Developments in recirculating systems for Arctic char culture in North America

Arctic char (Salvelinus alpinus) tolerate high-density culture conditions, have an excellent fillet yield, are amenable to niche marketing, and are suitable for production within super-intensive recirculating systems. Much of the North American production of Arctic char has been within recirculating systems, which can provide more optimum water temperatures for fish growth and can also overcome limitations created by a lack of high-quality water resources or strict pollution discharge limits. This paper describes some of the developments that have been made in recirculating systems used to produce Arctic char and examines several North American facilities that have used recirculating systems to produce Arctic char. This description includes several state-of-the-art recirculating systems that are now being used to commercially produce Arctic char and another that has just been built and is about to come on-line. This paper also describes several areas where advances have been made in cold-water recirculating system design in order to improve the water quality that they maintain at high feed loadings and to increase the production capacity of these systems. Several critical process improvements include: increased hydraulic exchange rates through the culture tank, superior culture tank designs, better oxygen control strategies and ozonation, improved design of forced-ventilated cascade aeration columns, full flow drum filtration, and better pipe and sump cleanout designs. Several of the strengths and weaknesses of Arctic char production within land-based recirculating systems are also discussed. (C) 2003 Elsevier B.V. All rights reserved.