The environmental basis of diet variation in pumpkinseed sunfish, Lepomis gibbosus, and largemouth bass, Micropterus salmoides, along an Iberian river basin |
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Authors: | FranciscoNunes Godinho Maria Teresa Ferreira Rui Victor Cortes |
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Institution: | 1. Esta??o Florestal Nacional, Posto Apíola, Tapada da Ajuda, 1300, Lisboa, Portugal 2. Departamento de Engenharia Florestal, Instituto Superior de Agronomia, Tapada da Ajuda, 1399, Lisboa, Portugal 3. Departamento Florestal, Universidade de Trás-os Montes e Alto Douro, 5000, Vila Real, Portugal
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Abstract: | The diet composition of largemouth bass, Micropterus salmoides, and pumpkinseed sunfish, Lepomis gibbosus, and its relation
to environmental factors was studied in intermittent watercourses of the lower Guadiana basin (southern Iberia) during the
particularly dry summer of 1994. Overall, both species took food items similar to those found in their North American and
acclimatised ranges, with pumpkinseed consuming invertebrates (chiefly Chironomidae) and bass preying on invertebrates (chiefly
Micronecta meridionalis) and fish (chiefly L. gibbosus and Gambusia holbrooki). Both bass and pumpkinseed were opportunistic
feeders, feeding on the most frequent and abundant prey. However, Diptera larvae were apparently preferred by pumpkinseed
and avoided by bass, while the contrary occurred with respect to Heteroptera. The two main fish prey of bass were eaten on
the basis of random encounter. The relative abundance of macro-prey (i.e. fish and Atyephira desmarestii) were the principal
environmental variables constraining bass dietary variation along the basin. On the contrary, pumpkinseed diet variation was
mainly related to pumpkinseed size and the presence of piscivorous bass nearby, although habitat size and cyprinid abundance
were also influential.
This revised version was published online in July 2006 with corrections to the Cover Date. |
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Keywords: | exotic Centrarchidae stomach contents environment canonical correspondence analysis rivers Guadiana basin Portugal |
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