Enteroctopus megalocyathus, Patagonian red octopus

The Patagonian red octopus, Enteroctopus megalocyathus, is distributed around the southern end of South America, along the coasts of Chile and Argentine Patagonia, with genetically distinct populations on the Atlantic and the Pacific coasts. This chapter describes the biological and ecological aspects and evolutionary patterns of this species, based on aquaculture-related research, population biology, fishery studies, and field observations. This is a large species (up to 7kg total weight) frequently found in rocky intertidal and subtidal areas, with an estimated life span of up to 2½years, moderate fecundity, large eggs, and the largest known octopus paralarvae. Embryonic development, hatching success, hatchling performance, and feeding behaviour are strongly influenced by temperature. In particular, 16°C seems to represent an upper thermal limit for the early life stages. On the Atlantic coast, reproduction takes place during the austral summer, when the reproductive stocks migrate from warmer intertidal and shallow subtidal areas (where fisheries are located), towards spawning grounds in colder and deeper waters. There is a secondary spawning period in winter. On the Pacific coast, reproduction takes place all year round but mainly in spring, and there is no evidence of seasonal bathymetric movements, so different stages of the life cycle can be observed throughout the year. Enteroctopus megalocyathus feeds primarily on brachyuran and anomuran crustaceans, fish and molluscs. It is an important prey item of fishes, elasmobranchs, birds, and marine mammals, and therefore, it has a significant influence on the community dynamics of both oceans.