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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.
- 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.
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.
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.
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