With the increasing emphasis to replace fish meal (FM) with less expensive protein sources in aquaculture diets without reducing weight gains, an 8‐wk feeding trial was conducted with juvenile (15 g) sunshine bass Morone chrysops×M. saxatilis) to evaluate growth and body composition when fed diets with different levels of FM (0, 7.5, 15, and 30%). Six practical floating diets were formulated to contain 40% protein and similar energy levels, with various percentages of FM, meat‐and‐bone meal (MBM), soybean meal (SBM), poultry by‐product meal (PBM), and/or distillers grains with solubles (DGS). Ten fish were stocked into each of 24 110‐L aquaria and were fed twice daily ad libitum (0730 and 1600 h). At the conclusion of the feeding trial, final weights of fish fed diet 2 (0% FM, 29% SBM, 29% MBM, and 10% DGS), diet 3 (0% FM, 32% SBM, and 28% PBM), diet 5 (15% FM and 44% SBM), and diet 6 (30% FM and 26% SBM) were not significantly different (P > 0.05) and averaged 72 g. However, final weights of sunshine bass fed diet 1 (0% FM, 30% SBM, and 31% MBM) and diet 4 (7.5% FM and 54% SBM) were significantly lower and averaged 55 g. Specific growth rate (SGR) of sunshine bass fed diet 4 was significantly lower (2.14) than fish fed diet 2 (2.70), diet 3 (2.80), diet 5 (2.68), and diet 6 (2.84), while feed conversion ratio (FCR) of fish fed diet 4 was significantly higher than sunshine bass fed diets 2, 3, 5, and 6. Carcass (fish were decapitated) composition of sunshine bass fed diet 4 had a significantly higher percentage of moisture (70%) and protein (54% on a dry‐matter basis) than fish fed all other diets. Percentage lipid was similar among fish fed all diets and averaged 41% (dry‐matter basis). Results from the present study indicate that diets in which all of the FM is replaced with a combination of animal‐ and plant‐source proteins can be fed to sunshine bass without adverse effects on weight gain, growth rate, and body composition. Further feeding trials are needed to refine diet formulations used in the present study and should be conducted in aquaria and ponds.

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The culture of yellow perch Perca flavescens has received considerable interest in the Midwest and elsewhere in the USA as a result of the decline of wild populations and their high market demand. In this study, the effects of size‐grading on the production efficiency and growth performance of food‐sized yellow perch were determined in six 0.1‐ha ponds by grading fingerlings into three size‐groups (mean initial size): small (5.3 g), large (18.3 g), and unsorted (11.3 g). The mean percentage of marketable production from large‐group ponds was significantly greater than that from the small‐ and ungraded‐group ponds. The final biomass of large size‐groups was 77% and 27% greater than that of small and ungraded groups, respectively, although no significant differences in total production were detected among the three size‐groups. Size‐sorting of fingerling yellow perch did not result in improved growth of the small‐fish group. No significant differences in growth rates among the three groups were detected in either the first half‐year (winter–spring) or the second half‐year (summer–fall) period. The growth performance of the three groups indicates that yellow perch populations under culture conditions experience a bimodal growth pattern, with two distinct size‐groups. The coefficient of variation (CV) in both weight and length for the small‐group fish increased about 80%, whereas the CV in the ungraded and large groups showed some reduction. The results indicate that grading by size should be advantageous to those wishing to culture yellow perch to food fish size in the second year. The significantly different results for the percentage of fish reaching market size among the large (65%), ungraded (53%), and small (35%) groups suggest that perch should be selectively graded by at least the end of one year of intensive culture to increase the number of individuals with the potential to reach market size.

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