The role of temperature and cannibalism in interannual recruitment variation of bass in British waters

Between-year variation in bass Dicentrarchus labrax year-class strength in southern British waters is investigated. Mean spring-summer seawater temperature in the year of birth was significantly positively correlated with both the level of summer recruitment of the 0+ group to the estuarine nurseries and subsequent recruitment of IIl+ fish to the adult population. Spectral analysis of the temperature-compensated time series showed that a statistically significant proportion of the variation not attributable to temperature was periodic at 0.33 cycles year(-1). Therefore, a simple, three-parameter model, combining a linear relationship between temperature and abundance and a second-order autoregressive model can be used to describe and predict variation in relative adult YCS. Bass remain for their first 3 years within their estuarine nursery areas. As I+ fish were observed in Southampton water to cannibalize the 0+ group, it is suggested that strong year-classes suppress recruitment for the next 2 years even if the temperature is suitable to promote a strong year-class. Cyclic variation in recruitment caused by intraspecific interactions, particularly cannibalism, may be a feature of other marine fish that use estuaries as nursery areas. (C) 1997 The Fisheries Society of the British Isles.