A recent research study has discovered that critically endangered North Atlantic right whales are now feeding closer to the surface of the ocean at night, which heightens their chances of being struck by boats. The study, recently released in the peer-reviewed journal PLOS One, has documented the nocturnal surface feeding behavior of North Atlantic right whales. This new evidence can potentially aid in averting fatal collisions between the whales and maritime vessels.
Jay Kirkham, the lead author of the paper and a PhD student at Dalhousie University in Halifax, collaborated with the U.S.-based non-profit organization Ocean Alliance to attach tags to 23 right whales in the Shediac Valley, located in the southern Gulf of St. Lawrence. During the summer, a portion of the North Atlantic right whale population, estimated to be 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 this video footage to observe the right whale feeding behavior during daylight hours. He described how the whales slow down significantly when they open their mouths to feed, necessitating them to exert more effort by moving their tails at a higher and faster rate.
The study also involved training a machine learning algorithm to recognize right whale feeding patterns at night when visual identification was not possible. The data revealed that the whales feed at a depth comparable to that of large vessels during nighttime, 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 to follow their food source, zooplankton.
Kirkham commented on the potential dangers posed by large ships that extend several meters below the water surface, overlapping with the depth at which the whales feed at night. Collisions with vessels and entanglements in fishing gear are the primary causes of mortality among the population, underlining the importance of this study in guiding conservation efforts for the whales.
Transport Canada and Fisheries and Oceans Canada are currently responsible for overseeing protective measures for the North Atlantic right whale population. Fisheries and Oceans Canada highlighted that the study could assist in tailoring management strategies to safeguard the whales, focusing on preventing entanglements in fishing gear and enforcing seasonal fishing closures.
Transport Canada has implemented speed restrictions and a vessel exclusion zone in the Shediac Valley during the summer to minimize the risk of collisions between boats and right whales in the area. Despite these measures, Kirkham noted that the tagged whales spent a significant portion of their feeding time outside the exclusion zone, exposing them to ship traffic.
Transport Canada emphasized their right whale surveillance program, utilizing visual and audio detection tools to protect the whales from collisions. The department underscored the importance of employing the latest scientific research, monitoring data, and stakeholder feedback to inform and enhance their protection measures for the North Atlantic right whales.
