Environmental Engineering Reference
In-Depth Information
13
Management of invasive fi sh
Nicholas Ling
13.1 Introduction
Current understanding of the biology of fi sh invasions and the development of
statistical tools for their prevention lags well behind comparable knowledge for
other taxonomic groups such as birds and plants (Veltman et al . 1996; Goodwin
et al . 1999). A recent analysis of fi sh introductions in Europe (Garcia-Berthou
et al . 2005) warns that the probability of introduced fi sh becoming established
far exceeds that proposed for other taxonomic groups, such as the 'tens' rule of
Williamson and Fitter (1996b).
h e introduction, establishment, and spread of invasive fi sh typically follows the
same patterns as for other invasive organisms. Organisms must fi rst be transported
across a natural dispersal barrier—accidentally or deliberately—to an area outside
their native range, and then released into a suitable habitat to allow establishment
and spread. Successful introduction relies on surviving transport and subsequently
establishing a viable self-sustaining population. Whether a non-indigenous fi sh spe-
cies eventually becomes invasive depends on many factors, including the time since
fi rst release, interactions with existing indigenous and non-indigenous species, and
perceived benefi ts of the species to humans. Depending on species, invasive fi shes
may damage indigenous biodiversity (Witte et al . 2000), alter food web struc-
ture (Simon and Townsend 2003), aff ect sports and commercial fi sheries (Pycha
1980), degrade habitat quality through sediment resuspension and eutrophication
(Zambrano et al . 2001), increase stream bank erosion (King 1995), and even cause
physical injury to human water users (USGS 2004). However, unlike many organ-
isms, fi sh are far less likely to be introduced accidentally. Because most fi sh species
are reliant on continuous water immersion and relatively high water oxygen satur-
ation, fi sh transportation can be di cult. Fish are very unlikely to be introduced as
accidental stowaways in cargo, and the speed and reduced fouling of modern ships
means fi sh are unlikely to be transported outside the hull, although they may be
entrained within structurally complex hull structures, such as sea-chests, or slow-
moving towed structures such as oil platforms (Foster and Willan 1979). Most fi sh
introductions are deliberate and often based on beliefs of the economic, sporting,
or aesthetic benefi ts they will aff ord. In some cases the perceived economic benefi ts
 
 
 
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