Historical changes in the fish communities of the Credit River watershed

Session: 12. - History of Great Lakes Fish, Fisheries & Governance: Dr. Henry Regier's Legacy

Brett Allen, University of Toronto, [email protected]
Nicholas Mandrak, Biological Sciences, University of Toronto Scarborough, [email protected]

Abstract

Watersheds in southern Ontario are of high conservation concern due to their diverse fish communities, productive environments, and threats from numerous anthropogenic stressors. The Credit River watershed, located west of the Greater Toronto Area, has 63 fish species and multiple stressors, including urbanization, climate change, and aquatic invasive species (AIS). This research examines fish community change in the Credit River watershed in relation to these multiple stressors. Historical fish datasets collected in the watershed from 1954 to present were analyzed to examine species distribution and richness patterns. Over time, distribution was widespread and stable for 43 of the 63 species, increasing for eight species, limited and stable for seven species, and declining for two species. Species richness increased at the site and subwatershed level over time. AIS and temperature were responsible for causing the most variation in the fish communities over time.

1. Keyword
fish

2. Keyword
invasive species