Freshwater ecosystems are usually considered as vulnerable because of various anthropogenic disturbances through recreational fisheries, agricultural and industrial effluent releases, and habitat degradation. These factors combined with complex ecological processes and the diffuse nature of freshwater fisheries could lead to a drastic loss in aquatic habitat and freshwater fish stocks. Given the potential of fish exploitation and habitat loss to influence conservation or management, it is important to critically assess the productive capacity of fish habitat for the available data and specific environment considered. This study used major freshwater fish species captured by boat electrofishing at Lake Ontario wetlands in 2018 and 2019 to estimate fish production for measuring habitat productive capacity. Instantaneous growth rate method was used for estimating fish production rates. Species-specific production rate per unit biomass (P/B, per year) ratios based on allometry with fish size and the habitat productivity index (HPI) were also analyzed and compared with fish production estimation to assess their ability in measuring the productive capacity of fish habitat.
Results/Conclusions
Eight fish species that took over 96.5% of the fish biomass captured by boat electrofishing at Lake Ontario wetlands were included for estimating fish production in this study: Bowfin, Brown Bullhead, Largemouth Bass, Pumpkinseed, Yellow Perch, Northern Pike, Bluegill, and Black Crappie. Bayesian hierarchical models were approximated using Markov Chain Monte Carlo (MCMC) methods to estimate fish growth rate and mortality rate from fish age, size, and abundance data. Results suggested that Yellow Perch, Pumpkinseed, and Largemouth Bass are the most important fish species for assessing fish production and measuring habitat productive capacity in Lake Ontario wetlands. The estimation of production rate per unit biomass (P/B, per year) ratios based on allometry with fish size and the habitat productivity index (HPI) were significantly correlated with the fish production estimated using instantaneous growth rate method for the eight species in this study. The P/B ratios and HPI indices can be used as efficient tools for measuring fish community biomass and evaluating the productive capacity of fish habitat in Lake Ontario wetlands.