AStRa - Astacus stock raise
Subject of the project AStRa is the development of a recirculating aquaculture system (RAS) to produce noble crayfish (Astacus astacus). This decapod crustacean, that resembles a small lobster, was previously a wide-spread species in German rivers and lakes. Now, this species is on the national Red List in Category 1 – threatened with regional extinction. Causes for the decline are pollution, hydraulic constructions, poaching and, first and foremost, the introduction of an invasive crayfish species, the spiny-cheek crayfish (Orconectes limosus) from America, accompanied by a fungus-like water mold, the crayfish plague (Aphanomyces astaci). This disease is fatal to the noble crayfish whereas the introduced spiny-cheek crayfish, that is carrier of Aphanomyces astaci, has co-evolved a high degree of immunity against this pathogen. Since the noble crayfish is a high value food product, a successful stock enhancement and repatriation of the species would have both, an environmental and an economic benefit.
For a reliable reproduction of large quantities of noble crayfish a RAS could offer pathogen-free and controllable conditions of water temperature, oxygen saturation, pH, et cetera. In contrast, environmental conditions cannot be easily controlled in open pond systems that are exposed to the uncertainties of the weather and that are seriously threatened by an epidemic of the crayfish plague. However, until now, the requirements for a reproduction and intensive culture of noble crayfish in RAS are poorly understood, especially aggressive behaviour and cannibalism of crayfish kept at high stocking densities restrict the culture of this species. Therefore, the aim of the A.st.ra project is to optimize the reproduction, nursery, and grow-out of noble crayfish by conducting a series of experiments on habitat design, stocking density, water treatment, water flux, and feeding. The results will be compared with those from similar experiments in pond systems. The project will be accomplished in close collaboration with our private and public project partners: Forellen- und Edelkrebszucht Poggenhagen, the University Koblenz-Landau, the Alfred-Wegener-Institute for Polar- and Marine Research (AWI), and Krebssucht am Schloß.
The project is open for bachelor, project and master theses. Read here for more information.