Strategies

Colour of Substratum

Colour affects settlement of certain fouling species. This can be either settlement inhibition or induction. This can be used in conjunction with other antifouling strategies. Studies have proved the benefits of using some colours to control some fouling species.

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Methodology

Colours that reduce fouling may be dark blue, green, yellow or white. Colours that increase fouling may be black and red. However, further research is needed to prove these claims and also to investigate the effect in different circumstances, for example at varying depths and sea conditions.

Key Factors Positive

- In testing in CRAB the colour of the substratum did play a factor in settlement (but further research is necessary to determine the relationship between colour and settlement).

Key Factors Negative

- The colour approach is most likely not sufficiently effective by itself but useful in combination with other strategies (e.g. give a fouling-release coating a minimum fouling colour).
- Currently the most common colours used in aquaculture are the most heavily fouled. It will therefore be more expensive (initially) to produce these items in different colours.

Cost Benefit

The black trays are cheapest but if white or light blue trays resulted in reduced levels of fouling with lower cleaning costs, then the extra cost may be warranted.

Conclusions/ Discussion

Colour is by no means a solution on its own, however combined with other techniques it could be very useful. It is something that farmers can experiment very easily with themselves without significant extra cost.

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