LARGEST AGGREGATIONS OF MARINE TUCUXI (Sotalia fluviatlis) IN ILHA GRANDE BAY, RIO DE JANEIRO STATE
Abstract
Between April 1997 and January 1998, 24 cruises for cetacean observation, summing up to 109hrs20min of observation effort, were made in Ilha Grande Bay, Rio de Janeiro State. Groups of marine tucuxis (Sotalia f/uviatilis) consisting of
three to approximately 450 individuais, were observed on eleven occasions. ln 90% ot the sightings, tucuxi groups consisted of adults, juveniles and/or calves. This paper reports the tive largest aggregations known for the marine tucuxi in its distribution area. These large groups consisted of approximately 450 individuais (n=2), 200 individuais (n=2) and 150 individuals(n=1).According to ourobservations and to reports by local inhabitants, these high numbers ofindividuals pergroup may be commonly observed in Ilha Grande Bay, being possibly related to fishing activities, resting and socialization. The possibility of S. f/uviatilis feeding on the bycatch discarded by shrimp boats are discussed.
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References
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