A recent research study discovered that critically endangered North Atlantic right whales are engaging in nighttime surface feeding, which is putting them at a higher risk of collisions with boats. The study, recently published in the peer-reviewed journal PLOS One, highlighted this behavior in North Atlantic right whales, offering valuable insights to prevent fatal encounters between the whales and vessels.
Lead author of the study, Jay Kirkham, a PhD student at Dalhousie University in Halifax, collaborated with the U.S.-based non-profit Ocean Alliance to attach tags to 23 right whales in the Shediac Valley, located in the southern Gulf of St. Lawrence. Each summer, a segment of the North Atlantic right whale population, estimated at around 384 whales, congregates in the Shediac Valley to feed.
The tags collected video footage and data on the whales’ movements and swimming patterns. Utilizing the video recordings, Kirkham observed the whales’ feeding behavior during daytime hours. He noted that when the whales feed, their mouth openings act like a large parachute, slowing them down and necessitating increased effort from the whales by kicking their tails faster.
Kirkham utilized these observations to train a machine learning algorithm capable of identifying nighttime feeding behavior in right whales when direct visual identification was not possible. The data revealed that the whales feed at a depth similar to large vessels at night, elevating the risk of collisions. While right whales typically feed near the sea floor during the day, they follow their food source, zooplankton, higher in the water column at night.
According to Kirkham, collisions with vessels and entanglements in fishing gear are the primary causes of mortality in the right whale population. The findings of this study could aid in the development of conservation strategies for the whales. Current protection measures for the population are overseen by Transport Canada and Fisheries and Oceans Canada.
Fisheries and Oceans Canada stated that its measures concentrate on preventing whale entanglements in fishing gear and enforcing seasonal fishing closures. The department acknowledged that the study could assist in tailoring management measures for the protection of North Atlantic right whales. Transport Canada enforces speed restrictions and a vessel exclusion zone in the Shediac Valley during the summer to mitigate the risk of collisions with right whales by boats in the area.
Despite these measures, Kirkham noted that the tagged whales spent approximately a quarter of their feeding time outside the vessel exclusion zone, exposing them to ship traffic. Transport Canada disclosed that it operates a right whale surveillance program utilizing visual and audio detection tools to safeguard the whales from collisions.
The department emphasized the use of cutting-edge scientific research, monitoring data, and stakeholder feedback to inform its protective measures for the right whale population.