Environmental Impact of underwater noise from leisure boats - quantifying impact and estimating efficiency of measures

Engine-powered leisure crafts emit underwater noise and often visit shallow, coastal sea areas that function as nursery habitats for many marine species. Since underwater noise affects marine life there is an imminent risk that the marine ecosystem is negatively affected.

The goal of the project is to study underwater noise of motorboats with a focus on the source and on the pressure and impact of noise on a marine ecosystem of high conservation value as well as give recommendations on how to decrease the pressure. Field trials are undertaken to characterize the source for a variety of motorboats.

A source model will be developed describing the source as a function of speed, power and type of boat.

Autonomous hydrophone loggers will be deployed to measure noise levels in areas on the East and West Coast of Sweden, which is frequently visited by motorboats.

A soundscape model of the study area is developed based on the source model, measured noise levels and monitoring of the boats in the area. The methodology is used to develop noise maps of the area, which are further used to estimate impact.

By changing boat behaviour, using the model, we evaluate the efficiency of different measures, such as speed reduction and no-go zones. The results are used to develop tools and recommendations to regulators, boat owners and industry.