Influence of habitat structure on the fish prey consumption by largemouth bass, Micropterus salmoides, in experimental tanks

Abstract

The largemouth bass, Micropterus salmoides, was introduced into the Iberian Peninsula in the 50's and has developed important populations in systems naturally lacking native piscivores. As a consequence, the displacement of native cyprinids has been associated with its predatory behaviour, particularly in reservoirs. In order to study the capture rate of largemouth bass in relation to an Iberian native cyprinid, Squalius alburnoides, and also to pumpkinseed, Lepomis gibbosus -another exotic species introduced to Iberia that is able to coexist sucessfully with bass in Iberian systems-tanks were used to simulate the absence of structure, and the presence of vegetation struture and bottom structure. The number of fish captured by largemouth bass were influenced by both structure and prey effects, as well as by their interaction. The bottom and vegetation structure reduced the number of pumpkinseed captured when compared with the absence of structure, whereas only the vegetation reduced the number of Squalius alburnoides captured. Neither the pumpkinseed nor the cyprind were eaten more frequently by largemouth bass in the absence of structure or in the vegetation structure, but the cyprinid was eaten more frequently in the bottom structure. © Asociación Española de Limnología.