About Us - environmental control technologies
intro | market | health | environmental control
The beneficial use of environmental control technologies
Aquaculture systems are very diverse, and encompass practices where there is virtually no control over the environment, other than to retain fish within a specific place, to high-technology systems where almost every aspect of the environment is controlled. However, by definition, aquaculture always involves some manipulation of the environment, not least through the provision of feed, or the introduction of new stock. The control of water quantity and quality however, is mostly a feature of more intensive systems which use higher stocking densities.
Self-cleaning drum filter at salmon hatchery
Interventions to improve water quality are often required to improve conditions for the culture stock or for maintenance of environmental standards at locations where fish farms discharge. Such interventions can take the form of fairly natural treatment such as sedimentation ponds and reed beds, or can be highly technological such as the use of self-cleaning screen filters and sterilisation equipment. Such treatment systems also allow for the reuse of water so as to reduce overall demand, or increase production per unit of water resource used.
Recycle systems normally employ a high level of water re-use and often a significant amount of water treatment equipment. The benefits are seen in terms of maintaining a more constant optimum environment for the fish stock (including temperature), minimising direct environmental impacts and potentially isolating the production system from water-borne disease agents that might otherwise threaten the health of the stock. From a production point of view, such systems can shorten production cycles, reduce losses, and open up possibilities for more constant production better tailored to meeting market requirements.
Biological filters are at the heart of most recycle systems
and correct management is critical
The main constraints to greater adoption of recycle systems are often expressed as concerns over system reliability (mechanical failure can lead to faster and more catastrophic losses, or disease agents may spread more rapidly once introduced) and economics (capital costs are usually greater than for equivalent flow-through systems, and operating costs can also be higher). In both cases, the situation is gradually improving, as understanding of recycle system design and management gets better, and new materials and production techniques (as well as volume considerations) reduce costs. Recycle systems are now in widespread use for hatcheries and nursery production, and for some fish species such as eel and African catfish.
Reed bed used for effluent treatment at a trout farm in Poland
The Aquaculture Innovation Network is fostering further initiatives and adoption of environmental control technologies through an international training course in Hungary in September 2005 and during study visits to Norway (August 2005) and Germany (November 2005). Further resources are being posed on this website, and companies and organisations are invited to exchange information on products, technologies, research needs or findings and trade initiatives via the partnering and knowledge base sections.
