(Disponible en français : Qu’est-ce qui a mal tourné pour la baleine noire de l’Atlantique Nord?)
The North Atlantic right whale (Eubalaena glacialis) reached a turning point in 2017. Between June and September, 12 of the whales were found dead in Canadian waters in the Gulf of St. Lawrence (see Figure 1). An additional five were found dead in American waters. Most of these deaths are attributed to two human-related causes: collisions with vessels, and entanglement in fishing gear.
Figure 1 – North Atlantic Right Whale Deaths and Entanglements in the Gulf of St. Lawrence in 2017, with the Seasonal Speed Reduction Zone and Snow Crab Fishing Zones Indicated.
Map prepared by Library of Parliament, Ottawa, 2018, using data from Natural Resources Canada (NRCan). Boundary Polygons. In: Atlas of Canada National Scale Data 1:5,000,000 Series. Ottawa: NRCan, 2013; Canadian Coast Guard. Speed reduction in the Gulf of St. Lawrence due to increased presence of right whales, Broadcast Notice Q1189/2017, 11 August 2017; Fisheries and Oceans Canada. Snow Crab Fishing Areas; and Daoust, P.-Y., E.L. Couture, T. Wimmer, and L. Bourque. Incident Report: North Atlantic Right Whale Mortality Event in the Gulf of St. Lawrence, 2017. Canadian Wildlife Health Cooperative, Marine Animal Response Society, and Fisheries and Oceans Canada, 29 December 2017. The following software was used: Esri, ArcGIS, version 10.3.1. Contains information licensed under Open Government Licence – Canada.
The results from six of the seven necropsies performed on dead North Atlantic right whales (hereafter right whales) in Canada are detailed in Incident Report: North Atlantic Right Whale Mortality Event in the Gulf of St. Lawrence, 2017. The authors of the report concluded:
“Necropsy findings of trauma and entanglement coincide with high level[s] of fisheries and maritime traffic in the Gulf of St. Lawrence.”
With just 451 right whales estimated to remain, population loss such as that observed in 2017 is unsustainable. Unless management actions are taken promptly to prevent these human-related deaths, the right whale could be extinct in 20 years.
Pushed to the brink of extinction by centuries of whaling, the North Atlantic right whale is listed as endangered under both the Canadian Species at Risk Act and the American Endangered Species Act. Individuals generally spend the spring, summer, and fall in Canadian feeding habitats and migrate to southern United States calving habitats for the winter.
Fisheries and Oceans Canada is the federal department charged with the recovery of this species in Canada. The Species at Risk Act recovery strategy for the right whale recognizes these top two recovery objectives:
- reducing death and injury from vessel strikes; and
- reducing death and injury from fishing gear interactions. (See Figure 2.)
Just prior to the 2017 right whale deaths, Fisheries and Oceans Canada conducted a science-based review of the effectiveness of endangered whale recovery efforts and published a summary report and engagement feedback. Following the 2017 deaths, the Minister of Fisheries, Oceans and the Canadian Coast Guard hosted a roundtable discussion with fishers, the marine transportation industry, scientists, Indigenous peoples, Atlantic provincial officials, and US officials, to identify ways to reduce human impacts on right whales.
Figure 2 – Disentanglement of a North Atlantic Right Whale from Fishing Gear
A young North Atlantic right whale entangled in fishing gear is approached by U.S. National Oceanic and Atmospheric Administration Fisheries Service scientists off the coast of Florida. Credit: NOAA News Archive 011811, NOAA Photo Library. Licenced under CC by 2.0.
A. Vessel Strikes
Right whales, naturally slow swimmers, appear to be more prone to collisions with vessels than other large whales. The broken bones, internal bleeding and severe propeller cuts that result from vessel strikes may lead to death. Whales have a better chance of avoiding a vessel or surviving a collision when vessels are travelling at slower speeds. In recent years, Canadian and U.S. governments have implemented such strategies as slowing down vessels and rerouting shipping traffic in an effort to reduce right whale deaths.
In response to the mortalities, on 11 August 2017, Transport Canada issued a “Notice to Shipping” for the western Gulf of St. Lawrence (see the dotted box in Figure 1). Vessels 20 or more metres long were required to reduce their speed to a maximum of 10 knots (18.5 km/h). Vessels that did not comply were fined.
Some members of the shipping and cruise industry noted the economic burden of speed reduction, citing increased fuel costs incurred from speeding up elsewhere along their routes to maintain their schedules. The speed restriction was lifted in January 2018 for marine manoeuvrability and safety in winter pack ice conditions, after the whales appeared to have left the Gulf of St. Lawrence.
The western Gulf of St. Lawrence speed restriction will be in place from 28 April to 15 November 2018, with possible adjustments as needed.
B. Entanglement in Fishing Gear
83% of living right whales bear the scars of having been entangled in fishing gear. Two types of fishing gear entanglement are observed: acute and chronic. Acute entanglements can cut flesh and bone, and may lead to infections, amputations, an inability to feed, or drowning. Chronic entanglements have a slower impact, as whales are forced to drag entangled gear behind them, increasing the energy required to swim and to filter feed. Chronically entangled whales may lose weight to the point that they are not healthy enough to reproduce, and they may eventually starve to death.
The Canadian Atlantic waters frequented by right whales are dense with fishing activity, where increasingly strong rope lines connect gear on the ocean bottom to marker buoys on the surface. As can be seen in Figure 1, in Canadian waters, most of the dead right whales were found within Area 12 of the snow crab fishing zone.
In response to the 2017 right whale mortalities, the Minister of Fisheries and Oceans and the Canadian Coast Guard closed Area 12 of the snow crab fishery early. The Minister later announced new rules for the 2018 snow crab fishery that aim to reduce the amount of rope and lost gear in the water.
In March 2018, the Minister announced further protective measures, including closing the southern Gulf of St. Lawrence snow crab fishery early (on 28 April 2018), requiring the removal of all snow crab fishing gear two weeks earlier than usual (by 30 June 2018), and possibly temporarily closing fixed-gear fisheries when a right whale is observed in the area.
The Government of Canada will increase right whale detection survey efforts, lift the current pause on disentanglements (in place since a tragic 2017 incident), and increase its financial support for marine mammal response groups.
C. Ecological Factors Complicating Species Recovery
Like other long-lived, large-bodied mammals, right whales are slow to reproduce and have relatively few young. Since 2010, calving rates appear to have dropped dramatically, further slowing the species’ recovery. Scientists have expressed concern about the current male-to-female ratio in the population, following the decrease in the number of females from 200 in 2010 to 186 in 2015. No new calves were seen throughout the November 2017 to February 2018 calving season.
In 2017, right whales did not frequent their traditional feeding habitats in the Grand Manan Basin and Roseway Basin, but instead fed in the more northerly Gulf of St. Lawrence. It appears that the whales followed their tiny crustacean prey as its distribution shifted northward.
Habitat necessary for the survival and recovery of a species at risk may be defined as “critical” under the Species at Risk Act. The Grand Manan and Roseway basins are recognized and protected as adult right whale foraging and feeding areas through a 2017 Species at Risk Act Critical Habitat Order, but the Gulf of St. Lawrence is not.
The continued collaboration of regulators, scientists, fishers, the shipping industry, and conservation groups would help to ensure that management actions are both effective and feasible, or are adapted as necessary.
Author: Sarah Yakobowski, Library of Parliament
Categories: Agriculture, Environment and Natural Resources