Winter is cool: spatio temporal patterns of the squat lobster Munida gregaria and the Fuegian sprat Sprattus fuegensis in a sub‑Antarctic estuarine environment

DIEZ, M.; CABREIRA, A; MADIROLAS, A; MARTIN, J; SCIOSCIA, GABRIELA; SCHIAVINI, ADRIÁN; LOVRICH, G.A.

POLAR BIOLOGY

SPRINGER

Lugar: Berlin; Año: 2018 vol. 41 p. 2591 - 2605

0722-4060

In the sub-Antarctic waters of southern South America, two species that form conspicuous pelagic aggregations are consideredboth potential fishery resources and ecologically important: the Fuegian sprat Sprattus fuegensis and the squat lobsterMunida gregaria. Here, we estimate spatio-temporal patterns of the relative abundance, distribution and potential areas ofoverlapping of M. gregaria and S. fuegensis in the Beagle Channel. Acoustic data were collected from 18 surveys conductedbetween 2009 and 2016 in the Beagle Channel. Our observations on the pelagic aggregations revealed that M. gregariaswarms and S. fuegensis schools occurred along the channel throughout the year. However, the occurrence of S. fuegensiswas more evident in the inner part of the channel during the winter. There was a negative relationship between the relativeabundance of squat lobsters and Fuegian sprats throughout the year. This interaction may result from spatial competitionassociated with resources, particularly in summer. The vertical distribution and morphology of aggregations of both speciesshowed seasonal differences. Specifically, schools of Fuegian sprats were typically pelagic in summer, whereas in winterthey were bigger and associated with the bottom layer. This change could be associated with a seasonal change in the oceanographicregime of the Beagle Channel. The information presented here is necessary to understand processes in a contextof possible opening of fisheries targeting these two species that have key ecological roles in this sub-Antarctic ecosystem.