Ballast and Unballast Operations in Oil Tankers: Planktonic Organisms That can Travel With the Ballast Water

Abstract

At the beginning of the 20th century, the presence of non autochthonous species in ballast water was admitted. However, it was not until the decade of the 70s that it was considered a problem, for more non autochthonous species all over the world were introduced and watched during the decade of 80s. Canada and Australia, two of the countries which suffered from this kind of problem, exposed their worries to the Marine Environment Protection Commitee (MEPC) at the end of that decade.
In February 2004 the IMO adopted the International Convention for the Control and Management of Ships’ Ballast Water and Sediments, which would be compulsory to fulfilling the approved standards between 2009 and 2016. Such standards comprise the year of construction of dead weight tank ship and the capacity of their ballast tanks.
Between July and December 2002, tests were carried out in an oceanic station (28° 30 ́ N and 16° 06 ́ W), with vertical tows of 50 meters long until surface, to register taxons present of the mesozooplanktonic community. The findings show average values of 313.06 density ind./m3. With regard to the percentage composition by taxonomic groups and for the same bathymetry, it stands out the community of copepods with an average value of 64.33%, followed by eggs of invertebrates and fish (18.32%), and appendicularians (5.86%). On the other hand, the remaining groups under study did not surpass the 2% of stocking.