Risk Assessment in Ballast Water Management - Global Maritime Transport and Ballast Water Management: Issues and Solutions - page 142

Species' Biogeographical Risk Assessment
The species' biogeographical RA compares the distribution of non-indigenous,
cryptogenic, and harmful native species presently occurring in the donor and recipi-
ent ports and biogeographic regions. Should species occurrences overlap in the
donor and recipient ports and regions this is a direct indication of environmental
similarity to enable a shared fauna and fl ora. The biogeographical approach may
also be used to identify high risk species (see also the species-specifi c approach). As
an example, harmful species in the ballast water donor biogeographic region which
are known to have successfully invaded other (similar) biogeographic regions, but
are not (yet) found in the recipient biogeographic region of the RA, could be con-
sidered as high risk species for the ballast water recipient region. As a general rule,
the higher the number of biogeographic regions in which such species have invaded,
the greater is the potential that those species would also be able to become estab-
lished in the recipient port or biogeographic region. Another general risk indicator
is given in case where the donor biogeographic region is a major source of species
to other areas.
The data requirements (IMO 2007 ) to enable a species biogeographical approach
RA include:
1. species invasion records in the donor and recipient biogeographic regions and
ports;
2. records of native or non-indigenous species in the donor biogeographic region
which may be transferred with ballast water and which have already invaded
other biogeographic regions and the number and characteristics of these invaded
biogeographic regions;
3. records of native species in the ballast water donor region which have the poten-
tial to affect human health or to cause substantial negative ecological or eco-
nomic impacts after introduction to the ballast water recipient region.
The species' biogeographical RA may also be used to identify potential target
species (see below) in the donor region(s). Criteria to identify such species include
native species with a wide biogeographical or habitat distribution or species which
are known as invaders in other biogeographic regions, which are similar to that of
the ballast water recipient port.
Species-Specifi c Risk Identifi cation
The identifi cation of species-related risk focuses on the evaluation of the potential
invasiveness of each selected species considering also the harm that it could cause
in the new environment. Today we lack data and have insuffi cient knowledge con-
cerning the invasiveness of organisms with some key questions remaining un-
answered, e.g., What predicts invasiveness in a new environment? How does the
degree of species tolerance regarding environmental conditions, food availability,
reproduction behaviour and capabilities infl uence invasion success? How can we
anticipate the harm that could be caused?