Abstract
Because commercial aquaculture of the crayfish, Procambarus clarkii, depends mainly on a foragebased production system, management could benefit from a better understanding of the linkages between system food components and growth of crayfish. This study was designed to estimate the contribution of this production system's separable dietary components to juvenile crayfish growth and assess the system's limitations. Crayfish weight gain was determined in static-water microcosms with and without various dietary components of the forage-based production system and a prepared feed. Crayfish were held individually in 3.8-1 glass jars with water maintained at 26.5 ± 1.5 °C and supplied with supplemental aeration. Approximately 450 ml of pond soil (except where absence of soil was used as a treatment) and unfiltered pond water (except when different water sources were used as treatments) provided the basic simulated production system. Six-week weight gain data from three separate feeding trials were used to fit a multiple linear model with zero intercept to estimate contribution to growth from separable components of the system. These components were — in decreasing order of importance — prepared feed, microbially enriched detrital forage, soil benthos, soil substrate and possibly peron associated with detritus. Nitrogen and phosphorus amendments to microcosms under the conditions of this study failed to improve crayfish weight gain. Likewise, microbial biomass of detrital rice (as estimated by ATP concentration) was not affected by either addition.
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