Towards predicting recruitment success of anchovy Engrauus capensis Gilchrist in the Southern Benguela system using environmental variables: A rule-based model

Abstract

The construction of a rule-based model aimed at assisting in the management of the Cape anchovy Engraulis capensis by predicting the success of recruitment is described. of the many environmental variables which, potentially, may give an indication of future recruitment, the fundamental physical indices of sea surface temperature and wind were selected for inclusion in the model. From simple regression and correlation analysis, qualitative rules were constructed relating recruitment success to wind frequency, wind velocity and sea surface temperature in one or more of the spawning, transport and recruitment (nursery) areas of the anchovy. By calibration of the rules, and the consideration of annual spawner biomass, it was possible to obtain a good estimate of observed recruitment. The model was then used to examine the implications of a number of possible environmental scenarios on annual recruitment. Results from the statistical analyses and those from the model indicate that transport of larvae may be one of the dominant components of the Benguela system that affects anchovy recruitment. Furthermore, simulated recruitment emphasizes the high within-season variation in recruitment. © 1994 Taylor & Francis Group, LLC.