A CULTURE SYSTEM FOR FAIRY SHRIMPS (CRUSTACEA, ANOSTRACA)

A laboratory system for the semi-automatic culture of fairy shrimps is described and evaluated. The design is directed towards an automation of both the algal food culture and the feeding of the organisms themselves. The fairy shrimps are reared in conical tanks, equipped with a recirculation system consisting of a sand filter. Deposited cysts are collected in a separate compartment, which is easily removed for further processing of the harvest. Streptocephalus proboscideus, a subtropical species, was reared at an initial density of 56 animals/litre. Several physico-chemical and biological variables were monitored at regular intervals and compared to the results derived from a static/renewal system with an initial density of 30 individuals/litre and with discontinuous food supply. The present recirculation system proved to be a reliable technique in maintaining good rearing conditions, assuring low mortality rates (+/- 5% per week) and a high cyst production (+/- 200 cysts per brood cycle) in the experimental fairy shrimp population (sex ratio 1/1), opening possibilities for several types of applications in aquaculture and aquatic toxicology. Total production yielded an average of 18 000 cysts per day and per culture unit (volume: 61).