Displaying items by tag: RAS

Advantages and risks of land-based fish production

This article was featured in Eurofish Magazine 5 2021

Until now, recirculating aquaculture systems (RAS) have mostly been used to produce freshwater fish species such as eel, African catfish, tilapia, zander or sturgeon. Now, however, an increasing number of projects for land-based RAS that are designed for marine fish are emerging. For salmon alone, the planned capacity is over half a million tonnes. Investors are fuelling this development, but are their profit expectations actually justified?

A Danish company has developed a system based on analysing data collected from 12 locations on a fish farm to improve water quality and fish welfare while reducing costs. Blue Unit, a company founded by David Owen, a biologist, in 2009, was established to optimise the operations of recirculation aquaculture systems by exploiting the data available from the RAS. A centralised monitoring system collects data on 13 water quality parameters, including pH, oxygen and carbon dioxide levels, opacity, and salinity, that are monitored by specially designed sensors and compares the numbers with benchmark values from producers around the world.

Progress must be better conveyed

From simple earth ponds to offshore net enclosures and computer-controlled RAS: no other area of food production has changed so rapidly in such a short time as aquaculture. The pace of development is overwhelming for many consumers and outside the industry there are enormous gaps in knowledge which often leads to misunderstandings and even raises fears. More explanation and elucidation will be necessary to enable a constructive dialogue.

The term aquaculture has had some quite different meanings throughout history. It first appeared in 1855 in a newspaper article in connection with the storage of ice for cooling purposes in the summer months, and later on it was also used for irrigation practices in agriculture. Since the end of the 19th century (around 1890), however, it has increasingly been understood as a collective term for the methods used for the cultivation of aquatic plants and the rearing of various aquatic animal species. These mainly include fish, molluscs and crustaceans, but also aquatic reptiles, amphibians and some invertebrates, including echinoderms such as sea cucumbers or sea urchins. To be successful, aquaculture requires precise knowledge about the biology of the organisms produced, their food requirements, and their daily needs. In contrast to capture fisheries, which exploit fish stocks as a common pool resource, the plants and animals produced in aquaculture are the property of the producer or company.

This article was featured in the EUROFISH Magazine 6/2019.

An improved range of starter feeds for trout has been created following extensive research that provide key nutrients while improving water quality. Alltech Coppens TOP fry feed has an optimised ratio between digestible protein and digestible energy. This results in better performance with higher protein utilisation and lower ammonia excretion, leading to improved feed efficiency and better water quality. Dr Philip Lyons, Global Aquaculture Research Manager at Alltech Coppens says the feed not only improves performance during a critical phase but does so sustainably.