 2001 and 2002, and samples of pre-recruits in 2000 and 2002, from the coastal waters of the UK and France. Age in days was determined by statolith analysis. Significant differences in age-at-recruitment were found between the autumnal recruitment, and the rest of the year, and between cohorts. Juvenile growth models were fitted for pre-recruit specimens, and indicated growth rate was significantly higher in 2002 than in 2000. Spatial differences observed were found in 2000, and indicated pre-recruit growth may depend on local environmental conditions. The results indicate that life-history is likely to be heterogeneous within the English Channel stock.