A recent research study has revealed that North Atlantic right whales, which are critically endangered, are engaging in surface feeding at night, heightening the likelihood of collisions with boats. The study, recently published in the scientific journal PLOS One, observed this nighttime feeding behavior in the whales, offering valuable insights to mitigate fatal encounters between the whales and vessels.
The primary 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, a submerged valley in the southern Gulf of St. Lawrence. During the summer, a segment of the North Atlantic right whale population, estimated at around 384 individuals, congregates in the Shediac Valley for feeding.
Kirkham utilized the recorded video footage and movement data from the tags to analyze the whales’ behavior, particularly their feeding patterns during the day. He explained that the whales exhibit distinct feeding behaviors, such as slowing down when opening their mouths to feed on zooplankton, which necessitates increased tail movement for propulsion.
The study also employed machine learning algorithms to detect nighttime surface feeding behavior in right whales when visual identification was not feasible. The findings indicated that the whales feed at a depth commensurate with large vessels at night, escalating the risk of collisions due to vertical overlap in the water column.
While right whales typically forage near the sea floor during daylight hours, they ascend in pursuit of zooplankton during nighttime hours. Kirkham emphasized that this shift in feeding behavior places them in close proximity to vessels navigating the area, increasing the likelihood of collisions and entanglements in fishing gear, which are primary causes of mortality in the right whale population.
Current protective measures for the North Atlantic right whales are overseen by Transport Canada and Fisheries and Oceans Canada, with a focus on reducing entanglements in fishing gear and enforcing seasonal fishing restrictions. Transport Canada enforces speed limits and a vessel exclusion zone in the Shediac Valley during the summer to minimize collision risks. However, Kirkham noted that a significant portion of the tagged whales spent a substantial amount of time outside the exclusion zone, exposing them to ship traffic.
In response to the study, Fisheries and Oceans Canada stated that the research could inform tailored management strategies for protecting North Atlantic right whales. Transport Canada reiterated its commitment to whale conservation through a surveillance program utilizing visual and acoustic detection tools to enhance whale protection measures in the presence of vessels. The department emphasized the utilization of scientific research, monitoring data, and stakeholder feedback to inform and enhance protective initiatives.
Overall, the study sheds light on the critical need for conservation efforts to safeguard the North Atlantic right whale population from collisions and entanglements, underscoring the importance of ongoing research and collaborative conservation measures.