The growth rate and growth efficiency of Streptocephalus macrourus (Crustacea, Anostraca) cultured on microalgae

Abstract

Affordable biological technology for the reclamation of wastes and water of the waste streams from intensive livestock units is important in a country short of water. This study tested the concept of reclamation of waste by Streptocephalus macrourus (Crustacea: Anostraca) from the effluent of a high rate algal pond processing livestock wastes. S. macrourus showed a growth efficiency of 39% to 74% when fed optimal rations and cultured at densities between 10 and 400 1−1. The maximum daily growth rates (0.15–0.21) approximate the growth rates of cladoceran or rotifer cultures managed for maximal biomass production. S. macrourus' ability to withstand crowding enabled the production from S. macrourus cultures (up to 91.8 mg dry mass l−1 d−1, or 1241 mg wet mass l−1 d−1) to exceed production recorded from cladoceran or rotifer cultures. Temperature influenced growth rate, with the highest growth rate occurring at 24 °C. The dilution rate of continuously fed cultures influenced growth rate, with the optimum dilution rate tested being 10 ml organism −1 d−1. Mass mortality occurred when organisms were held at a density of 4000 l−1. S. macrourus is able to convert algae grown on livestock waste efficiently into anostracan biomass, and is able to give a very high daily production.