Science Facing Aliens - Invasive Alien Species in Belgium - Belgian ...

Non-indigenous species of the Belgian part of the North Sea and
adjacent estuaries
VLIZ Alien Species Consortium (listed in alphabetical order)
Bauwens M. 1 , Braeckman U. 2 , Coppejans E. 2 , De Blauwe H. 3 , De Clerck, O. 2 , De
Maersschalk V. 2 , Degraer S. 2 , Deprez T. 2 , Dumoulin, E. 3 , Fockedey N. 1 , Hernandez F. 1 ,
Hostens K. 4 , Lescrauwaet A.-K. 1 , Mees J. 1 , Rappé K. 2 , Sabbe, K. 2 , Seys J. 1 ,Van
Ginderdeuren K. 1,4 , Vanaverbeke J. 2 , Vandepitte L. 1 , Vanhoorne B. 1 , Verween A. 2 ,
Wittoeck J. 4
1 Flanders Marine Institute (VLIZ)
2 Ghent University; Department of Biology
3 Belgian Coastal Study Group (SWG)
4 Flemish Government; Agriculture and Fisheries; Institute for Agricultural and Fisheries
Research; Fisheries Research Domain (ILVO)
Contact: Leen Vandepitte & Ann-Katrien Lescrauwaet
Introduction
Colonization of marine, coastal and estuarine environments by non-endemic or nonindigenous
species is not a recent phenomenon in the Belgian context. Some of our history
books contain references to early human introductions of non-endemic species, related to
aquaculture and other economic purposes. For those aquatic species, it is relatively easy to
define the year of introduction or ‘first observation’ for Belgian waters. Non-endemic species
are also often discovered by coincidence. However, for a number of species in the marine and
estuarine environment, it is difficult to say whether they are endemic or not. For some taxa it
is difficult to distinguish between local and non-endemic species, which may lead to
erroneous determinations. Our knowledge and research techniques have evolved enormously
over the last centuries, and we can not always say with certainty whether a species may have
been present before. This is particularly true for smaller and inconspicuous species such as,
e.g., bacteria, microscopic algae or species with an elusive behavior. We refer to those species
as ‘cryptogenic’.
Once non-endemic or ‘alien’ species have settled as reproductive populations, it is
difficult to turn back the clock. Aliens may cause impact of differing type and degree in their
new environments. This impact can cause damage to economy, public health and biodiversity.
In this case, the alien invaders are catalogued as ‘invasive’ species. Directed management
efforts may mitigate or reduce the damage caused by non-endemic species, or even anticipate
them. It is therefore important to collect data on these particular species, their location and
changes in their distribution, and the type of impact they may cause. These factual data -
together with knowledge on the species’ ecology - provides relevant information to policy and
management.
Flanders Marine Institute and its consortium of experts on non-indigenous species
(‘VLIZ Alien Species Consortium’) conduct an ongoing effort to collect and maintain a list of
aliens with documented established populations in the Belgian part of the North Sea and its
adjacent estuaries.
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