Feeding habits and mouth osteology of silverside, Odontesthes humensis de Buen (Atheriniformes, Atherinopsidae) in the Mirim Lagoon, Rio Grande do Sul, Brazil

Gut contents of 304 individuals of the silverside Odontesthes humensis de Buen, 1953 were analyzed using frequency of occurrence (FO%) and gravimetric (P%) methods. A total of 207 individuals (68.1%) had some food itens in the gut, while 97 individuals (31.9%) had empty guts. The silverside Odontest...

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Bibliographic Details
Published in:Revista brasileira de zoologia 2001-09, Vol.18 (3), p.793-802
Main Authors: Rodrigues, F L, Bemvenuti, MA
Format: Article
Language:Portuguese
Subjects:
Brackish
Marine
Odontesthes humensis
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Summary:Gut contents of 304 individuals of the silverside Odontesthes humensis de Buen, 1953 were analyzed using frequency of occurrence (FO%) and gravimetric (P%) methods. A total of 207 individuals (68.1%) had some food itens in the gut, while 97 individuals (31.9%) had empty guts. The silverside Odontesthes humensis has presented a benthic carnivorous diet, preying mainly on molluscs and arthropods. The molluscs Heleobia sp. (FO = 61.35%) and Corbicula fluminea (FO = 57.97%) were the most frequent itens, followed by Neocorbicula limosa (FO = 17.39%). Among the arthropods, the coleoptera insects (FO = 18.84%) were dominant followed by, insect larvae (FO = 6.76%), the crustacean Palaemonetes argentinus Nobili, 1901 (FO = 1.93%) and isopods (FO = 1.45%). Vegetal remains, organic matter and digested fish were grouped due to low frequency (FO = 9.13%) being considered occasional. Juvenile fed mainly on insect larvae and molluscs, while the adults preferred molluscs and coleoptera. On the description of its feeding apparatus the importance of a protrusible upper jaw was observed, being important on the capture of prey in inaccessible places. A protrusible mouth and the format of the pharingean plates, are important morphological characters that assist on the capture and handling of prey. The molariform shaped pharingean teeth help break hard food items, as shells and carapaces.
ISSN:0101-8175