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Low survival and quality of early life-stage bluegill is an obstacle to viable production where size may influence weaning efficiency. Herein, we investigate through two trials the effects of fry size 12-d post-exodus on total length, weight, production and survival through 56-d post-exodus. Full sibling broods (trial 1=10, trial 2=6) were reared with feedings of brine shrimp Artemia sp. nauplii (BS) through 12-d post-exodus (PE). Broods of trial 1 were visual sorted 12 d PE into small and large size groups. Fry (n = 25) from each size group were sampled for measured total length (TL) and weight. Starting 14 d PE, a 7-d co-feeding period with a commercial dry feed (#0 crumb) that was continued through 27 d PE with subsequent feedings using a larger version (#1 crumb) of the same diet continuing through 56 d PE (trial end). Broods of trial 2 were split 4 d post-conception into two gorups of pro-larvae (n = 400). Slow growing groups were fed hourly 0800-1700 while fast growing were fed additionally at 0400 and 2200 through 12 d PE. Surviving fish from each size gorup were collected, with random samples (n = 25 fish) measured for TL and weight. Fry (n = 100 where possible) were placed into 151-L aqauriums with slow and fast growing feed regimens maintained through 13-d PE. Culture regimen thereafter was same as trial 1. Fish of both trials were harvested, measured for TL, weight, and survival. The Wilcoxon Signed Rank Test was run one-tailed using SAS. Results of trial 1 indicate size at 12 d was a predictor of TL, weight and survival through 56 d PE (p ≤ 0.156). Size variation at 12 d as a function of genetics is a predictor of growth and survival through 56 d while at least some size variation resulting from early growth rate differences can be overcome by compensatory growth.
Bluegill, Bluegill larvae, Aquaculture--Research, Bluegill--Growth, Bluegill--Feeds and feeding
Aquaculture and Fisheries
Schulte, J.L. and Wetzel, James E., "The Size Relationship of 12 Days Post-Exodus Larvae with 56 Day Post-Exodus Fingerlings Regarding Growth and Survival in Bluegill (Lempomis macrochirus)" (2016). Cooperative Extension Research Publications. 8.