A recent research study has discovered that critically endangered North Atlantic right whales are engaging in surface feeding at night, raising the likelihood of collisions with boats. The study, recently published in the peer-reviewed journal PLOS One, observed nighttime surface feeding behavior in North Atlantic right whales, offering new insights that could aid in preventing fatal collisions between the whales and vessels.
The 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 tracking devices to 23 right whales in the Shediac Valley, an underwater valley in the southern Gulf of St. Lawrence. During the summer, a segment of the North Atlantic right whale population, estimated to be around 384 whales, congregates in the Shediac Valley for feeding.
Kirkham explained that the tracking devices captured video footage and data on the whales’ movements and swimming directions. He utilized this video footage to observe right whale feeding behavior during the daytime. According to Kirkham, the video footage revealed that when right whales feed, their mouth acts like a large parachute that slows them down, prompting them to increase tail movement to compensate.
Incorporating these observations, Kirkham developed a machine learning algorithm to identify nighttime feeding behavior in right whales when visual identification was challenging. The data indicated that whales are feeding at a similar depth as large vessels during the night, heightening the risk of collisions. While right whales typically feed near the seafloor during the day, they follow their food source, zooplankton, to higher water levels at night.
Collisions with vessels and entanglements in fishing gear are major causes of mortality in the North Atlantic right whale population. The study findings could potentially guide conservation efforts for the whales. Management measures for the population are currently overseen by Transport Canada and Fisheries and Oceans Canada. Fisheries and Oceans Canada stated that its strategies concentrate on preventing whale entanglements in fishing gear and enforcing seasonal fishing closures, with the study offering valuable insights for tailored conservation measures.
Transport Canada enforces speed limitations and a vessel exclusion zone in the Shediac Valley during the summer to mitigate the risk of boat-whale collisions. However, Kirkham highlighted that the tagged whales spent a significant portion of their feeding time outside the exclusion zone, exposing them to ship traffic. Transport Canada emphasized its right whale surveillance program, using visual and audio detection tools to safeguard whales from collisions and incorporating scientific research and stakeholder feedback to enhance protection measures.