Publication Abstract

Synchrony in the recruitment time-series of plaice (Pleuronectes platessa) around the UK and the influence of sea temperatures

Synchrony in the recruitment time-series of plaice (Pleuronectes platessa) around the UK and the influence of sea temperatures

C.J. Fox, B.P. Planque and C.D. Darby

Historical time-series of recruitment to plaice stocks around the United Kingdom were examined for evidence of synchrony. Our results reject the null hypothesis (no synchrony) for most stock-pairs and are highly significant using a meta-analysis test over all the stocks. Synchrony between stocks might arise through population exchange or be due to a large-scale forcing operating over the whole region. Population exchange between adjacent stocks is likely to occur but there is no evidence that more widely separated stocks (such as North Sea and Irish Sea) are linked in this manner. Previous studies on plaice recruitment in the North Sea have suggested that a negative relationship exists between sea temperature, during the first few months of the year, and subsequent year-class strength. Although the average sea surface temperature for areas corresponding to the different plaice stocks varies, the pattern in inter-annual temperature fluctuations is similar. Temperature anomalies may therefore affect a region considerably larger than the southern North Sea. When we examined the correlations between sea surface temperature and plaice recruitment, we found statistically significant negative relationships for all areas. Our results are consistent with the hypothesis that the underlying mechanism is due to reduced predation pressure on plaice eggs in cold years. This could be due either to lower predator abundance or to reduced consumption rates.

Because the fisheries on plaice stocks are not as dependent on the in-coming yearclass as some other stocks, incorporation of sea temperature data into plaice stock dynamic models will probably not have a large impact on short-term projections. However, it may allow medium to long-term management forecasts to be made under varying environmental scenarios.

Reference:

C.J. Fox, B.P. Planque and C.D. Darby, 2000. Synchrony in the recruitment time-series of plaice (Pleuronectes platessa) around the UK and the influence of sea temperatures. Journal of Sea Research, 44(1-2): 159-168

C.J. Fox*, B.P. Planque* and C.D. Darby*

Journal of Sea Research, 44(1-2): 159-168