A recent research study has discovered that critically endangered North Atlantic right whales are engaging in nighttime surface feeding, which is putting them at a higher risk of being struck by boats. The study, recently published in the peer-reviewed journal PLOS One, has unveiled this behavior among North Atlantic right whales, offering new insights to potentially prevent fatal collisions between the whales and marine 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 tags to 23 right whales in the Shediac Valley, an underwater valley located in the southern Gulf of St. Lawrence. During the summer, a portion of the North Atlantic right whale population, estimated at around 384 whales, congregates in the Shediac Valley for feeding.
The tags collected video footage and data on the whales’ movements and swimming directions. Kirkham utilized the video recordings to observe the right whale feeding behavior during the daylight hours. He noted that when right whales feed, they open their mouths resembling a large parachute, which significantly slows them down, prompting them to kick their tails more vigorously to compensate.
Through these observations, Kirkham trained a machine learning algorithm to identify nighttime feeding behavior in right whales when direct visual identification was not possible. The data indicated that whales are feeding at a similar depth to large vessels during the night, escalating the risk of collisions.
While right whales typically feed near the seafloor during the day, they ascend in the water column at night to pursue their primary food source, zooplankton. Kirkham highlighted the vertical overlap between whales and ships in the water, emphasizing the increased collision risk.
Collisions with vessels and entanglements in fishing gear are the primary causes of death among the North Atlantic right whale population. This study may contribute valuable insights for implementing conservation strategies to safeguard the whales. Currently, Transport Canada and Fisheries and Oceans Canada supervise protective measures for the population.
Fisheries and Oceans Canada stated that their focus is on preventing whale entanglements in fishing gear and enforcing seasonal fishing closures. They believe that the study findings can aid in tailoring management strategies for the protection of North Atlantic right whales. Transport Canada enforces speed restrictions and a vessel exclusion zone in the Shediac Valley during the summer to mitigate collision risks.
However, Kirkham noted that the tagged whales spent a significant portion of their feeding time outside the designated vessel exclusion zone, exposing them to ship traffic. Transport Canada mentioned having a right whale surveillance program utilizing visual and audio detection tools to protect the whales from collisions.
The department emphasized the use of advanced scientific research, monitoring data, and stakeholder feedback to enhance protection measures for the whales.