How do Boats Avoid Whales?
Collisions between ships and cetaceans are rather frequent and are a recognized cause of cetacean mortality in the world, despite the fact that the former are rather loud and the latter have an excellent sense of hearing. A number of working groups are seeking practical solutions to help ships avoid collisions with whales. Such solutions include tools to inform mariners of the presence of marine mammals, technological solutions or, considered even more effective, changes in navigation procedures such as limiting shipping traffic or reducing vessel speeds.
As an example of a solution, in the St. Lawrence Estuary, measures to mitigate the risk of ship strikes with marine mammals were identified by the Working Group on Marine Traffic and Protection of Marine Mammals, also known as the G2T3M. Thanks to the results of their work, shipping operators adopted voluntary steps to reduce speeds and avoid certain areas with high whale densities.
Additionally, vessels operating in the Canadian waters of the Bay of Fundy, a critical habitat for the North Atlantic right whale, are advised to avoid (whenever possible) two particularly important areas for right whales, or to post lookouts at the bow of the boat if they absolutely must pass through these areas, as whales are not always able to avoid them. In the United States, aircraft fly over the Georgia and Florida coasts (calving grounds) to inform boat operators of whale movements and encourage them to exercise caution. In Cape Cod Bay, the US National Oceanic and Atmospheric Administration has established a warning system for whales in the navigation corridor to Boston. Buoys are equipped with hydrophones capable of picking up the calls of whales. If a whale is detected, a signal is sent to ships so they can slow down in this sector.
In the coastal waters of California, where traffic is quite heavy, shipping lanes overlap with areas frequented by eastern North Pacific blue whales. American researchers have also proposed changes to shipping lane routes.
Still farther afield, in the Pelagos Sanctuary for Mediterranean Marine Mammals, a dedicated observer spends his or her days detecting animals from an optimized platform aboard the craft to help avoid collisions. Meanwhile, technology takes the night shift, with a device called the Night Navigator, which uses thermal infrared technology and a system to automatically detect the spouts of large cetaceans.