New aquaculture facility for best husbandry conditions

Aquaculture recirculation systems are used for the production of fish and other aquatic organisms for consumption. They constitute a new, future-oriented technology that combines high water quality with a small ecological footprint and is intended to supplement or replace conventional forms of production (net pens, flow-through systems).

Innovative technology also for Switzerland

Recirculating aquaculture systems are extremely economical in water consumption, allow optimal conditions for the animals and cause minimal emissions. This makes them an attractive and future-oriented source of income, both for farmers and for large companies. ZHAW experts are therefore working closely with Swiss industry to promote the use of this technology. Several large aquaculture companies, such as Basis57 nachhaltige Wassernutzung AG, Swiss Alpine Fish AG or Edelkrebs AG, receive support, but so do operators of small, decentralized systems with a low ecological footprint.

Recirculating systems conserve resources

The facility at the ZHAW in Wädenswil holds 50 cubic meters of water and consists of three man-deep basins and a sophisticated water treatment system. Currently, salmon swim in these basins, which have integrated temperature control. This also makes it possible to keep egli, zander, trout or tilapia. "The water in the basins, which is polluted by fish excretions, is filtered through several stages, sterilized and enriched with oxygen before it flows back into the fish tanks" explains Mathias Sigrist, the scientific assistant responsible for the ZHAW facility. "During this process, the water quality is continuously monitored in an automated manner, and a heat pump ensures that the water temperature is appropriate for the species. The constant cleaning enables extremely economical water consumption, which at 500 liters of water per kilogram of fish produced, is up to a hundred times lower than that of a conventional flow-through system."

A true data octopus

The plant is equipped with a wide variety of sensors that provide a large number of measured values every minute. With this data, performance and energy requirements can be closely monitored. In the next research project, this should make it possible to optimize recirculating systems in terms of energy while at the same time offering the fish the best possible conditions. The aim is to operate the plant in such a way that its energy requirements are adapted in advance to the supply of renewable energy. For example, an algorithm can decide that more feeding is allowed today because tomorrow is a sunny day when enough solar power will be available for water purification. This will allow recirculating systems to be operated even more sustainably in the future.

Know-how to breed fish

Fish farms bear responsibility. For this reason, the ZHAW has been offering the specialized non-professional training course (FBA) Aquaculture since 2011. In this six-day course followed by a three-month internship, commercial breeders of fish and armored crabs are trained. More than 120 people have already completed this training. Knowledge of animal behavior and animal health, but also economic and technical aspects and requirements of animal welfare legislation are taught.