Dipping in Freshwater

Generally used for killing fouling on shellfish stock but can also be used on infra-structure. This technique can kill fouling species not resistant to low salinities.

Applicable to:

Shellfish
- Stock and infrastructure.

Methodology

Mussels are not unduly affected by a 2 day soak in freshwater, which kills off fouling species.

Key Factors Positive

- Stock and equipment can be soaked in freshwater at relatively low cost.
- User friendly.
- The effectiveness in removing fouling is good.
- Can also be used as a control method for reducing the numbers of juvenile sea stars on mussel lines. Although not strictly a fouling organism, predation by sea stars can substantially increase stock mortality.

Key Factors Negative

- Water must be changed to maintain salinity at 1 psu.
- Mussels are fast growing so it may be best for mussel farmers to use freshwater only as an end of season treatment.

Cost Benefit

- None of the CRAB partners use this strategy at present so no cost benefit analysis was possible.

Conclusions/ Discussion

- Further benefits are apparent when seed stock is transported between
sites, as the stock can be soaked to kill fouling organisms on route.
- This strategy also reduces the risks of unwanted species being transported across regions.