In addition to the ballast water of ships, biofouling is another significant vector for introduction and spread of non-indigenous species. Biofouling is the undesirable growth of underwater structures by microorganisms, plants, algae and animals. This applies in particular to ship hulls and niches.

Biofouling can lead to the establishment of invasive species which can pose a threat to human health, the environment or economic and cultural activities.

Every ship carries a certain amount of fouling, even if it has recently been cleaned or equipped with an antifouling system. The amount of fouling is influenced by a variety of factors:

  • Ship design and construction – in particular number, location and design of so-called niche areas,
  • the ship's operation mode – in particular factors such as operating speed and the ratio of sailing time to mooring time,
  • Regions the ship is visiting or staying in,
  • Ship maintenance – in particular type, age and condition of antifouling system, installation and operation of antifouling systems, cleaning techniques and dry dock handling.

IMO Biofouling Guidelines

The IMO Biofouling Guidelines (Guidelines for the Control and Management of Ships' Biofouling to Minimize the Transfer of Invasive Aquatic Species, Resolution MEPC:207 (62)) provide practical recommendations for measures that can help to minimize risks from biofouling. They are addressed to ship operators, shipowners, shipbuilders, shipyards, classification societies, manufacturers of antifouling systems, suppliers and other interested parties. The guidelines were adopted by the Marine Environment Protection Committee (MEPC) in July 2011. Biofouling Guidelines (MEPC:207 (62)) (PDF, 127KB, Not barrier-free file.)

The guidelines cover the following aspects, among others:

  • Biofouling management plan and report book,
  • Installation and maintenance of antifouling systems,
  • Underwater inspection, cleaning and maintenance,
  • Design and construction of ships.

Based on these guidelines, a further guidance was developed and adopted specifically for owners and operators of recreational craft with a length of less than 24 meters. This guidance provides additional information and recommendations for the procedure of land transport of boats. Guidance for minimizing the transfer of invasive aquatic species as biofouling (hull fouling) for recreational craft (MEPC.1/Circ.792) Guidance for minimizing the transfer of invasive aquatic species as biofouling (hull fouling) for recreational craft (MEPC.1/Circ.792) (PDF, 256KB, Not barrier-free file.)

The 2011 Biofouling Guidelines are currently undergoing an evaluation and review process. As these guidelines are not legally binding, individual countries such as Australia and New Zealand have already implemented national requirements for biofouling management for incoming ships and boats in order to protect their coastal waters from non-native species.

The IMO is also preparing the GloFouling Partnerships project. The project focuses on the worldwide implementation of the biofouling guidelines. The BSH is a strategic partner of GloFouling.

AFS Convention

The IMO Convention on Anti-Fouling Systems (AFS-Convention, International Convention on the Control of Harmful Anti-Fouling Systems on Ships, 2001) regulates the harmful environmental effects of antifouling ship paints. Tributyltin (TBT) and other highly toxic organotin compounds in antifouling paints have been banned since the convention entered into force in 2008.

Effective antifouling systems are essential in shipping, as they not only prevent introduction and spread of non indigenous species, but also improve the hydrodynamic properties of ships, resulting in fuel savings and thus reduced transport costs and harmful emissions. Against this background, effective protection against fouling is equally in the interest of ship operators and the environment.

The development and testing of efficient but environmentally friendly antifouling strategies and systems is the subject of current research.