Biofouling on the hulls of recreational boats kept on swing moorings and marina berths poses a risk of transporting invasive species. A survey of 360 boats was undertaken of both mooring types at six sites near Auckland, New Zealand by visual observation from the waterline and underwater video. Both methods showed that the boats on swing moorings had more biofouling than those in berths (p < 0.001), and the video found more biofouling than visual observation (p < 0.001). A survey of boat owners found that boats on swing moorings moved at lower speeds (a function of different vessel types), making their speed insufficient to dislodge biofouling and potentially increasing their biosecurity risk. Five invasive marine species were known in the study area and the video images suggested that some of these and other invasive marine species were growing on boat hulls. About 8,700 recreational boats may be moored in the region, indicating that they have the potential to disperse invasive marine species beyond their present range. |
