Stirring, charging, and picking: hunting tactics of potamotrygonid rays in the upper Paraná River
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Data
2009-03-01
Autores
Garrone-Neto, Domingos [UNESP]
Sazima, Ivan
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Ictiologia
Resumo
As táticas de caça de raias potamotrigonídeas permanecem sem registro sob condições naturais. Três táticas de forrageamento são aqui descritas para Potamotrygon falkneri e P. motoro, com base em observações subaquáticas no curso superior do rio Paraná. Ambas as espécies apresentaram comportamento semelhante. A tática mais comum foi a de ondular as margens do disco próximo ao, ou no, fundo e assim perturbando o substrato e revelando presas abrigadas. Outra tática foi a de investir sobre presas concentradas no raso. A tática menos frequente foi a de apanhar presas aderidas ao substrato. A primeira tática é comum em diversas espécies de raias marinhas da família Dasyatidae, ao passo que as outras duas (em particular apanhar presas em substratos acima da superfície da água) podem estar restritas a Potamotrygonidae.
Hunting tactics of potamotrygonid freshwater rays remain unreported under natural conditions. Three main foraging tactics of Potamotrygon falkneri and P. motoro are described here based on underwater observations in the upper Paraná River. Both species displayed similar behaviors. The most common tactic was to undulate the disc margins close to, or on, the bottom and thus stirring the substrate and uncovering hidden preys. Another tactic was to charge upon prey concentrated in the shallows. The least common tactic was to pick out prey adhered to the substrate. The first tactic is widespread in several species of marine rays in the Dasyatidae, whereas the remainder (especially picking up prey on substrata above water surface) may be restricted to the Potamotrygonidae.
Hunting tactics of potamotrygonid freshwater rays remain unreported under natural conditions. Three main foraging tactics of Potamotrygon falkneri and P. motoro are described here based on underwater observations in the upper Paraná River. Both species displayed similar behaviors. The most common tactic was to undulate the disc margins close to, or on, the bottom and thus stirring the substrate and uncovering hidden preys. Another tactic was to charge upon prey concentrated in the shallows. The least common tactic was to pick out prey adhered to the substrate. The first tactic is widespread in several species of marine rays in the Dasyatidae, whereas the remainder (especially picking up prey on substrata above water surface) may be restricted to the Potamotrygonidae.
Descrição
Palavras-chave
Potamotrygonidae, Potamotrygon falkneri, Potamotrygon motoro, Variable hunting tactics, Southwestern Brazil
Como citar
Neotropical Ichthyology. Sociedade Brasileira de Ictiologia, v. 7, n. 1, p. 113-116, 2009.