Analysis of stomach contents of the smalltail shark Carcharhinus porosus from Northern Brazil

Lessa R., Almeida Z.

Published date: April 1997
Volume: 21
Number: 2
Pagination: 123-133
Publisher: Société Française d'Ichtyologie
doi: https://doi.org/10.26028/cybium/1997-212-001
Abstract

Feeding habits of the smalltail shark, Carcharhinus porosus, were investigated by analyzing stomach contents of 684 specimens caught between 1984 and 1987 in coastal waters off Maranhão state (Northern Brazil). Twenty five percent of the stomachs contained food, 80% of which (numerically) were fish. Main prey items consisted of croakers (Sciaenidae) Macrodon ancylodon and Stellifer naso. All fish species present in the stomach contents are abundant in shallow waters, suggesting that C. porosus is an opportunistic predator. The highest proportions of empty stomachs were observed from September to November in both juveniles and adults. The mean weight of full stomachs ranged from 40 to 60 g in adults, and from 20 to 25 g in juveniles. On average, both juveniles and adults had one prey item in their stomachs. Adults may prey upon Elasmobranchs, whereas juveniles showed a wider food spectrum. Ontogenic differences in diet were observed for both males and females. The evidence presented shows that size selection of prey is related to predator size.

Keywords: ASW - Carcharhinidae - Carcharhinus porosus - Equatorial Atlantic Coast - Shark diet - Stomach contents
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