Whales Keep Dying off the East Coast and Scientists Don’t Know Why

Another right whale was found dead off the Gulf of St. Lawrence yesterday, raising the death toll to 10 since June 7, a significant number given that researchers believe there are only about 525 of these creatures left in the world.

But scientists are still stumped as to why these whales are dying at such a high rate and in such a specific location.

They've been appearing out of nowhere too. Usually, right whales migrate in the winter to areas off the coast of Florida and George. In the summer time, they'll also travel to Cape Cod Bay in the US, or to the Bay of Fundy in Canada. But for whatever reason they've been showing up on the Gulf of St. Lawrence and have yet to show signs of leaving. This has caused havoc to local fisheries. Thousands of commercial ships have had to deal with route diversions or movement of shipping lanes.They've also led to an increase of whale entanglements, even causing the death of one man who tried to free a whale from a net.

As the mystery continues to unfold, there are a few theories floating around, though none of them have proved conclusive.

At least three of the whales found so far were believed to have died from blunt force trauma consistent with being struck by a large vessel. In one case, a whale was found dead after becoming entangled in fishing gear, according to Tonya Wimmer, director of the Marine Animal Response Society, and a researcher who's been following the string of deaths. Though, it's still up in the air whether the whale got caught before or after it was found dead.

It's fairly common for whales to die by boat or entanglement. According to a report by Fisheries and Oceans Canada, between 1970 and 2007, nearly half of all the documented whale deaths were caused by fishing net entanglements or collisions with vessels. Though, that number could be higher. Up to two-thirds of human-caused deaths are never discovered; in most cases, right whales will likely sink because of poor health just before death.

The increased deaths seem to correlate with the increase of right whale sightings in the area. In an interview with CBC, Fisheries and Oceans scientists Matthew Hardy said that these sightings were the highest in recent memory. Over the last four to five years right whales have been showing up in the region, but it's only now that science, government, and industry are catching wind of it. Though, some researchers believe the increased sightings could just be the result of increased surveillance efforts.

With more whales in the region, and with increased human activity, Canada's Department of Fisheries and Oceans closed some new crab fisheries early in response to the deaths, and are asking ships in the high-traffic Gulf of St. Lawrence to voluntarily keep their speed to 10 knots or less.

Some researchers are also speculating that warming ocean temperatures due to climate change may be killing some of these whales off.

Warming waters could be triggering toxic algal blooms that could be harming whales and other marine mammals. According to one study in 2014, more than 40 percent of marine mammal strandings in the US have been attributed to HAB toxins in the last two decades.

In 2015, the corpses of 14 large whales were found off the coast of British Columbia (nearly 60 including nearby Alaska). Scientists believed that the deaths could be linked to the "warm blob"—an area of warmer than normal ocean water that may have triggered toxic algal blooms. Of the 14 whales found dead in BC, scientists performed necropsies (whale autopsies) on eight. Those eight were found to have had high levels of domoic acid, a neurotoxin created by harmful algal blooms.

Though, there's currently no evidence correlating what happened in BC and the current 10 right whale deaths, researchers are still analyzing the corpses of those whales with results coming soon.

Kimberly Davies, post-doctoral fellow in the oceanography department at Dalhousie University, rounded a team of researchers in 2015 and published a research paper indicating that these whales may be dying off because of shortage of food supply, causing them to migrate from the Bay of Fundy off the coast of Nova Scotia and the coast of Maine, to the Gulf of St. Lawrence.

With only 525 right whales believed to alive right now, 10 deaths amounts to about a 1 to 2 percent decrease in the total population. This makes them currently one of the most endangered large whales in the world. If they continue to die at this rate, the species may go extinct.

As of yet, right whales have been listed as an endangered species under the Species at Risk Act, meaning there are a many legal provisions regarding the treatment of these animals, including provisions against killing, harming, harassing, capturing, taking, possessing, collecting, buying, or selling these whales. There's also a Recovery Strategy and a Proposed Action Plan being developed by the Canadian government.

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