Within-population variability in egg characteristics of walleye (Stizostedion vitreum) and white sucker (Catostomus commersoni)
I examined variation in egg characteristics among individual females of sympatrically spawning walleye (Stizostedion vitreum) and white sucker (Catostomus commersoni) from Lake Manitoba. White sucker produced eggs of greater dry mass and energy content than walleye. Walleye egg dry mass varied between years and was positively related to both female length and age. The relationship between white sucker egg dry mass and female length varied between years. Egg energy density did not vary with respect to female length in either species. Egg energy density varied between years for walleye but not white sucker. Hatching success of walleye eggs was positively related to female age and negatively related to female length adjusted for age. Length and dry mass of walleye larvae at hatch increased with egg dry mass. Results suggest that the quality of eggs produced by walleye and white sucker populations may vary with the size and age structure of the populations and among spawning years.