Do you mean literally without fish, or simply streams where exploitable fish like salmon and trout were absent before stocking? Are there streams in western Canada that are literally fishless? I thought sculpins and sticklebacks between them occurred pretty much throughout. Please correct me if I am mistaken/
mcneely ---- "Emily M. Whattam" <[email protected]> wrote: > Hello all, > > I am conducting the first field season of my Ph.D. this May and will be > surveying Harlequin Duck densities on breeding streams with and without fish > in British Columbia and Alberta (see below for a brief project description). > > I am looking for any tips for potential field sites. I am particularly > interested in tips regarding possible locations of fishless Harlequin Duck > breeding streams, since we suspect that these will be more difficult to find. > > Please let me know if you have any suggestions for potential field sites, or > ideas of people I should contact. > > Much thanks, > > Emily > > PROJECT DESCRIPTION: > > Harlequin duck populations have experienced a slow decline for decades, > particularly in Eastern Canada. Population surveys show that recruitment is > too low to offset mortality. The widespread introduction of fish to > historically fishless breeding streams may be responsible. The presence of > fish lowers the availability of aquatic invertebrates by altering > anti-predator behaviours including downstream drift, daytime hiding, and > nocturnal activity. Lower availability of this key resource may lead to > higher female mortality during incubation, or lower productivity or juvenile > survival. Both Harlequins and fish are found in higher densities in regions > with high invertebrate abundance, but their presences are negatively > correlated. As such, breeding streams containing fish may be of lower quality > and able to support fewer nesting females than fishless streams. I will > determine whether fish lower the quality of breeding streams by quantifying > invertebrate abundance, female condit! io! > n, clutch size, hatching success, fledging success and mean productivity of > Harlequins nesting on paired streams with and without fish. > > Emily M. Whattam > Ph.D. Student > Centre for Wildlife Ecology, TASC 2 8540 > Simon Fraser University > Department of Biological Sciences > 8888 University Drive > Burnaby BC Canada V5C 1S6 > (778) 926-5440 -- David McNeely
