Growth of Cherax quadricarnatus (redclaw) reared in different conditions in RAS

This study is to evaluate the growth and performance of Redclaw crayfish (Cherax quadricarinatus) in Aquahive modules and recirculating aquaculture systems to be tested at UiB climate control room 6. The crayfish will grow normally and at a stocking density that will not cause distress to the crayfish or diminish welfare. The crayfish are expected to eat and to behave normally. Rearing the crayfish in «apartments» will remove aggression and cannibalism between the animals, and ensure safe molting (ecdysis). The Aquahive system have been tested for other species of lobster and crayfish. However, Redclaw crayfish have not been tested in the system. The test will use a total of 216 crayfish (54 crayfish per tank) and grow them in the system for 7 months or until certain size. The crayfish will be weighed and measured biweekly and In order to investigate potential effect on metabolic rate and blood chemistry, haemolymph samples and respirometry tests will be conducted at a certain size. This study is designed to test a technology that could, potentially, improve welfare for aquaculture crayfish and at the same time improve the over all production of redclaw. The use of crayfish is unavoidable since this is the target of the technology and improving production. The number of crayfish used is a minimum to ensure stocking densities comparable to commercial production, as well as maintaining a sufficient study design.