The ecology of hybrids between the peamouth, Mylocheilus caurinus, and the redside shiner, Richardsonius balteatus, at Stave Lake, British Columbia, Canada

Abstract

Extensive hybridization between the peamouth, Mylocheilus caurinus, and the redside shiner, Richardsonius balteatus, at Stave Lake, British Columbia, provided an opportunity to examine the ecology of hybrid fishes over a 26-year period. Spatial distribution and feeding ecology of the hybrids were compared with those of the parental species. At Stave Lake, M. caurinus was primarily oriented to the limnetic zone at all depths, while R. balteatus was oriented to surface waters in the littoral zone. The hybrids (F1 hybrids and hybrid backcrosses to M. caurinus combined) mimicked the M. caurinus pattern, being significantly more abundant in the limnetic zone. Adult M. caurinus consumed primarily zooplankton with occasional adult insects, while R. balteatus consumed primarily adult insects. The diet of hybrids was not significantly different from that of M. caurinus; they consumed large quantities of zooplankton and some insects.