A recent research study has discovered that the critically endangered North Atlantic right whales are engaging in nighttime surface feeding, a behavior that increases their vulnerability to boat strikes. The findings, published in the scientific journal PLOS One, shed light on the nocturnal feeding habits of these whales and offer insights that could help prevent fatal collisions with vessels.
The study, led by Jay Kirkham, a PhD student at Dalhousie University, in collaboration with the U.S.-based non-profit Ocean Alliance, involved tagging 23 North Atlantic right whales in the Shediac Valley, located in the southern Gulf of St. Lawrence. This area serves as a feeding ground for a portion of the estimated 384-strong population of North Atlantic right whales during the summer months.
The tags attached to the whales captured video footage and data on their movements and swimming patterns. By analyzing the video recordings, Kirkham observed the whales’ feeding behavior during daytime hours. He noted that when the whales feed, their mouth acts like a large parachute, slowing them down and requiring increased effort in swimming by kicking their tails vigorously.
To address the challenge of identifying nighttime feeding behavior, Kirkham developed a machine learning algorithm based on the observations. The data revealed that the whales feed at a depth similar to that of large vessels at night, heightening the risk of collisions. While the whales typically feed near the sea floor during the day, they move higher up in the water column at night to follow their food source, zooplankton.
Collisions with ships and entanglements in fishing gear are identified as the primary causes of mortality in the North Atlantic right whale population. The study aims to provide valuable insights for implementing conservation strategies to protect these whales.
Fisheries and Oceans Canada highlighted their focus on preventing whale entanglements and enforcing seasonal fishing closures to safeguard the North Atlantic right whales. Transport Canada, on the other hand, enforces speed restrictions and implements a vessel exclusion zone in the Shediac Valley during the summer to reduce the risk of boat-whale collisions. However, Kirkham noted that a significant portion of the tagged whales spend a quarter 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 mitigate collision risks. The department relies on the latest scientific research, monitoring data, and stakeholder feedback to inform and enhance protection measures for the whales.