The Fish Communities of the Toronto Waterfront: Summary and Assessment 1989 - 2005
THE FISH COMMUNITIES OF THE TORONTO WATERFRONT: SUMMARY AND ASSESSMENT 1989 - 2005 SEPTEMBER 2008 ACKNOWLEDGMENTS The authors wish to thank the many technical staff, past and present, of the Toronto and Region Conservation Authority and Ministry of Natural Resources who diligently collected electrofishing data for the past 16 years. The completion of this report was aided by the Canada Ontario Agreement (COA). 1 Jason P. Dietrich, 1 Allison M. Hennyey, 1 Rick Portiss, 1 Gord MacPherson, 1 Kelly Montgomery and 2 Bruce J. Morrison 1 Toronto and Region Conservation Authority, 5 Shoreham Drive, Downsview, ON, M3N 1S4, Canada 2 Ontario Ministry of Natural Resources, Lake Ontario Fisheries Management Unit, Glenora Fisheries Station, Picton, ON, K0K 2T0, Canada © Toronto and Region Conservation 2008 ABSTRACT Fish community metrics collected for 16 years (1989 — 2005), using standardized electrofishing methods, throughout the greater Toronto region waterfront, were analyzed to ascertain the current state of the fish community with respect to past conditions. Results that continue to indicate a degraded or further degrading environment include an overall reduction in fish abundance, a high composition of benthivores, an increase in invasive species, an increase in generalist species biomass, yet a decrease in specialist species biomass, and a decrease in cool water Electrofishing in the Toronto Harbour thermal guild species biomass in embayments. Results that may indicate a change in a positive community health direction include no significant changes to species richness, a marked increase in diversity in embayments, a decline in non-native species in embayments and open coasts (despite the invasion of round goby), a recent increase in native species biomass, fluctuating native piscivore dynamics, increased walleye abundance, and a reduction in the proportion of degradation tolerant species.
[Show full text]