PERFORMANCE COMPARISON AND GROWTH-MODELS FOR WALLEYES AND WALLEYE X SAUGER HYBRIDS REARED FOR 2 YEARS IN INTENSIVE CULTURE

To aid in evaluating the potential of walleye (Stizostedion vitreum) a nd hybrid walleye x sauger (S. vitreum female x S. canadense male) as commercial food fish (greater than or equal to 681 g, a minimum size f or the food fish market), we compared the growth, survival, condition factor, and feed conversion of advanced fingerling (284 mm initial tot al length) walleyes and walleye hybrids reared in intensive culture at 20.7 degrees C. Survival of both groups was 90% or better during the 126-d study. None of the differences in performance between the two gr oups were significant. The hybrids grew in length from 283 to 330 mm ( 0.37 mm/d) and in weight from 199 to 325 g (1.01 g/d). The walleyes gr ew in length from 285 to 324 (0.31 mm/d) and in weight from 201 to 318 g (0.94 g/d). Data from this cohort grown under intensive culture con ditions to an age of 783 d posthatch were used to develop a comprehens ive growth curve model for hybrids and walleyes from hatch to 681 g. T he model accounted for 98-99% of the variability of the weight. Predic tions from this model indicate walleye hybrids grow faster than walley es at lengths less than 325 mm, but walleyes would reach the minimum m arket weight 31 d sooner than the hybrids. The study does not discount the aquacultural potential for walleye hybrids, but does suggest the need for further study before hybrids are chosen in preference to wall eyes.