Aquaculture & Fisheries

Biography

Biography: Niels O G Jørgensen

Abstract

Geosmin and 2-methylisoborneol (MIB) are common taste-and-odour compounds (TOCs) in many freshwater aquaculture systems especially when water recirculation is applied. The earthy and mildewed off-flavours may spoil fish stocks in both recirculated tank systems and in open fishponds. In this presentation, status on composition, occurrence and production of TOCs in trout breeding in recirculated systems is given. Also, procedures for reduction of TOCs in water and fish are presented. A major source of TOCs is Cyanobacteria (also known as blue-green algae) but recent studies indicate that various groups of non-photosynthetic microbes, especially filamentous bacteria belonging to the Streptomyces genus as well as other genera of bacteria, also contribute TOCs in recirculated aquaculture systems. Despite studies on biology and physiology of many potential TOC-producing organisms there is a limited knowledge on mechanisms that stimulate and control the production of TOCs in tanks and ponds. However, new molecular approaches appear to have a large potential for identification of dominant TOC-producing microorganisms. Further, a recently developed technique for quantification of TOCs (small stir bars with absorbing material) allows for detection of TOCs at small-scale resolution and help identification of TOC-producing hot-spots in aquaculture systems. These new developments are important tools in mitigating of TOC problems and may ensure that fish from aquaculture breeding remains attractive to consumers.