Comparisons of Walleye Fecundity Before, During, and After Rehabilitation of the Red Lakes Fishery

Abstract

Abstract The Red Lakes, Minnesota, supported a substantial Walleye Sander vitreus fishery from the early to mid-20th century, but experienced a major crash in the late 1990s. The population has since rebounded following a successful inter-agency recovery program and now supports valuable commercial and recreational fisheries. The variation in population densities associated with the collapse and subsequent recovery in the Red Lakes Walleye population provides a rare opportunity to study potential changes in relative fecundity (eggs/kg of body mass) under varying rates of exploitation: overexploited (1989 data), recovering (2004 data), and recovered (2017 data). Female Walleye were collected spring 1989 (n=30) in the Blackduck and Tamarac rivers and spring 2004 (n=30) and 2017 (n=30) in the Tamarac River. Results indicate relative fecundity was significantly lower in 2017 (50,768, SD=10,266) than in 1989 (58,216, SD=6,211) and 2004 (61,964, SD=7,472). We hypothesize differences in relative fecundity among fishery states were due to differences in Walleye population abundances caused by varying exploitation rates in the years leading up to fecundity estimates.