Risk Assessment in Ballast Water Management - Global Maritime Transport and Ballast Water Management: Issues and Solutions - page 143

In many environments (or biogeographical regions) the knowledge on the
taxonomy of indigenous organisms is defi cient, while the identifi cation of organ-
isms originating from other parts of the world is even more demanding. Consequently,
numerous organisms may remain unidentifi ed.
For a target list of unwanted organisms, fundamental selection criteria must be
defi ned. Based upon the IMO defi nition in the G7 Guidelines, at least all following
factors need to be considered (IMO 2007 ) when identifying target species:

- evidence of prior introduction, i.e., thereby the species shows its capability to

become introduced outside its native range;

- potential impact on environment, economy, human health, property or resources;

- strength and type of ecological interactions, i.e., severeness of its impact;

- current distribution within the biogeographic region and in other biogeographic

regions; and

- relationship with ballast water as a vector, i.e., when the species was already

found in a ballast tank or if the life cycle of the species include a larval phase
which makes a ballast water transport likely.

Numerous attempts were undertaken to identify typical characteristics of an
'ideal' invasive species. It was discussed that species with high environmental toler-
ances and those with high reproduction rates may have a higher invasion potential
(Safriel and Ritte 1980 , 1983 ; Kareiva 1999 ; Hewitt 2003 ).
The objective of this approach is to consider species life history information and
physiological tolerances to characterise physiological limits of a certain species
which leads to its survival potential or potential to complete its life cycle in the
recipient environment. In other words, the individual species characteristics need to
be compared with the environmental conditions in the recipient port, which results
in a determination of the likelihood of transfer and species survival.
A target species is not needed in all circumstances but may be useful to focus a
surveillance action or may be necessary for legislative compliance. The species of
concern (target species) need to be selected for a specifi c port, country, or biogeo-
graphical region. As a fi rst step to generate a target species list, all species being
potentially harmful and invasive (including cryptogenic and harmful native species)
present in the donor port(s) should be listed and, secondly, target species are to be
selected based on pre-defi ned criteria (see above).
A problem is subjectivity with the target species selection. It may occur that the
assessment whether or not a species should become a target species will result with
a degree of uncertainty associated with the approach. It is possible that species iden-
tifi ed as harmful in some environments may not be harmful in others and vice versa.
In addition to the data referred above, the following information is needed to
enable a RA using the species-specifi c approach (based on G7 Guidelines, IMO
2007 ):

- biogeographic region of donor and recipient port(s); the presence of all non-

indigenous species (including cryptogenic species) and native species in the