"States should conserve genetic diversity and maintain integrity of aquatic communities and ecosystems by appropriate management. In particular, efforts should be undertaken to minimize the harmful effects of introducing non-native species or genetically altered stocks used for aquaculture including culture-based fisheries into waters, especially where there is a significant potential for the spread of such non-native species or genetically altered stocks into waters under the jurisdiction of other States as well as waters under the jurisdiction of the State of origin. States should, whenever possible, promote steps to minimize adverse genetic, disease and other effects of escaped farmed fish on wild stocks."
(CCRF Article 9.3.1)
Maintaining genetic diversity by management. Aquaculture practices can affect genetic diversity at the species, community, ecosystem and landscape levels. In fact aquaculture is designed to change the landscape or ecosystem to one that is more productive. Management to protect aquatic genetic resources involves risk assessment and monitoring (Ref. 75), as laid out before, and should involve documentation of "wild" genetic resources to establish a benchmark for assessing impact. Efforts should be made to document the genetic resources utilized in aquaculture as well as to compile information on natural aquatic genetic resources. Information bases may need to be established on aquatic genetic resources and their distribution, including both farmed and wild aquatic species. Further, aquaculture stocks or stocks for culture-based fisheries can be managed within the culture facility:
Natural levels of genetic diversity can be maintained by reducing the movement of genetically diverse populations within a country. That is, egg/fingerling/adult transfers among river basins or large water bodies should be avoided if possible. Hatcheries have a history of egg transfers over large distances and there is evidence that many of these transfers do not perform as well as local stocks when released into the new environment. This is most important in culture-based fisheries. In contained growing situations the mixing of genetically diverse stocks often leads to improved culture performance. However, in the case of inter-specific hybrids, the improvement may only be found in the first generation cross and not in subsequent breeding of the hybrid population.
Genetic technologies can also be used to reduce the risk of the genetic impacts of farmed stocks on wild stocks. For example, culture of non-reproductive animals (e.g. sterile, triploid or mono-sex populations of organisms) will reduce the chance of the organism breeding in the wild. Public education on the safety and ethics of genetic technologies may be required to ensure consumer acceptance of aquaculture products.
Native species are often promoted as an alternative to introducing exotic species for aquaculture development. Often exotic species are preferable from an economic point of view (i.e. better price, export potential, etc.) and local species may not be domesticated. Native species may be preferred locally, may have less chance of introducing disease, and may grow better under local conditions. However, native species taken from the wild and domesticated or subjected to other genetic modifications may also pose a risk to the remaining wild stocks, both from genetic and disease standpoints.
Box 8. Several mechanisms exist to regulate the use of genetically modified organisms and introduced species in aquaculture. For introduced species the ICES/EIFAC Code of Practice (Ref. 76, 77), the Nuisance Species Protection Act (USA; Ref. 78) as well as national legislation in many countries govern the use and transport of species outside of their natural range. For genetically modified organisms (GMOs), the Directives of the European Union (Ref. 79), Performance Standards of the USDA (Ref. 80) as well as the ICES Code of Practice govern their use, transport, and release into the environment. The Convention on Biological Diversity is mandated to draft biosafety protocols for the safe use of genetically modified organisms (primarily plants at this stage), and until such protocols are negotiated, UNEP International Technical Guidelines for Safety in Biotechnology have been recommended by the Convention's Conference of the Parties (Ref. 81).
Databases on international introductions of aquatic animals
(Ref. 82) and aquatic animal pathogens (Ref. 83) are sources of
information that can be consulted to help determine what risks a proposed
introduction may entail. These databases are continuously being updated and
(CCRF Article 9.3.2)
International codes of practice and procedures. Several international codes of practice concerning the use of introduced species and genetically modified organisms exist and have been adopted in various forms by the international community. These codes represent one of the best means to protect the aquatic environment and their associated human communities. These codes of practice have been produced in developed countries of temperate latitudes. There is a need to adapt these to the developing and rural areas of the world. Basic elements of codes of practice such as ICES include:
Once an introduction has been approved governments should request aquaculturists to:
A country's ability to carry out the elements of the code will depend on the state of knowledge, on its human and aquatic communities and on the financial and human resources available. Faunistic and floristic surveys of local aquatic ecosystems can help determine what local species may be affected by aquaculture development and what local species may be utilized instead of importing an exotic species. Socio-economic information on the fishing sector and on the fish-consumers will also help identify those people benefiting or at risk from aquaculture development. In addition, marketing surveys can help determine the cost-effectiveness and target consumer for a proposed introduction.
"States should, in order to minimize risks of disease transfer and other adverse effects on wild and cultured stocks, encourage adoption of appropriate practices in the genetic improvement of broodstocks, the introduction of non-native species, and in the production, sale and transport of eggs, larvae or fry, broodstock or other live materials. States should facilitate the preparation and implementation of appropriate national codes of practice and procedures to this effect."
(CCRF Article 9.3.3)
Guaranteeing quality, performance and ecological safety of seed and broodstock. States and their aquaculture authorities should promote responsible practice in the genetic improvement of broodstocks, and in the production, sale and transport of eggs, larvae or fry, broodstock or other live materials. Sound hatchery practices are needed to avoid deformities or other genetic problems resulting from excessive inbreeding while allowing genetic improvement. They also are essential to minimize the spread of diseases (Ref. 84, 85, 86). Where wild seed stock is collected and distributed, particular care is required to ensure that other species are not mixed with the desired stock. (Ref. 87). States should develop guidelines or regulations, as appropriate, on what are acceptable genetic technologies and breeding practices. For example, some States prohibit the unauthorized hybridization between species; many States restrict the production of trans-genic organisms, whereas some impose strict regulations on the hatchery and culture facilities that are raising trans-genics (Ref. 88). The international codes of practice mentioned above may provide a framework for the development of national guidelines and procedures. As stated before, States should regulate the use and transport of aquacultured species within their borders.
"States should promote the use of appropriate procedures for the selection of broodstock and the production of eggs, larvae and fry."
(CCRF Article 9.3.4)
Selection of broodstock. Selection of broodstock should be based on, inter alia, the performance of the fish in culture, the desired breeding programme, the genetic profile of the broodstock, and economic and environmental considerations. Production of eggs, larvae and fry will depend upon sound hatchery and growout management, after selection of appropriate broodstock.
Breeding and genetic improvement. While considerable improvements have been made in cultured stocks through genetic selection and breeding programmes, few fish farmers have the required training and experience to do such work efficiently and without significant losses of genetic fitness. For such reasons it is advisable to establish specialized facilities for the development of improved stocks and the production of seed. Where this is not practicable, farmers should try to keep genetic diversity high (Ref. 89):
Decreased hatchability, decreased fertility, increased deformities, increased disease and decreased survival may be signs of inbreeding and loss of genetic diversity. They may be signs of other problems as well and this is why good records are necessary to determine the most probable cause(s) of the problem. Where feasible, States should also require that breeding history and disease history be maintained for aquaculture stocks. This will facilitate exchange of broodstock and seed within the country and will provide valuable information to be considered if a species is to be exported.
"States should, where appropriate, promote research and, when feasible, the development of culture techniques for endangered species to protect, rehabilitate and enhance their stocks, taking into account the critical need to conserve genetic diversity of endangered species."
(CCRF Article 9.3.5)
Safeguarding endangered species. Aquaculture practices may contribute to the protection and enhancement of stocks of endangered species. States should carefully consider the provision of support to the development of appropriate culture techniques for endangered species. The use of hatcheries and aquaculture facilities for the temporary protection and breeding of endangered species is considered to be a valuable facet of ex situ conservation. While such ex situ conservation is often necessary in the face of immediate environmental threat and the potential loss of valuable species or genetic resources, the preferred method for endangered species protection is in situ, i.e. habitat rehabilitation and the amelioration of the threat to the species.
Breeding of endangered species. The purpose of an endangered species breeding programme is to produce an organism that can be released into nature once the threat to its survival has been alleviated (Ref. 90). Breeding efforts should try to optimize the natural genetic variability in the species:
Genetic technologies can be utilized:
Where feasible and known, species that are in imminent danger of becoming endangered should be studied and managed to reduce the threat in their natural habitat. As a safeguard, sperm or live individuals could be conserved ex situ while management efforts to improve their chances of survival in nature are underway. The collection of species for this ex situ conservation should not threaten the viability of the natural population.