Current Status and Options for Biotechnologies in Aquaculture and Fisheries in Developing Countries.

Abstract

The rapid growth of aquaculture has significantly benefited from both conventional technologies and biotechnologies and it is expected that advanced biotechnologies will further help the sector in meeting the global demand for aquatic food in the coming decades. While biotechnologies are being applied in fisheries management, their use is very limited compared with aquaculture. The four main areas where biotechnologies have been used in aquaculture and fisheries include genetic improvement and control of reproduction; biosecurity and disease control; environmental management and bioremediation; and biodiversity conservation and fisheries management. One of the main reasons for the success of aquaculture is the diversity of species currently in culture (over 230) and the genetic diversity that can be exploited through captive breeding and domestication. However, the rearing of many newly cultured species is to a large extent based on juveniles and/or broodstock obtained from the wild. In order to establish practical breeding programmes to produce seed in hatcheries, it is necessary to have a detailed understanding of the complete production cycle. Such knowledge is also required to disseminate breeding improvements to the production sector. Improvements that allow the wider application of appropriate genetic and reproduction biotechnologies will undoubtedly increase aquaculture production, thus contributing to global food production. These biotechnologies include polyploidy, gynogenesis and androgenesis, the development of monosex populations and cryopreservation. Disease outbreaks are a serious constraint to aquaculture development. Disease control and health management in aquaculture are different from the terrestrial livestock sector, particularly due to the fluid environment. Disease occurs in all systems, from extensive 192 B iotech nolog i es for Ag r icu ltu ra l D eve lopm e nt SECTION 1: BACKGROUND TO to intensive, and losses are possible in all types of production systems. There is a need for better management of intensive systems, and biotechnologies are being used for this purpose. Immunoassay and DNA-based diagnostic methods are currently used to screen and/or confirm the diagnosis of many significant pathogens in aquaculture in developing countries. Also, one of the most important factors leading to reduced antibiotic use by the aquaculture sector is the availability of good prophylactic measures for diseases causing severe mortalities in cultured fish and shellfish. The use of vaccines provides good immunoprophylaxis for some of most important infectious diseases of finfish. As molecularbased vaccine production procedures rely heavily on biotechnological tools, vaccines are being produced mainly in developed countries. Reducing the environmental impacts of aquaculture is a significant task. Aquaculture is often accused of being unsustainable and not environmentally friendly. Reducing the impacts of effluent discharge, improving water quality and responsible use of water are key areas to be considered in aquaculture development. Some biotechnologies are being used to address these areas, including bioremediation for the degradation of hazardous wastes and use of DNA-based methodologies for the early detection of toxin-producing algae. In capture fisheries, the sustainable management and conservation of fisheries is a priority. Better understanding of the population structure of the fishery is therefore of paramount importance. Some biotechnologies have already been applied but there is ample scope for the greater use of biotechnologies in fisheries management worldwide. The use of molecular markers and the principles of population genetics have proved very effective for assessing the actual levels of genetic variability within single populations and for measuring the extent of differentiation between populations.