Environmental Engineering Reference
In-Depth Information
2007). The risks posed by the accidental or intentional release of non-native aquar-
ium fi sh have been recognized in recent decades and many countries have enacted
legislation to control the importation and trade in non-indigenous ornamental
fi shes. Examples are the Import of Live Fish Act 1980 and more recently The
Prohibition of Keeping or Release of Live Fish (Specifi ed Species) (Amendment)
(England) Order, 2003, in the UK. Many countries ban the importation of species
recognized as potentially invasive and the live release or keeping of high-risk or
environmentally destructive species. Unfortunately, legislative controls are often
ineffective at limiting the distribution and release of noxious species. Despite the
listing of the alga
Caulerpa taxifolia
as an illegal noxious species by both Federal
and California State authorities, it is still widely sold by aquarium stores in the state
(Padilla and Williams 2004)
Markets selling live fi sh for human consumption, either imported or caught
locally, also pose a risk for accidental or intentional release. While biosecurity and
import legislation should eff ectively limit the risks posed by live fi sh importations,
few regulatory restrictions may exist on the sale of live exotic fi sh that are already
naturalized, unless those species are declared noxious, thereby banning their live
possession or sale (Rixon
et al
. 2005). Weigle
et al
. (2005) assessed the risks of live
release of imported marine and estuarine species associated with seven diff erent
importation and transfer industries: seafood companies; aquaculture operations;
bait shops; aquarium shops; research and educational organizations; public aquar-
iums; and coastal restoration projects. h e risks for each activity contrasted strongly
between the diversity of taxa imported (high for public aquaria and the aquarium/
ornamental trade) and the number of individuals imported (many individuals
from few taxa in the case of the seafood and live bait industries). h e importation
of imported live bait is clearly high risk given that the release of these organisms
into the environment is virtually certain. Given the diversity of non-indigenous
marine taxa typically stocked in public aquaria, this industry also poses signifi cant
risks of release since most large public aquaria use local coastal seawater supply.
Unless e
uent water is carefully treated or fi ltered, non-indigenous fi sh larvae or
propagules of other organisms may be released. For instance, the aggressive inva-
sion of the Mediterranean Sea by the alga
Caulerpa taxifolia
since the mid 1980s
probably originated from the Aquarium of Monaco (Jousson
et al
. 1998).
h e risks posed by the domestic ornamental and aquarium trade vary consid-
erably based on the key taxa traded and the locality of sale. Given that the vast
majority of aquarium fi sh species are of tropical origin, their survival, and cer-
tainly reproduction, in temperate latitudes is unlikely unless local peculiarities in
water temperature allow. For example, three tropical aquarium species have been
recorded as establishing breeding populations in New Zealand but are restricted
to geothermally-heated locations in the central North Island (McDowall 1990).
However, aquarium releases pose signifi cantly greater threat in tropical and sub-
tropical regions and have been identifi ed as the prime culprit in the observed
diversity of non-native marine species in south-eastern Florida. Sixteen non-
indigenous marine species have been recorded, and their concentration close to
