Status of the Enos Lake stickleback species pair, Gasterosteus spp.

Abstract

A sympatric pair of stickleback species (Gasterosteus spp.) occurs in Enos Lake on Vancouver Island [British Columbia, Canada]. These species are reproductively isolated and are adapted to alternative trophic niches. One members of the pair (the "limnetic" species) is a pelagic plankton-feeder whereas the other member (the "benthic" species) is a littoral benthos-feeder. Although both species occur in large numbers, they are restricted to one small lake in an area of rapid urban development. The major short-term threat to this unique species pair is the introduction of other fish species. The major long-term threat is urban expansion. Perhaps, to ensure the survival, this species pair might be transplanted to some less developed area.