Chapter10. Octopus tehuelchus, Small Patagonian octopus.

STORERO, LORENA P.; NARVARTE MAITE A.

Biology and Ecology of Octopods

Elsevier Science Publishing Co Inc

Año: 2023;

The small Patagonian octopus inhabits the intertidal and subtidal environments from North Patagonia in Argentina (46° S) to South Brazil (17° S). In San Matías Gulf (40-41° S) the species is exploited by artisanal fishers, who collect octopuses by hand with an iron-gaff in the rocky intertidal or using artificial shelters in the shallow soft bottoms. Octopus tehuelchus is a small octopus (up to 150 g), the mean lifespan is two/three years, and the growth is seasonal. From spring to early fall, coincident with the increasing water temperature, the species shows fast growth, intensive feeding, and sexual maturation. Afterward, with lowering temperature and cold months, feeding rate decreases associated with maturity and breeding condition. Holes in the rocks and empty shells of mollusks are used as shelter from predators and to laid eggs. Embryonic development occurs in winter, with four months of parental care, and hatchlings emerge in spring. Temperature affects the embryogenesis, and individuals show phenotypic plasticity in growth and life span in response to their developmental environment.Octopus tehuelchus is an opportunistic predator that feeds on small mussels, crustaceans, and snails. The consumption of different food sources depends on the state of maturity and the habitat. In the rocky Patagonian shores, this octopus is host of dicyemidae and coccidian parasites, and coexist with other invertebrate consumers probably by differential use of resources and trophic niche partitioning. Research priorities on the small Patagonian octopus should consider the short-term interests related to the biology and ecology along its distribution range, as well as the biological and socio-economic aspects of the fishery, but also research should consider long-term future interests and scenarios related to the ecological role of octopuses in the coastal ecosystems, and the potential changes in species interactions due to the expected global changes.