Summary: | The dusky grouper Epinephelus marginatus has a broad global distribution and is currently listed as an endangered species at the IUCN Red List. This species has large commercial and ecological importance, but only at the last decade the first studies were carried out on its bioecology at its southernmost distribution limit in Southwestern Atlantic. This region is largely formed by sand bottoms, where the occurrence of reefs and rocks are scarce. Rocky bottoms occur in the neritic region (along 20 to 30 m isobaths) and in the jetties in the littoral region, and in both areas the dusky grouper occur frequently. Our studies showed that immature individuals (mean: 4 yrs) of dusky groupers inhabiting rocky jetties in the littoral region represents an important economical incoming for artisanal fishermen, whereas adults (mean: 8 yrs) are mostly caught at offshore banks 15-25 m deep by coastal fisheries. Microscopic analyses of gonads of littoral and neritic individuals suggest that the littoral region is a growing nursery area and the neritic is a reproductive site. Feeding ecology studies based on stomach content and stable isotopes showed that the species has an important role as top predators in both regions. Future studies on the residence time of immature individuals in the littoral using telemetry are fundamental to further understand the ecology of this endangered species in the Southwestern Atlantic and to help its fishing management and conservation.
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