A recent research study reveals that critically endangered North Atlantic right whales are altering their feeding behavior by coming closer to the ocean’s surface at night, which heightens their vulnerability to boat collisions. The study, recently published in the respected journal PLOS One, highlights the occurrence of nighttime surface feeding among North Atlantic right whales, offering valuable insights to mitigate fatal encounters between the whales and marine vessels.
Lead researcher Jay Kirkham, a PhD candidate at Dalhousie University in Halifax, collaborated with the U.S.-based non-profit organization Ocean Alliance to attach tracking devices to 23 right whales in the Shediac Valley, an underwater valley in the southern Gulf of St. Lawrence. This region serves as a feeding ground for a portion of the estimated 384 North Atlantic right whale population during the summer months.
Using these tracking devices, Kirkham and his team collected video footage and movement data to analyze the whales’ behavior and movements. By observing video recordings of right whale feeding patterns during daylight hours, Kirkham identified unique behaviors, such as the whales opening their mouths wide to consume zooplankton, which slows down their swimming pace, requiring increased tail movement.
The researchers employed machine learning algorithms to recognize nighttime feeding activities when visual identification was not feasible. Their analysis unveiled that these whales are feeding at depths comparable to large vessels during nocturnal hours, heightening the risk of collisions. While North Atlantic right whales typically feed near the sea floor during the day, they adjust their feeding locations at night to follow their food sources.
Kirkham emphasized that these findings underscore the urgent need to address the risks posed by ship traffic and fishing gear entanglements, which are the primary causes of mortality in the right whale population. Current protection measures overseen by Transport Canada and Fisheries and Oceans Canada include speed restrictions, vessel exclusion zones, and seasonal fishing closures in the Shediac Valley to mitigate the risk of collisions.
However, Kirkham noted that a significant portion of tagged whales ventured beyond the designated vessel exclusion zone, exposing them to potential ship encounters. Transport Canada has implemented a right whale surveillance program utilizing visual and acoustic detection tools to enhance whale protection efforts. The department stressed the importance of leveraging scientific research, monitoring data, and stakeholder feedback to refine and implement effective conservation strategies for these endangered marine mammals.
