The Transfer of Harmful Aquatic Organisms and Pathogens with Ballast Water and Their Impacts - Global Maritime Transport and Ballast Water Management: Issues and Solutions - page 50

particular form of cholera had previously been known only in Bangladesh (Casale
2002 ) thereby highlighting the likelihood that ballast water transport contributed to
this disease outbreak.
A study of ships in Hamilton and Toronto (Canada), at the entrance to the Great
Lakes of North America, conducted in 1995 found within 71 ballast water samples
a frequency of 45 % of the faecal coliform bacteria, Escherichia coli , and 80 % of
the samples contained enterococcal bacteria (Whitby et al. 1998 ). Furthermore,
streptococcal bacteria were found in four ballast water samples taken during this
Canadian study.
Future Issues and Concerns
Monitoring of ballast water receiving habitats to document newly introduced spe-
cies is rarely undertaken. Coastal monitoring programmes exist, but in many cases
they lack sampling stations in ports where the ballast water is discharged or taken
up. Only when new introduced species are recognized soon after introduction an
eradication programme is advisable, should the newly found species cause concern.
Regular monitoring using a rapid assessment approach is more likely to encounter
targeted species at an earlier time (Minchin 2007b ) so that those found at an early
stage might be eradicated (Bax 1999 ). The longer a species occurs unnoticed the
more unlikely an eradication programme will be successful, as during the interven-
ing time, the species is likely to have spread over a wider area.
The identifi cation of species is often dependent upon taxonomic skills which are
not easily acquired. It may well be possible that such services, due to the reducing
number of specialists, will become less available creating a consequent confusion in
the area of biogeography and biological invasion science. Taxonomic skills are
needed as the invasion status of an organism can normally only be assessed when the
species level is identifi ed. The lack of taxonomic expertise may also lead to overlook-
ing introduced species, as had happened with Mnemiopsis leidyi in the North Sea.
The presence of this species was possibly overlooked for almost a decade as the
comb jellies found were confused with native species (Van Ginderdeuren et al. 2012 ).
Although there is an impressively high number of new non-indigenous and/or
harmful species being introduced every day all around the world, relatively few
cases of 'successful' invasions have been recognised. Despite relatively few inva-
sions, a number of cases have had signifi cant (almost catastrophic) and seemingly
irreversible impacts. Consequently, a precautionary approach suggests that every
vessel transporting ballast water should be treated as a potential risk by enabling
introductions of harmful species.
Acknowledgements The research leading to these results has received funding from the European
Community's Seventh Framework Programme (FP7/2007-2013) under Grant Agreement No.
[266445] for the project Vectors of Change in Oceans and Seas Marine Life, Impact on Economic
Sectors (VECTORS).