A recent research study discovered that critically endangered North Atlantic right whales are engaging in surface feeding at night, heightening their vulnerability to collisions with boats. The study, recently published in the peer-reviewed journal PLOS One, highlighted the nocturnal surface feeding behavior of North Atlantic right whales, presenting new insights that could aid in preventing fatal encounters between the whales and vessels.
Lead author of the study, Jay Kirkham, a PhD candidate at Dalhousie University in Halifax, collaborated with the U.S.-based non-profit organization Ocean Alliance to attach tags 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 at around 384 whales, congregates in the Shediac Valley for feeding.
Utilizing video footage and movement data from the tags, Kirkham observed the feeding behavior of right whales during the daytime. He described the whales’ feeding mechanism as involving a significant slowdown when they open their mouths, necessitating increased effort to maintain speed by vigorously moving their tails.
To address the challenge of identifying nighttime feeding behaviors visually, Kirkham developed a machine learning algorithm trained on the recorded observations. The data revealed that right whales are feeding at a similar depth as large vessels during the night, escalating the risk of collisions. While these whales typically forage near the seabed during daylight hours, they follow their zooplankton prey higher up the water column at night.
Kirkham emphasized that collisions with vessels and entanglements in fishing gear are primary causes of mortality in the right whale population. Insights from this study could inform conservation strategies for protecting these endangered marine mammals.
Current protection measures for the North Atlantic right whales are overseen by Transport Canada and Fisheries and Oceans Canada. Fisheries and Oceans Canada focuses on preventing entanglements in fishing gear and enforcing seasonal fishing closures, while Transport Canada implements speed limits and a vessel exclusion zone in the Shediac Valley during the summer to mitigate collision risks.
Despite these measures, Kirkham noted that the tagged whales spent a significant portion of their feeding time outside the designated vessel exclusion zone, exposing them to ship traffic. Transport Canada employs a surveillance program using visual and audio detection tools to safeguard right whales from collisions.
The government departments affirmed that ongoing research, monitoring data, and stakeholder feedback are integral to shaping effective protection measures for the North Atlantic right whales.