Title: Evaluation of larval hybrid striped bass Morone chrysops x M. saxatilis growth under three different dietary feeding regimes in two recirculating tank systems: Green water vs. clear water Authors
Submitted to: Book of Abstracts Aquaculture America
Publication Type: Abstract Only
Publication Acceptance Date: October 11, 2012
Publication Date: February 21, 2013
Citation: Mcentire, M.E., Riche, M.A., Rawles, S.D. 2013. Evaluation of larval hybrid striped bass Morone chrysops x M. saxatilis growth under three different dietary feeding regimes in two recirculating tank systems: Green water vs. clear water[abstract]. Book of Abstracts Aquaculture America 2013: Strike a Chord for Sustainable Aquaculture, February 21-25, 2013, Nashville, Tennessee. p.713. Technical Abstract: Optimizing growth of larval hybrid striped bass (HSB) in closed tank systems is important because it allows for more environmental control and predictable production of feed trained fingerlings that do not rely on seasonal variation nor pond blooms. The purpose of this study was to further optimize conditions for growing larval HSB in tanks, particularly to reduce cannibalism and shorten the period that live feed must be supplied. The study was conducted as a 2 water treatment x 3 feeding regime factorial experiment over a 25-d period. Two 12-tank (110 L/tank; 24 tanks total) recirculating systems were filled with either untreated well water 'clear' or 'green' water by adding 40 mL of Nannochloropsis paste to system sumps daily. Salinity was maintained at 5ppt daily with the addition of Instant Ocean (c) Sea Salt to system sumps. Fry were stocked at a rate of 65 fry/L or 7,150/tank. Four replicate tanks were randomly assigned to one of three feeding regimes (regular, short, or u-diet) in each 12-tank system. The regular feeding regime consisted of 8 d on rotifers, 3 d on micro-cysts (overlapping 1 d with), regular artemia for 15 d, and salmon starter starting the last 5 d of the trial. The short regime consisted of 4 d on rotifers, 6 d on micro-cysts (overlapping 1-d with), regular artemia for 10 d, and transitioning to salmon starter the last 8 d. The micro (u-) diet regime consisted of 3 d on rotifers, 6 d on micro-cysts, 3 d on regular artemia (overlapping the transition to), micro particulate diet the last 17 d of the trial. At least 20 fry were photographed from each tank on day 8, 16 and 25 of the trial. Morphometric parameters were measured from photographs and tank means were subjected to ANOVA. Random samples of fry were also collected from each tank for fatty acid analysis. Fry survival was highly variable in all treatments with no discernible pattern. Feeding regime drastically influenced fry length with fry on the regular and short feeding regime being longer after 16 and 25 days than those on the micro-particulate diet, which under performed in terms of growth. Water treatment did not statistically affect fry length due to size variation in the clear water.