Ecology of forage fish following cessation of overharvest of walleye in Henderson Lake, Ontario

Abstract

I examined the forage base of Henderson Lake, Ontario following collapse of its walleye stock due to overexploitation, and an inexplicable decline of the ninespine stickleback population. In response to these events a very large yellow perch year class was produced. Subsequently, adult perch density increased while growth, mortality, size at maturity and fecundity decreased. Continued stunting in young yellow perch could not be attributed to direct interspecific competition with abundant shiners. As northern pike activity increased shiner activity declined but yellow perch remained active and available as prey. Thus, small perch occurred much more frequently in the diets of northern pike than did shiners. The large numbers of stunted yellow perch may provide excellent forage for enhancing the recovery of the walleye population.