3. Alien fish species
Conveners: Gordon H. Copp,
UK (g.h.copp@cefas.co.uk)
Henn Ojaveer, Estonia (henn@sea.ee)
In approximately the
last 100 years, the propensity to translocate and introduce fish
species, both
intentionally and by accident has increased dramatically, threatening
both
freshwater, estuarine and marine environments. Marine fish transfers
have been
driven in large part by discharges of ballast water, though these
introductions
affect all aquatic ecosystems. Freshwater fish introductions,
propagated by
acclimatization and novelty organism societies (aquarists, garden
enthusiasts)
in the late 19th and early 20th centuries, have
continued, with a constantly increasing range of fish species being
translocated into new areas. Common themes of invasion biology relevant
to
marine and freshwater alien fishes are: introduction pathways and
processes
(transport vectors, survivorship during the voyage), factors associated
with
the impediment or facilitation of establishment (life-history traits,
environmental tolerances, growth and morphological plasticity during
ontogeny,
food availability, predator density), dispersal mechanisms and
processes
(migratory patterns, spawning behaviours, air-breathing capacity), and
potential ecosystem impacts (predation and/or competition on/with
native species,
reproductive interference, disease transmission, habitat degradation,
food-web
changes, flow of toxic substances).
An
understanding of the factors associated with species introductions,
their
success or failure to establish, the rates and means of dispersal, and
the
potential and realised impacts is essential to the development of risk
and
impact assessment protocols, which are important decision-making tools
for both
national and international government organisations. The aim of this
symposium
is to provide a forum for marine and freshwater ichthyologists to
compare and
contrast methodologies to the four phases of invasion biology in
various
habitats/ecosystems, including ontogenetic processes, so as to
facilitate
cross-pollination of conceptual and applied approaches.
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