A recent research study has discovered that critically endangered North Atlantic right whales are engaging in shallower nighttime feeding, which heightens the danger of collisions with boats. The study, released in the peer-reviewed journal PLOS One, highlights the phenomenon of nighttime surface feeding among North Atlantic right whales, offering valuable insights for preventing fatal encounters between the whales and ships.
Lead author of the study, Jay Kirkham, a PhD student at Dalhousie University in Halifax, collaborated with the U.S.-based non-profit Ocean Alliance to tag 23 right whales in the Shediac Valley, an underwater valley in the southern Gulf of St. Lawrence. This valley serves as a feeding ground for a segment of the North Atlantic right whale population, estimated at around 384 whales, during the summer months.
Kirkham explained that the tagging devices captured video footage and data on the whales’ movements and swimming patterns. By analyzing the video footage, Kirkham observed the feeding behavior of right whales during daylight hours.
According to Kirkham, a machine learning algorithm was trained using these observations to detect right whale feeding activities at night when visual identification was not feasible. The data revealed that the whales feed at a depth comparable to that of large vessels at night, increasing the risk of collisions.
While right whales typically feed near the sea floor during the day, they ascend in the water column at night in pursuit of their primary food source, zooplankton. Kirkham emphasized that this behavioral shift places them in close proximity to ships navigating the area.
Collisions with vessels and entanglements in fishing gear are identified as the primary causes of mortality among the North Atlantic right whale population. The findings of this study may contribute to the development of conservation strategies for protecting these whales.
Current protection measures for the right whale population are overseen by Transport Canada and Fisheries and Oceans Canada. Transport Canada enforces speed limits and a vessel exclusion zone in the Shediac Valley during the summer to mitigate the risk of collisions. However, Kirkham noted that the tagged whales spent a significant portion of their feeding time outside this exclusion zone, leaving them vulnerable to ship traffic.
In response to the study, Fisheries and Oceans Canada highlighted its focus on preventing whale entanglements in fishing gear and enforcing seasonal fishing closures. The department expressed that the study findings could aid in the formulation of tailored conservation measures for North Atlantic right whales.
Transport Canada, on the other hand, emphasized its whale surveillance program, which utilizes visual and audio detection tools to safeguard the whales from collisions. The department underscored the importance of leveraging scientific research, monitoring data, and stakeholder feedback to inform protective measures for the whales.