It has long been recognised that ballast water represents the primary vector for the introduction of invasive aquatic organisms into waterways and coastal ecosystems. Invasive species threaten not just the balance of the ecosystems themselves but may also degrade coastal and inland fisheries, through encroachment by non-commercial species, and hamper industrial and municipal water usage, through the clogging of intakes by species such as zebra mussels. Studies suggest that the economic cost just from introduction of pest molluscs such as zebra mussels to U.S. aquatic ecosystems is more than $6 billion per year. Introductions of some species through this vector can involve potentially serious health risks. In 1991, ballast water containing the microbe Vibrio cholera was released and infected the drinking water in Peru. One million people were infected with cholera and more than 10, 000 died. Also, prominent has been the proliferation of harmful algal blooms, resulting from ballast water transport of phytoplankt on between coastal areas. Depending on the species, these blooms can cause massive kills of aquatic life through oxygen depletion and release of toxins.
The transoceanic transport of non-indigenous species was the focus of the 2004 United Nations International Maritime Organization (IMO) International Convention for the Control and Management of Ships’ Ballast Water and Sediments (BWMC) mandating international ballast water management.
As the BWMC advances towards full ratification by IMO member states (alongside development of USCG rules) and with its entry into force exactly 12 months following full ratification, the size and scope of the management task become increasingly clear. The worldwide commercial fleet has been estimated at approximately 70, 000 vessels. Ballast capacities range from several cubic meters in the case of fishing boats, to hundreds of thousands of tonnes on very large bulk carriers. The majority of these vessels will require some kind of Ballast Water Management plan in place and most likely some kind of treatment system.
However, once the convention has been ratified the communities attention will likely be focussed on compliance. This includes developments in sampling and monitoring and enforcement. The complexity of the issue and the need for a relatively uniform approach to this worldwide challenge will require a sustained effort to standardise outstanding sampling and analytical protocols, develop innovative monitoring technologies and streamline the testing process. All ship owners will have to comply with the upcoming BWM regulations. Whilst ship owners need to begin planning immediately for the installation of treatment systems and selecting safe, practical, robust and reliable ballast water management solutions, the maritime technology sector has a unique opportunity to move into a new market with monitoring and sampling for compliance going to be significant relevance to enforcement agencies (in most cases port state control) globally.
It is critical that cost-effective means for enforcing the BWMC are developed. Only then are we likely to see a slowing of the worldwide exponential increase in aquatic invasive species introduction.
(sourc: Oeceanology International Team via Ocensp@ce)