What mitigation methods are available to reduce the risks?
Preventing new introductions is the most cost effective means of limiting invasive species impacts. The first step in assessing risk reduction is to determine the effect of the ship’s journey on organism quantity and quality. The risks may be low if the fouling community sloughs off during transit or fails to survive the journey. Mitigation options include towing vessels between freshwater and saltwater for extended periods. The Columbia River was used for this purpose when the USS MISSOURI was moved to Hawaii from Puget Sound (although this was not 100% successful). Other options include in-water cleaning of the hulls (this is unlikely to be carried out because of expense and risks with contamination from paint/rust on the hulls) and dismantling ships in a dry-dock facility.
