The environmental basis of diet variation in pumpkinseed sunfish, Lepomis gibbosus, and largemouth bass, Micropterus salmoides, along an Iberian river basin

摘要: The diet composition of largemouth bass, Micropterus salmoides, and pumpkinseed sunfish, Lepomis gibbosus, its relation to environmental factors was studied in intermittent watercourses the lower Guadiana basin (southern Iberia) during particularly dry summer 1994. Overall, both species took food items similar those found their North American acclimatised ranges, with consuming invertebrates (chiefly Chironomidae) bass preying on Micronecta meridionalis) fish L. gibbosus Gambusia holbrooki). Both were opportunistic feeders, feeding most frequent abundant prey. However, Diptera larvae apparently preferred by avoided while contrary occurred respect Heteroptera. two main prey eaten basis random encounter. relative abundance macro-prey (i.e. Atyephira desmarestii) principal variables constraining dietary variation along basin. On contrary, mainly related size presence piscivorous nearby, although habitat cyprinid also influential.