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Evaluation of Cottonseed Meal Supplementation of Inorganically Fertilized Florida Largemouth Bass Spawning Ponds
Author(s) -
Kurten Gerald,
Hall Lee,
Thompson Neil
Publication year - 1999
Publication title -
north american journal of aquaculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 41
eISSN - 1548-8454
pISSN - 1522-2055
DOI - 10.1577/1548-8454(1999)061<0115:eocmso>2.0.co;2
Subject(s) - biology , cottonseed meal , bass (fish) , fishery , fish meal , zoology , cottonseed , meal , aquaculture , aquatic animal , agronomy , soybean meal , ecology , fish <actinopterygii> , microbiology and biotechnology , food science , raw material
Spawning ponds of Florida largemouth bass Micropterus salmoides floridanus were fertilized with liquid inorganic fertilizers and either cottonseed meal (CSM) or no cottonseed meal (NOCSM) to evaluate the effects of organic fertilization on largemouth bass fry production, plankton densities, and water quality. Each treatment consisted of eight replicate ponds. All ponds of both treatments were subjected to the same inorganic fertilization regimen. Nitrogen and phosphorus levels were similar between treatments. Morning and afternoon dissolved oxygen levels were significantly lower in CSM ponds than in NOCSM ponds throughout much of the culture period. Levels of total CO 2 were significantly higher in CSM ponds than NOCSM ponds. Higher total CO 2 concentrations apparently contributed to significantly lower pH levels in CSM than in NOCSM ponds. Phytoplankton biomass preceding crustacean zooplankton density peaks was significantly higher in CSM than in NOCSM ponds. Cladoceran and rotifer densities were similar between treatments, but densities of adult copepods were significantly higher in CSM than in NOCSM ponds. Mean fry density and mean fry length at harvest were similar between treatments; however, mean fry biomass from CSM ponds was significantly heavier than from NOCSM ponds. These findings suggest that cottonseed meal supplementation of inorganically fertilized largemouth bass ponds can enhance fingerling production above that of inorganic fertilization alone by increasing fish harvest weight, reducing pH, and increasing desirable zooplankton densities. However, the higher cost of producing these fingerlings with cottonseed meal and inorganic fertilizers (US.20/1,000 fish or $4.94/kg fish) compared with inorganic fertilizers alone (.03/1,000 fish or $1.02/kg fish) and the potential consequences of low dissolved oxygen should be weighed against the gain in fish production when deciding whether to use cottonseed meal.