A recent research study has revealed that North Atlantic right whales, classified as critically endangered, are engaging in surface feeding behavior at night, heightening their vulnerability to boat strikes. The findings, recently published in the reputable journal PLOS One, shed light on this nighttime feeding habit observed in these whales, offering valuable insights for preventing fatal collisions with vessels.
The lead author of the study, Jay Kirkham, a PhD candidate 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, located in the southern Gulf of St. Lawrence. This area serves as a gathering spot for a segment of the North Atlantic right whale population, estimated at around 384 individuals, during the summer months.
Kirkham explained that the tracking devices captured video recordings and movement data of the whales, aiding in the observation of their feeding patterns both during the day and at night. The video footage revealed the distinctive feeding behavior of right whales, where they slow down significantly by opening their mouths wide to consume zooplankton, requiring increased effort in propelling themselves forward by vigorously moving their tails.
Utilizing the recorded observations, Kirkham developed a machine learning algorithm capable of identifying nighttime feeding activities in right whales when visual identification was not feasible. The data highlighted that whales feed at a similar depth to large vessels during the night, elevating the risk of collisions between the two entities.
While right whales typically feed near the sea floor during daylight hours, the study found that they ascend in the water column at night, tracking their zooplankton prey. Kirkham emphasized the vertical overlap between the whales and ships in the region, underlining the heightened collision risk.
Collisions with vessels and entanglement in fishing gear are leading causes of mortality among North Atlantic right whales. The study aims to contribute vital information to guide conservation efforts for these whales, with Transport Canada and Fisheries and Oceans Canada currently overseeing protective measures for the population.
Fisheries and Oceans Canada stated that their initiatives focus on preventing whale entanglements in fishing gear and enforcing seasonal fishing restrictions, with the study expected to aid in tailoring management strategies for safeguarding North Atlantic right whales. Transport Canada implements speed limitations and maintains a vessel exclusion zone in the Shediac Valley during the summer to mitigate collision risks. Despite these measures, Kirkham noted that a significant portion of tagged whales spent a considerable amount of time outside the exclusion zone, exposing them to ship traffic.
Transport Canada highlighted its whale surveillance program, utilizing visual and audio detection tools to enhance whale protection from collisions. The department emphasized the use of advanced technologies and scientific insights to inform protective measures and solicited feedback from stakeholders in this process.