Climate change is increasing water temperatures, causing whales to become disorientated and collide more frequently with vessels in North America.
Giant blue and North Atlantic right whales are the most affected, with an increase of 10% of fatal vessel collisions in 2018 alone. North Atlantic right whales are so affected that they are about to be put on a list of animals at risk of extinction, Nick Record principal investigator of the Bigelow Laboratory of Ocean Sciences in East Botthbay, Maine, noted.
Scientists and conservationists estimate the number of fatal collisions with ships are far greater than reported as whales often sink and their bodies don’t wash ashore, relying on the vessel reporting the collision.
The warming oceans have caused the whales to search for food in busy shipping lanes, “When one of their main food resources goes away, it means they start exploring new areas for food,” Record said, “And that means they’re encountering all new sources of mortality because they are going into these places where they are not protected.”
The International Maritime Organisation (IMO) published a guidance in 2009 recommending affected member states to impose speed limits for vessels operating where whales are known to migrate to or inhabit. The IMO stressed that these type of collisions are also dangerous for the vessel, including cracked hulls; damaged propellers, propeller shafts, and rudders; damaged port and starboard aft strut actuators; broken steering arms; and ruptured seawater piping.
The US government has, in 2008, imposed speed limit zones, known as seasonal management areas, for vessels of up to 10 kts. This has decreased the number of whale deaths due to ship strikes from around 2 to 0.33 per year, according to a study carried out by Julie van der Hoop, a biological oceanographer at Woods Hole Oceanographic Institution in Massachusetts.
Jessica Redfern, an ecologist from the Anderson Cabot Center for Life in the Ocean, New England, called for “a broader area where ships do not travel.”
However, taking into consideration of the demands of global trade, it may require an adjustment of speed limit zones to fit in with the new behaviour of whales rather than creating larger areas prohibiting merchant vessels. “The animals have moved into areas where there weren’t management rules in place to protect them. In a sense, the deck got reshuffled,” said Sean Hayes, head of the protected species branch for the National Oceanic and Atmospheric Administration.