High passenger traffic in mid-summer puts whales at risk particularly in the Liguro-Provençal Basin.© Souffleurs d'Écume
Mapping the risk of ship strike with endangered whales
Among the numerous threats for large cetaceans, ship strike and noise pollution are likely to be the highest. While the Mediterranean Sea is a major forage ground for the endangered fin whale (Balaenoptera physalus) it also represents 30% of all international maritime traffic concentrated within only 0.8% of the global ocean surface.
In order to investigate the impact of maritime corridors in the open sea, the JRC has merged data on daily traffic data and with information on which habitats are favourable to fin whales favourable habitats to produce maps of potential risk of strike. The potential habitat model, which is also developed at the JRC, uses daily satellite environmental data and thus captures the high variability at large scale.
The results show that the Liguro-Provençal Basin, and particularly the area of the Marine Mammal Pelagos Sanctuary, has a high potential collision risk in mid-summer due to high passenger traffic.
The proposed method of combining potential habitat and maritime traffic data provides an added value for policy-makers. Besides mapping the potential risk of ship strike, the JRC’s work highlights the feasibility of future operational mitigation systems. For instance, the daily product of potential habitats could be used in a near real-time system on board of large vessels to increase awareness of the risk of collisions. They can also be used as complementary data to the developing real-time plotting systems of cetaceans. Researchers also propose to install moored acoustic buoys along vessel corridors that transmit information about the whales' position to the vessels in real-time, allowing them to adapt their speed when passing prime habitats. Mitigation measures would also consist in reducing vessel speed when prime habitat conditions occur. Further research is needed to investigate whether traffic noise induces an effective loss of habitat for fin whales.