Handline catches and stock identity of snoek Thyrsites atun off South Africa and Namibia

Abstract

Handline catches of snoek Thyrsites atun off southern Africa tend to be of sexually mature fish, and to be either good off South Africa or off Namibia but not in both localities simultaneously. When catches are low off Namibia they are made mostly in the south, suggesting a southward displacement of the stock, and vice versa. Handline catches made off South Africa, mainly in winter, are significantly negatively correlated with those made off Namibia the preceding summer, in agreement with this hypothesis. That the converse does not apply is attributed to recruitment of maturing fish to the spawning shoals as the latter leave South African waters. Although some immature snoek are probably resident in South African waters throughout the year, snoek in the South-East Atlantic are thought to belong to a single stock. © 1990 Taylor and Francis Group, LLC.