Water Stewardship Information Sources

Citation Nowosad, DM and Taylor, EB. 2013. Habitat variation and invasive species as factors influencing the distribution of native fishes in the Lower Fraser River Valley, British Columbia, with an emphasis on brassy minnow (Hybognathus hankinsoni). Canadian Journal of Zoology 91:71-81.
Organization UBC
URL http://www.zoology.ubc.ca/~etaylor/N&T2013.pdf
Abstract/Description or Keywords Brassy minnow (Hybognathus hankinsoni Hubbs, 1929) have disjunct distributions in western Canada, making them
a species of conservation concern. We assessed changes in the distribution of invasive species as factors influencing the
distribution of brassy minnow and other native species by comparing historical and current distributions in the lower
Fraser River in British Columbia. We tested effects of physical habitat parameters on local distributions of brassy minnow
and for evidence of negative interactions between brassy minnow and invasive brown bullhead (Ameiurus nebulosus (Lesueur,
1819)). Comparison of contemporary and historical (1956 and 1959) fish distributions indicated significant declines in native
cypriniform (minnows and suckers) species, including brassy minnow, but no change in the number of invasive species,
although there was some faunal turnover. Logistic regression suggested that conductivity, turbidity, and water temperature
were important predictors of brassy minnow presence. Appearances of adult-sized brown bullhead at one site corresponded
with reduced abundance of native fishes. In growth experiments with brassy minnow, brown bullhead, and
redside shiner (Richardsonius balteatus (Richardson, 1836)), brassy minnow exhibited mass loss and mortalities, suggesting
that they were poor competitors. Our results contribute to a better understanding of abiotic and biotic factors affecting
distribution and persistence of brassy minnow.
Information Type Article
Regional Watershed Lower Fraser
Sub-watershed if known
Aquifer #
Project status complete
Contact Name Eric Taylor
Contact Email [email protected]