MEPS 547:211-217 (2016)  -  DOI: https://doi.org/10.3354/meps11625

ABSTRACT: In fishes, strong year classes can suppress survival of the following year class because of interactions such as cannibalism and between-cohort competition. The incidence of such negative intra-specific interactions in recruitment dynamics was investigated for commercially relevant fish stocks in the Atlantic Ocean using residuals from the Ricker stock-recruitment model. The autocorrelation of recruitment residuals at lags ranging from 1 to 5 yr were computed and examined. The number of stocks that exhibited positive autocorrelation in recruitment residuals decreased with increased lag length. Negative autocorrelation of recruitment residuals at lags were found in a number of stocks from 3 to 5 yr and were interpreted as evidence of cannibalism or intra-specific competition. Autocorrelation analysis of recruitment time-series provides an easy and generally accessible method of detecting negative intra-specific interactions. However, it is a conservative method, especially when stocks have undergone periods of low abundance or are subject to other strong density-dependent or -independent influences. While the majority of stocks studied here did not exhibit evidence for negative intra-specific interactions, our findings nonetheless suggest that cannibalism and competition at high stock levels can have important consequences on the determination of sustainable biomass and harvest levels.

KEY WORDS: Cannibalism · Intra-specific competition · Recruitment · Population dynamics · Atlantic Ocean