Measured and predicted compositional responses of a fish community to the restoration of a degraded urban coastal wetland (Ontario)

Multivariate analysis was used to determine changes to the fish community in Cootes Paradise wetland once the “fishway” became functional at reducing carp. Detected differences in the community between pre- and post-fishway years included an increase in occurrences of yellow perch and northern pike, as well as a decrease in occurrences of carp and goldfish. Two empirical models were developed to assess directional changes of the wetland's fish community over the last 60 years and make predictions about the species composition in Cootes Paradise following restoration. Changes were characterized by a decline in the presence of native species between the 1950s and 1970s, followed by a partial recovery of native species composition in the 1980s and 1990s. Using the position of the trajectory's end point in the model and information about the species current status in Lake Ontario, a fish community with historical fish species and current exotics was predicted.