Development of rearing methods for rare or endangered fish species

At the moment we are working on rearing methods for the minnow. Genetically conforming mother fish stocks have been established at the Kreuzstein Fish Hatchery in order to be able to breed different minnow populations. Spawning of minnows under fish culture conditions is a challenge, because they are very sensitive to stress and spawning has to be controlled and triggered by natural environmental factors. This problem could be solved as follows. Mother stocks of minnows are kept in round tanks equipped with spawning substrate. Spawning is controlled by temperature and photoperiod. Spawned eggs are collected above the pool drain. In 2016 and 2017, this method produced a total of approximately 200,000 minnows for restocking of various water bodies.

The smooth sturgeon (Acipenser nudiventris) and the European house sturgeon (Huso huso) are endangered sturgeon species with a declining population trend. Different housing densities and different feeds have been tested for rearing these fish species. The rearing of the Hausen is particularly difficult, as they have a rotating, disoriented movement towards the end of the yolk sac phase and show a non-targeted biting behaviour. This seems to be exclusively a reflex to a movement stimulus in the near environment and requires special housing and feeding conditions.