4 North Atlantic right whale deaths investigated last year were caused by ship strikes

An incident report looking into North Atlantic right whale deaths in Canadian waters in 2019 shows vessel strikes continue to be a big threat to the endangered species.

The report, compiled by the Marine Animal Response Society and Canadian Wildlife Health Cooperative, says vessel strikes caused four out of the five whale deaths investigated last year.

A total of nine right whales were found dead in and around the Gulf of St. Lawrence in 2019.

The report released Wednesday focused on the necropsy results for five right whales, all found dead between June and July 2019. It found vessel strikes caused the death of four of them, but the necropsy investigation could not determine the cause of death of the fifth.

Dr. Laura Bourque, a wildlife pathologist with Canadian Wildlife Health Cooperative, said deaths despite shipping speed limits highlight how complicated it is to prevent vessel strikes.

"Whales move around, they move great distances within relatively short periods of time," she said. 

These deaths followed a deadlier year in 2017 when 12 right whales were found dead. Entanglements and vessel strikes were the primary causes of death for seven of the whales in 2017.

There are only about 400 North Atlantic right whales remaining in the world.

Effective restrictions?

Since 2017, the government has announced new shipping speed limits and static zones of reduced speed, as well as dynamic fishing closures if whales are spotted in certain areas.

Bourque said the results of this incident report "tells us we may not be able to place static areas of regulations —creating artificial boundaries for these whales to stay in — and expect them to stay there."

She said the results of the investigation are not surprising.

"If you draw a box in the middle of the Gulf of St. Lawrence and say OK vessels will be required to slow down here to specific speed or fishing activities can't occur here ... If whales move outside that protective box they are no longer receiving necessarily adequate protection," she said.

This means Canada may need to revisit where protective measures are implemented.

She said Canada also needs to potentially review how effective surveillance measures are, so dynamic closures and restrictions could be more effective.

"The Gulf is just a very, very large area of water," she said.

Doing more

Tonya Wimmer, executive director of the Marine Animal Response Society, says Canada needs to do more.

"Everyone is doing an awful lot to try to protect these animals, understand them, reduce risk. But the reality is something's not working and these animals are still declining at an alarming rate," she said.

"We might be doing a lot. But it looks like we're gonna have to do even more."

Wimmer said it's no question that human behaviour (fishing and shipping) is what's causing the death of the whales. And when a species is at such a small population level, there may come a point where authorities have to make a choice between the feasibility of the industries, or conserving the animals.

"What we really all would like is that everyone can coexist, but it may just have to be adjusting our expectations of how we can use oceans and what harm we can bring to these animals," she said.

She said deciding whether humans need to reduce activity further, add restrictions or do something "more extreme," is in the hands of the regulators.

Investigators could not perform necropsies on the remaining four whales found in 2019, so the cause of their deaths will remain unknown, the report said.

According to the report, four live whales were also found entangled in fishing gear between June and July. One of those whales was later found dead off the eastern seaboard of the United States.

The report says in the last five years, 25 right whales have died in Canadian waters. This death toll is more than eight times higher than the right whale mortalities which occurred during the previous 28 year period.

The report makes three recommendations.

The first is to prevent further mortalities and strengthen conservation efforts. The second is for Canada to create a comprehensive marine animal health surveillance and incident program, and the third is to further invest in marine animal response personnel and organizations, as well as support for research on the topic.