A recent investigation has discovered that the critically endangered North Atlantic right whales are engaging in nighttime surface feeding, which puts them at a higher risk of being struck by boats. The study, recently released in the peer-reviewed journal PLOS One, highlights the nocturnal feeding behavior of North Atlantic right whales and suggests potential strategies to reduce fatal collisions between these whales and vessels.
The primary researcher, Jay Kirkham, a doctoral 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 located 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 purposes.
Kirkham utilized the tracking data, including video recordings of the whales’ movements and feeding patterns, to analyze their behavior. By observing the whales during the day, he noted their feeding mechanisms, such as their method of slowing down by opening their mouths, which requires them to increase tail movements to compensate for the reduced speed.
The research team employed these observations to develop a machine learning algorithm that could recognize nighttime feeding behavior, which indicated that the whales feed at depths similar to those of large vessels at night, amplifying the risk of collisions. While the whales typically feed near the seabed during the day, they ascend in the water column at night to pursue their primary food source, zooplankton.
Kirkham emphasized the importance of addressing the potential threats posed by ship traffic, as collisions and entanglements in fishing gear are the leading causes of mortality in the North Atlantic right whale population. Current protection measures overseen by Transport Canada and Fisheries and Oceans Canada focus on mitigating entanglements and enforcing seasonal fishing closures, with speed restrictions and vessel exclusion zones implemented in the Shediac Valley during the summer to minimize collision risks.
Despite these efforts, Kirkham highlighted that a significant portion of the tagged whales spent a considerable amount of time outside the designated vessel exclusion zone, leaving them vulnerable to maritime traffic. Both Transport Canada and Fisheries and Oceans Canada utilize advanced technologies, including acoustic monitoring systems and visual detection tools, to safeguard the whales and inform protective measures based on the latest scientific findings and stakeholder feedback.