Eno., N.C., Clark, R.A. & Sanderson, W.G. (Edited by)
The study reported here was undertaken to collate details and review information about introductions of marine fauna and flora to Great Britain (England, Scotland and Wales). The focus of this review is on nature conservation and the work will be used to formulate policy on marine introductions in relation to nature conservation interests.
The study reported here was undertaken to collate details and
review information about introductions of marine fauna and flora to
Great Britain (England, Scotland and Wales). The focus of this
review is on nature conservation and the work will be used to
formulate policy on marine introductions in relation to nature
conservation interests.
The study evaluates non-native macro fauna and flora, which
have been introduced from outside their natural range and have
become established in the wild in British waters. This report
evaluates their origin, date and method of introduction, the
reasons for their success, rate of spread, current distribution,
actual and potential effects on native ecosystems and nature
conservation as well as commercial interests, and methods of
control. Micro-organisms (< 20 µm) are not considered.
Fourteen species of marine alga (or 15 taxa including two
subspecies of a single species of green alga), five diatoms, one
angiosperm and 30 invertebrates have been identified as non-native
and aspects of their introduction and subsequent effects described.
The majority of these 50 species are red algae, polychaete worms,
crustaceans and molluscs. No non-native sponges, bryozoans or
echinoderms have been found in British waters. Although the
frequency with which introduced species have been recorded in
Europe has increased with time, there is no trend in the number of
non-natives which have become established in Britain. Species have
been introduced directly from primary sources or areas within their
natural range or from secondary sources to which they had
previously been introduced. In general, species were found to have
only become established if they were introduced from similar
latitudes of either hemisphere. More than half the total number of
species described here are considered to have been introduced to
Britain in association with shipping, whilst half of the non-native
marine algae found in Britain are believed to have been introduced
to Europe in association with deliberate introductions of shellfish
for mariculture.
Of the species deliberately introduced for aquaculture, only
some of the bivalve molluscs have become established in the natural
environment beyond the confines of their cultivation.
The success of the non-natives described here has, where
known, been due to a combination of reasons. Of the species that
have spread, the marine algae did so fairly rapidly, while the
invertebrates tended to spread more slowly. The method of spread,
e.g. in association with shipping, was often the same as their
method of introduction for both fauna and flora.
The direct effects of non-native species on the marine environment
in British waters are in general not as detrimental as reported
from elsewhere in the world. Commercially, some economically
important species have been introduced, but some associated pests
and parasites adversely affecting native species have also been
unintentionally introduced. Control methods, where applied to
nuisance species, are fairly ineffective and no non-native marine
species have yet been successfully eradicated from British waters.
The different aspects of the biology and etiology of non-natives
are discussed in relation to determining their presence and
monitoring their distribution, and developing ways of avoiding
further introductions.
Please cite as: Eno., N.C., Clark, R.A. & Sanderson, W.G. (Edited by), (1997), Non-native marine species in British waters: a review and directory, 152 pages A4 softback, ISBN 1 86107 442 5