Benefits of species introductions
While recent attention has focused on the adverse impacts of introduced species - also known as alien species and alien genotypes - species introductions are a valid means to improve production and economic benefit from fisheries and aquaculture.
Consider the following:
- Approximately 17 percent of the world's finfish production is due to alien species.
- Production of the African cichlid tilapia is much higher in Asia (>700 000 metric tonnes in 1996) than in most areas of Africa (39 245 metric tonnes).
- Introduced salmonids in Chile support a thriving aquaculture industry that is responsible for approximately 20 percent of the world's farmed salmon and directly employs approximately 30 000 people.
Impacts
Introduced species may have environmental as well as social and economic impacts. Aquatic ecosystems may be affected by the introduced species through predation, competition, mixing of exotic genes, habitat modification and the introduction of pathogens. Human communities may also be impacted through change in fishing patterns due to a newly-established fishery or through changes in land use and resource access when high valued species are introduced into an area.
The practice of using species outside their natural range to increase production or profitability can be expected to continue. The issue is not to ban alien species - or to abandon regulation of their movement - but rather to assess associated risks and benefits and then, if appropriate, develop and implement a plan for their responsible use. One mechanism to assist in the responsible use of introduced species is the development of codes of practice such as have been developed by the International Council for the Exploration of the Sea and the European Inland Fishery Advisory Commission.
Legal instruments
Significant international instruments have recently been established to address the issue of species introductions, such as the Convention on Biological Diversity and the FAO Code of Conduct for Responsible Fisheries. These codes and conventions call for accurate assessments of the risks of using exotic species and are promoting the creation of information sources and an exchange of information on exotic species, their biological and ecological attributes, and potential impacts (both positive and negative). The problem is how to determine the impact of a proposed introduction into complex and dynamic aquatic ecosystems where our information base is often inadequate.
Toward this end, FAO Fisheries Department has created the Database on Introductions of Aquatic Species (DIAS) to serve as an important initial summary and registry of introduced species. This database has been incorporated into FishBase, a relational database that contains a variety of information on approximately 20 000 of the world's species of finfish.