Strategies

The antifouling sector, mainly fulfilling the needs of the shipping industry, has for decades undertaken a great deal of research into developing toxic and to a minor extent non-toxic antifouling strategies. Virtually none of this work has considered the specific needs and issues related to aquaculture. It is essential to use the acquired knowledge from shipping as a base to develop sustainable approaches to reducing the biofouling problem within aquaculture.

A diverse selection of potential antifouling solutions is summarised in the diagram below. Selecting a strategy from the diagram provides a description of the how current or future strategies aim to prevent or reduce biofouling. More details are available from the drop down list for some of the strategies more closely investigated by the CRAB Project or already in widespread use throughout the aquaculture industry.

Greater details can be found in the Best Practice Guidelines. Not all strategies are commercially available at present and many are still being trialled or investigated for applicability by the aquaculture sector.

Choose a strategy using the list box

Or choose a fact sheet using the strategy overview

Metals, particularly silver and copper have long been known for their anti-microbial properties. Copper has been adopted as the metal of choice for most applications. However it is possible that environmental regulations such as the BPD could end its use. Other refers to all other coating related techniques apart from fouling release and metallic coatings. Fouling does occur on these non-stick or fouling-release coatings but can be easily removed. Some products have also an inherent antifouling performance. The best systems are self cleaning when fouling load is heavy. No active ingredient/biocide is released from the material. The antifouling works by other methods. Coatings based on leaching of low/non-toxic active ingredients, such as enzymes or natural products (e.g. furanones from algae, pepper extracts or menthol extracts). Biocide is released into the local environment & deters organisms from settling and/or kills the fouling after settlement. A wide range of technologies exist for the shipping inustry, while only low-tech, low cost coatings are used in aquaculture. Antifouling property of coating is based on leaching of an active ingredient. Coating systems are based on leaching or non leaching of biocides. Quite simply this includes all the cleaning techniques used or in development for aquaculture. Using electricity and associated reactions to deter and/or kill fouling. Local and in-situ generation of biocides (Cl, hydrolysis, Cu2+ generation and deposition), pH shifts and charge. Need conductive surface. Advantage: can be switched on and off. This group of techniques includes all methods that do not involve coating the submersed material. Metal cladding Organo-metallic coating Hydrogels Surfaces with defined micro-structures Spiky coatings On demand systems Removable foils Contact Activity Fast polishing Nanotechnology based materials Fluor-silicones Silicone PDMS Living Natural compounds Enzymes Organic biocides Copper oxide Mechanical cleaning Fresh chemical solution Freshwater dipping Air drying High pressure washing Manual cleaning Robot technology Boatwash Magnetic/electrical forces Electrolysis Surface charge Dissolute/precipitate copper Physical deterrence UV-C radiation Biocide injection Removal of settling stages Vibrations Temperature Colour of substratum Low/High pH Natural Grazers Avoidance