Measures taken to protect North Atlantic right whales in the Gulf of St. Lawrence from being struck by ships and getting caught in fishing gear may not be enough, a scientific review by Ottawa shows.

Speed restrictions and fishing-zone closures in the Gulf of St. Lawrence have lowered risks that the endangered whales will be harmed, but dangers remain — especially in the waters outside protected zones, according to the national study.

The review was done late last year by scientists who work in federal departments and universities across Canada, looking at data compiled by marine-mammal experts over the last three years. They wanted to get a better idea of how many whales congregate in Atlantic Canadian waters and why. They also tried to determine the risks that right whales face from vessel strikes and entanglements in the Gulf of St. Lawrence, the semi-enclosed body of water that lies between the four Atlantic provinces and the eastern shores of Quebec.

Six North Atlantic right whales have died in eastern Canadian waters since early June this year and one was spotted alive but entangled in fishing gear last week. No deaths were recorded last year in Canadian waters, but 12 right whales were found dead in 2017, mainly from ship strikes and entanglements.

Every single death is a major blow to the endangered species. Just over 400 right whales remain in the world, it's estimated.

The federal scientific review confirmed an increased presence of right whales in the Gulf of St. Lawrence since 2015, with the highest concentrations in warmer months. They come seeking food, and their favourite meal — a particular small crustacean — has become abundant in the Gulf of St. Lawrence since 2010.

Aerial surveys estimate there were at least 190 right whales in the Gulf last year, half the total known population everywhere.

When it comes to the likelihood of these whales being struck by marine vessels, the scientists found mandatory speed restrictions implemented in 2017 in response to multiple whales washing up dead on eastern Canadian shores reduced the risk of lethal strikes by 56 per cent. Mandatory speed restrictions of 10 knots for vessels 20 metres or longer were enacted again last year and have been in place this year since April 28.

More ships in the gulf

Just outside these speed-restricted zones, however, the danger of deadly strikes became significantly greater, the review says.

This is due in part to increased vessel traffic. But there was also a concern about boats speeding up just before they reached the boundaries of the speed-restriction zone, notably in the heavily travelled waters between New Brunswick and P.E.I., "likely in anticipation of reducing their speed within that zone," the report says.

"This resulted in a near 100 per cent chance of the NARW (North Atlantic right whale) lethality should a strike occur."

The scientists also raised concern about the size of the slowdown zone being reduced in 2018 in an area north of Anticosti Island, an especially risky area for vessel strikes. This, coupled with limited monitoring of the whales in some of these areas, prompted calls for increased surveillance.

Fishing gear still an issue

The scientists noted right whales have been heavily concentrated in busy fishing areas of the Gulf of St. Lawrence in the last three years.

Fishing restrictions imposed in some of the areas where the whales have been most prevalent have helped, but whales continue to become entangled, mainly in snow crab gear. There were at least two entanglements in 2016, seven in 2017 and at least three in 2018.

More information on the behaviour of the whales could lead to better protection. (NOAA/The Associated Press)

The scientists indicated they found it difficult to fully measure the risks of future entanglements due to a lack of data on fisheries efforts, including inconsistencies in reporting of where fishing gear is positioned and a lack of information about when gear is placed in the water.

Overall, the scientists noted a lot of uncertainty when it comes to trying to predict how big an issue this will continue to be, as the right whales' presence in the Gulf of St. Lawrence is relatively new.

Surveillance and detection efforts have increased since 2017 — including through listening for whale calls, aerial surveys and boat-based visual observations. But all of these methods have problems with accuracy due to often challenging weather conditions and ambient noise.

Data lacking

More monitoring is needed to provide solid, scientific advice for decisions on policies to address this issue going forward, the review says.

"Gaining improved knowledge of diving and surfacing behaviours of [right whales] is necessary to improve our ability to ... estimate risk from fishing gear and vessels."

The two federal departments involved in this issue, Transport Canada and Fisheries and Oceans Canada, have been closely monitoring the presence of right whales in the Gulf and provide regular updates that can lead to changes to the areas where boats have to slow down and where fishing has to stop.

But even with speed restrictions in place, some boats continue to speed. A compliance report posted on the Transport Canada site shows 111 vessels were caught travelling over the 10-knot speed limit between April 28 and June 27 of this year. More than 90 per cent of those cases were closed with no penalties and nine cases remain under review.

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