A recent research study discovered that critically endangered North Atlantic right whales are feeding closer to the ocean’s surface at night, which raises the danger of them being hit by boats.
The study, released this month in the peer-reviewed journal PLOS One, highlighted the occurrence of nighttime surface feeding in North Atlantic right whales. These findings offer new insights that could aid in preventing fatal collisions between the whales and vessels.
The primary author of the paper, 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 in the southern Gulf of St. Lawrence.
During the summer, a segment of the North Atlantic right whale population, estimated at around 384 whales, congregates in the Shediac Valley to feed. Kirkham utilized the tags to capture video footage and gather data on the whales’ movements and swimming directions.
By analyzing the video footage, Kirkham observed the feeding behavior of right whales during the day. He described how the whales slow down when they open their mouths, requiring them to exert more effort by moving their tails more vigorously.
To address the challenge of identifying nighttime feeding behavior visually, Kirkham trained a machine learning algorithm using his observations. The data revealed that whales feed at a depth similar to that of large vessels at night, heightening the risk of collisions.
Although right whales typically feed closer to the seabed during daylight hours, they follow their food source, zooplankton, higher up in the water column at night.
The study emphasized that collisions with ships and entanglements in fishing gear are the primary causes of death among the whale population. The insights from this study could guide conservation efforts for the whales, currently managed by Transport Canada and Fisheries and Oceans Canada.
Fisheries and Oceans Canada stated that its conservation measures focus on preventing whale entanglements in fishing gear and enforcing seasonal fishing closures. The department suggested that the study could help in tailoring management strategies to safeguard North Atlantic right whales.
Transport Canada, on the other hand, implements speed limits and enforces 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. However, Kirkham noted that the tagged whales spent a significant portion of their feeding time outside the exclusion zone, making them vulnerable to ship traffic.
Transport Canada mentioned having a right whale surveillance program that utilizes visual and audio detection tools to protect the whales from collisions. The department emphasized using the latest scientific research, monitoring data, and stakeholder feedback to shape its protection measures.