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

MARIANO J. DIEZ; ARIEL G. CABREIRA; ADRIAN MADIROLAS; JACOBO MARTIN DE NASCIMIENTO; GABRIELA SCIOSCIA; ADRIAN SCHIAVINI; GUSTAVO A. LOVRICH

POLAR BIOLOGY

SPRINGER

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

0722-4060

In the sub-Antarctic watersof southern South America, two species that form conspicuous pelagic aggregationsare considered both, potential fishery resources and ecologically important:the Fuegian sprat Sprattus fuegensisand the squat lobster Munida gregaria.Here, we estimate spatio-temporal patterns of the relative abundance,distribution and potential areas of overlapping of M. gregaria and S. fuegensisin the Beagle Channel. Acoustic data were collected from 18 surveys conductedbetween 2009 and 2016 in the Beagle Channel. Our observations on the pelagicaggregations revealed that M. gregariaswarms and S. fuegensis schools occurredalong the channel throughout the year. However, the occurrence of S. fuegensis was more evident in theinner part of the channel during the winter. There was a negative relationshipbetween the relative abundance of squat lobsters and Fuegian sprats throughoutthe year. This interaction may result from spatial competition associated toresources, particularly in summer. The vertical distribution and morphology ofaggregations of both species showed seasonal differences. Specifically, schoolsof Fuegian sprats were typically pelagic in summer, whereas in winter they werebigger and associated to the bottom layer. This change could be associated witha seasonal change in the oceanographic regime of the Beagle Channel. Theinformation presented here is necessary to understand processes in a context ofpossible opening of fisheries targeting these two species which have keyecological roles in this sub-Antarctic ecosystem.