Feed training is a crucial aspect of largemouth bass (LMB) production, particularly in commercial aquaculture systems where artificial pelleted feeds are used to minimize cannibalism and optimize growth. Traditionally, LMB fingerlings are produced in managed nursery ponds; however, floating in-pond raceways represent a potential alternative rearing system that could enhance production efficiency by reducing space and operational costs. This study compares the feed training efficiency, survival rates, and growth performance of Phase I LMB fingerlings produced in managed nursery ponds and floating in-pond raceways.
This 3-week study evaluates feed training efficiency among fish grown in a managed nursery pond (control) and a floating raceway (treatment). Treatments were randomly assigned to aquariums (132L) supplied with a flow of water at 27°C and aeration. They were stocked with fish harvested from managed nursery ponds (2.68 ±.03 g/fish) and floating raceways (0.72 ± .02 g/fish). Each aquarium was stocked with 200 fish and fed to satiation with a pelleted feed (50% protein 10% fat). Amount fed was recorded. Temperature, dissolved oxygen, total ammonia nitrogen and nitrite were monitored. The number of fish in each aquarium and batch weight of each aquarium was recorded at stocking and harvest.
The results showed that both groups of fish successfully adapted to the pelleted feed, with high survival rates observed for both treatments: 95.5% for pond-reared fish and 96.5% for raceway-reared fish. However, significant differences were noted in specific growth rates (SGR) and final harvest densities. Raceway-reared fish had a higher SGR (8.3 ± 0.26 %BW/day) compared to pond-reared fish (4.8 ± 0.07 %BW/day), likely due to their smaller initial size. Feed efficiency for pond and raceway treatments was 119% and 109%, respectively. It was not significantly different.
The findings of this study suggest that floating in-pond raceways can produce LMB fingerlings that feed train as effectively as those reared in managed nursery ponds. Otohime feed was well accepted and highly efficient.