A bioassay for production capacity assessment

Given sufficient oxygen, fish production can be limited by a multiplicity of factors. Accurate determination of production capacity requires something other than an estimate of the biomass at which ambient un-ionized ammonia will reach a recommended, non-site-specific, maximum safe concentration. A chronic (1- to 2-month) bioassay can be used to determine the point at which metabolite buildup reduces growth by some predetermined proportion, or causes unacceptable tissue damage. The bioassay is conducted as a series reuse, single-pass system, in which incoming water to each rearing unit is aerated to 90% dissolved oxygen saturation. The assessment of production capacity is based on the relation between cumulative oxygen consumption and growth reduction.