Defining loading limits of static ponds for catfish aquaculture

摘要

Commercial channel catfish farming has emerged as the most important aquaculture industry in the United States. During the last two decades, industry growth has occurred by expansion in the number and area of facilities and through production intensification. Evidence suggests that catfish farming has apparently reached the limits of the production system as currently configured. The success of commercial catfish culture can be attributed in part to low production costs resulting from the inherent waste assimilation capacity of aquaculture ponds, although operating within this capacity is complex and associated with several poorly defined limitations and hidden costs. Loading limits for pond aquaculture are based on the waste assimilation capacity of ponds and tolerance limits of the cultured species. The important design and operational considerations affecting loading limits include temperature effects, oxygen requirements, fish water quality tolerance limits, organic matter decomposition, and nutrient removal. Engineering solutions for extending the loading limits of pond aquaculture must account for the highly dynamic and complex nature of the pond ecosystem, particularly processes related to phytoplankton and microbial dynamics. Characteristics of hypertrophic ponds amenable to engineering solutions include excessive phytoplankton biomass, dominance of phytoplankton communities by cyanobacteria, intense diurnal stratification, chronic undersaturation of dissolved oxygen at the sediment-water interface, and limitations of current aeration technology. Improvements in the profitability of catfish pond aquaculture requires broad-scale implementation of a production paradigm based on measures of performance efficiency.