Intertidal Fishery of the Patagonian Red Octopus, Enteroctopus megalocyathus (Gould 1852): Reproductive Status and Catch Composition in the North of San Jorge Gulf (Patagonian Atlantic Coast)

Abstract

Enteroctopus megalocyathus is one of the most important octopus fishing resource in Patagonian Atlantic and Patagonian Pacific coasts, but there is no information available regarding the biological aspects of the species in intertidal environments. In this work, maturity condition of E. megalocyathus and composition of the capture obtained by a small-scale fishery on intertidal rocky shores in the north of San Jorge Gulf (Patagonian Atlantic coast) were investigated, together with the fishing capacity of the fishermen that operate in the area. Throughout each of the three fishing seasons analyzed, a progressive increase in sexual maturity stages was observed for both sexes. Mature-spawning and spent females were not registered in the catches, while mature males constituted only 7.5% of the total catches. Females resulted heavier than males at a given mantle length. Weight-composition of catches revealed the presence of middle weight animals in all fishing months and an increase of mean weights along the fishing season. Towards the end of the fishing period, the proportion of mature males increased and females outnumbered males. At that time, lighter and immature octopuses recruited to fishing areas, mean weight of the catches decreased and most fishermen stopped fishing. Mean individual catch was 18.1 kg/fisherman-day, but it was highly variable. Results suggest that females reach maturity, become able to copulate, and spawn in the following months away from fishing grounds, while the reproductive stock remains little affected.