THE ROLE OF TEMPERATURE AND CANNIBALISM IN INTERANNUAL RECRUITMENT VARIATION OF BASS IN BRITISH WATERS

Between-year variation in bass Dicentrarchus labrax year-class strengt h in southern British waters is investigated. Mean spring-summer seawa ter temperature in the year of birth was significantly positively corr elated with both the level of summer recruitment of the 0+ group to th e estuarine nurseries and subsequent recruitment of IIl+ fish to the a dult population. Spectral analysis of the temperature-compensated time series showed that a statistically significant proportion of the vari ation not attributable to temperature was periodic at 0.33 cycles year (-1). Therefore, a simple, three-parameter model, combining a linear r elationship between temperature and abundance and a second-order autor egressive model can be used to describe and predict variation in relat ive adult YCS. Bass remain for their first 3 years within their estuar ine nursery areas. As I+ fish were observed in Southampton water to ca nnibalize the 0+ group, it is suggested that strong year-classes suppr ess recruitment for the next 2 years even if the temperature is suitab le to promote a strong year-class. Cyclic variation in recruitment cau sed 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.