Overland transport of recreational boats is among the most important distribution vectors for aquatic invasive zebra and quagga mussels between inland waters. Simple measures such as instructing boat owners how to prepare their boat for transport so that the boat does not carry invasive species are considered to be important prevention measures. Nevertheless, the net effects of such measures are poorly understood and the boat cleaning behavior of boat owners has never been studied in detail before the implementation of such preventive measures. Using a “self-report” questionnaire, we investigated the boat cleaning behavior of boat owners in Switzerland where almost no preventive measures have been taken yet. We found that the self-reported boat cleaning rates are high, with 92% of boaters cleaning their boat upon finding mussels attached to their boat and 84% of them cleaning their boat before a transport. Nevertheless, only half of the boat owners report using high pressure washing to clean their boat before overland transport and many use ineffective cleaning methods.
We show the importance of informing boat owners on the appropriate methods to remove invasive species from their boat and suggest that high pressure washing facilities should be made available at all potentially infested water bodies. Furthermore, our analysis shows that the boat cleaning behavior could be significantly improved by changing how boat owners value the perceived costs and benefits of cleaning, as well as by increasing their awareness of the potential negative impacts on aquatic ecosystems caused by non-native species. With regard to a possible spread of zebra mussels to uninfested alpine lakes and the imminent spread of quagga mussels in Switzerland, we conclude that the Swiss boating community would be open to accepting implementation of prevention measures.