The
biodiversity threat
The introduction of invasive aquatic species (IAS) associated with global shipping has been identified as a significant threat to the world’s oceans and coastal ecosystems. A multitude of species, carried either in vessels’ ballast water or on vessels’ hulls, are capable of surviving transit to new environments where they may become invasive by multiplying and out-competing native species. Not all species transported by vessels will become invasive, and not all survive the journey. However, it is difficult to predict which species may arrive and where and when an introduced species will start to spread by itself into new areas and damage the local ecosystem. Even species that originally do not seem harmful may become invasive if environmental conditions such as temperature and nutrients change. Management practices that prevent the introduction of IAS are therefore a far more efficient and cost-effective approach to the problem than clean- ups once an invasive species has established in a new area.
While the risk posed by IAS in vessels’ ballast water is now regulated internationally under the IMO Ballast Water Management Convention, the control of vessel biofouling remains largely voluntary. As a result, individual governments develop their own strategies and policies to reduce the introduction of foreign species from bio fouling of vessels’ hull. The most comprehensive biofouling management policies to date are those of New Zealand and the US State of California – and now they will be joined by Australia.
An underestimated cost for vessel operators and the environment?
Biofouling growth on vessels’ hulls is not only a threat to marine biodiversity but also a long- standing operational problem for the maritime industry. Its impact on vessel speed and propulsion, and ultimately fuel consumption and atmospheric emissions, is well documented. A recent report by the GloFouling Partnership Project even concludes that the perceived impact of ships’ biofouling on greenhouse gas (GHG) emissions is likely to have been historically underestimated by the shipping community. For example: A layer of slime as thin as 0.5 mm and covering up to 50% of a hull surface can trigger an increase of GHG emissions in the range of 20 to 25%, depending on ship characteristics, speed, and other prevailing conditions.
For more severe biofouling conditions, such as a light layer of small calcareous growth (barnacles or tubeworms), an average length container ship can see an increase in GHG emissions of up to 55%, dependent on ship characteristics and speed.
Besides increased fuel costs and potential cost-intensive hull cleaning required by port authorities, there are also other biofouling- related economic implications for vessel operators. Extensive vessel biofouling can increase engine wear and affect intakes and internal seawater systems, requiring earlier and more frequent maintenance and asset management costs than would otherwise be needed. Some even argue that reduced vessel speed and longer voyages mean increasing crew costs relative to the distance of travel routes.
Regulations, standards and practices
According to a report published by the IMO in January 2022 (PPR 9/ INF.24), inconsistency in biofouling and in-water cleaning policies creates a major challenge for the shipping industry. While the report identifies several regional, national and sub-national biofouling policies and practices already in place, it also concludes that comprehensive biofouling management policies are not widespread and those that do implement comprehensive policies, such as New Zealand and California, are not consistent.
Of the many guidelines and industry standards relevant to biofouling management, the most wide-ranging are the IMO Biofouling Guidelines. These non-mandatory guidelines aim to provide a globally consistent approach to the management of biofouling and include best practice recommendations for minimising biofouling. A key component of the guidelines is the preparation of ship-specific biofouling management plans (BFMP) and biofouling record books (BFRB). There are also specific recommendations for what to include in a BFMP and BFRB, and a template for each. This documentation is also the cornerstone of many current and proposed national and sub- national biofouling management policies and practices, such as those of New Zealand, California, and more recently, Australia. Provision of this documentation is also expected to be a key requirement under US federal law once the new vessel discharge standards, proposed under its Vessel Incidental Discharge Act (VIDA), have been finalized and standards for implementation agreed.
The Report • September 2022 • Issue 101 | 81
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