Occurrence and biological aspects of the Atlantic brief squid Lolliguncula brevis in the estuary of São Vicente-SP, southeastern Brazil.

The population structure and environmental influences for the Atlantic brief squid Lolliguncula brevis (Blainville, 1823) were studied in the estuary of Sao Vicente, southern Brazil between September 2009 and April 2010. Samples were obtained by a shrimp otter-trawl of 7.5 m length with 15 mm in the main net and 10 mm in the drawer that covered eight sampling stations, four in the estuarine area and four in the marine area, at depths between 2.5 and 14.3 meters. A total of 1,252 cephalopods were captured all of them Lolliguncula brevis . The occurrences were notably marine being only three specimens collected in the estuary. The mantle lengths from 757 specimens ranged between 9 and 72 mm. The Length-Weight relationship for the species was obtained for 277 individuals of both sexes resulting in WT = 0.0005094 MT 2.44 (r 2 = 0.8974), with most stages of sexual maturation represented by mature and maturing for 33 males and 43 females analyzed, both matures when larger than 50 mm ML. The present research showed that L. brevis is an important component of the coastal ecosystem in the Santos-Sao Vicente Bay, present in higher abundance during summer in the marine area and virtualy absent in the estuary, were probable causes of predation, channel depth, and pollution may inflence the population distribution.