Analysis of food habits of skate Rioraja agassizii (Elasmobranchii, Rajidae) from southern Brazil
Catches and exports of skate Rioraja agassizii place this species as "vulnerable to extinction" on the IUCN Red List; therefore, biological and ecological knowledge becomes an important instrument for its conservation control. This study described and quantified the diet composition of R....
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Published in | Brazilian journal of biology Vol. 76; no. 2; pp. 469 - 475 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English Portuguese |
Published |
Brazil
Instituto Internacional de Ecologia
01.06.2016
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Subjects | |
Online Access | Get full text |
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Summary: | Catches and exports of skate Rioraja agassizii place this species as "vulnerable to extinction" on the IUCN Red List; therefore, biological and ecological knowledge becomes an important instrument for its conservation control. This study described and quantified the diet composition of R. agassizii by means of stomach analysis contents in the periods 2005-2006 and 2012-2013. We analyzed and quantified stomach contents in terms of abundance (%N), weight (%M), frequency of occurrence (% FO), and index of relative importance (IRI). The results showed differences in the food rates between the periods. However, the groups of food items were the same: Teleostei fish, decapods, and mollusks. In 2005-2006, the diet consisted mainly of shrimp, however, in 2012-2013 it consisted of fish, followed by decapods, especially shrimps. The differences in diets may be attributed to shrimp abundance, which do not characterize a change in the eating habits in 2012-2013, because, in addition to fish, shrimps were also important food sources. The presence of a certain prey is more related to its availability rather than the feeding preference of skate. The amount of ingested items is associated to biological and environmental factors, so that further studies relating diet with capture area, seasonality, depth, and other factors should be conducted. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1519-6984 1678-4375 1678-4375 |
DOI: | 10.1590/1519-6984.21414 |