The following is provided for the guidance of port State
authorities in the implementation of their ballast water management
programme and to assess risks in relation to the ballast water containing
harmful aquatic organisms and pathogens.
10.1
Highly disparate conditions
between uptake and discharge ports
Significantly different conditions may exist between port(s)
of origin and the port in which ballast water is discharged. Examples
include freshwater ballast being released into highly saline ports.
There may be organisms capable of surviving such extreme transfers;
however, there is a lower probability of species establishment under
such transport events.
The length of time during which ballast water is within
an enclosed ballast tank may also be a factor in determining the number
of surviving organisms, because of the absence of light, decreasing
nutrients and oxygen, changes of salinity and other factors. However,
the maximum length of survival of organisms in ballast water varies,
and in many cases is not known. Water of an age of 100 days should
be considered the minimum for applying this consideration. Ballast
water and sediments may contain dinoflagellate cysts and other organisms
capable of surviving for a much longer length of time.
10.3
Presence of target organisms
10.3.1 Under certain circumstances it may be possible
to determine if one or more target species are present in the water
of a specific port and have been ballasted in a ship. In these circumstances,
the receiving port State authority may invoke management measures
accordingly. Even if such target species are not present, however,
it should be noted that the ship may still be carrying many untargetted
species which, if released in new waters, could be potentially harmful.
10.3.2 Port States are encouraged to carry out
biological baseline surveys in their ports and to disseminate the
results of their investigations.