Synchrony in the recruitment time-series of plaice (Pleuronectes platessa L) around the United Kingdom and the influence of sea temperature

Historical time-series of recruitment to plaice stocks around the United Ki ngdom were examined for evidence of synchrony. Correlations were significan t for most pair-wise comparisons and a mete-analysis test over all the stoc ks was highly significant. Previous studies on plaice recruitment in the No rth Sea have suggested that a negative relationship exists between sea temp erature, during the first few months of the year, and subsequent year-class strength. When we examined the correlations between sea surface temperatur e and plaice recruitment, we found statistically significant negative relat ionships for most areas. These were strongest for the period February-June. Our results are consistent with the hypothesis that the temperature effect on recruitment of North Sea plaice is due to changes in predation pressure on the planktonic stages. However, western (North Sea and Channel) and eas tern (Irish Sea and Celtic Sea) stocks appeared to respond to different tim e-scales of temperature variability which may imply that different mechanis ms could be operating in these stocks. Management of plaice is based upon projections of future stock dynamics. Co mpared with fisheries on some other species, those on plaice are less depen dent on the in-coming year-class. Therefore, the incorporation of sea tempe rature data into plaice stock dynamic models will probably not have a large impact on short-term projections. However, incorporation of a temperature relationship will allow medium to long-term forecasts to be made under vary ing environmental scenarios. These may provide a more realistic range of pr ojections of future stock trends than is currently achieved. Crown Copyrigh t (C) 2000 Published by Elsevier Science B.V. All rights reserved.