ifaw-led research confirms North Atlantic right whale mortalities driven overwhelmingly by man-made causes

According to IFAW Veterinarian Dr. Sarah Sharp, “Between 2003 and 2018, of all the causes identified, no adult or juvenile North Atlantic right whale deaths were a result of natural causes. Not even one.” This is one of the startling points to note as a result of a new scientific paper led by Dr. Sharp and a multi-agency team which was released today in the journal Diseases of Aquatic Organisms.

Out of a total of 70 whales, the cause of death was definitively determined for 43. Of those, nearly 90% died as a direct result of two anthropogenic causes---trauma resulting from entanglement in line and marine vessel collisions. 

Both of these causes of death are horrific. Entanglement caused immediate, traumatic drowning events in some cases and prolonged, painful deaths in others resulting from constrictive wraps of line. Despite mitigation efforts, entanglement deaths increased from 21% to 51% from studies dating back to 1970. Wrapping around the whale’s flippers, tail, head, or mouth, entangling line caused anything from deep lacerations to partial amputations of the flippers. Vessel collisions also caused fatal trauma including massive skull, jaw and vertebral fractures, as well as deep chop wounds that led to severe blood loss and tail amputations. 

The North Atlantic right whale inhabits one of the oceans’ most industrialised corridors along the coastline between Florida and the Gulf of St. Lawrence in Eastern Canada. Given the level of human activity in this area, the lethal threats posed by both entanglements and marine vessel collisions are especially high. This is all the more concerning given that only approximately 411 North Atlantic right whales remain in the world today. Though commercial whaling for the right whale was banned in 1935, entanglement and vessel collisions continue to drive a strong decline in their population.

According to Dr. Sharp, “This study demonstrates unequivocally that these animals are unable to live full, productive lives because they are dying prematurely as the result of human activities. The high number of deaths is not sustainable for this small population. The good news however, is that these mortalities are preventable if targeted and aggressive mitigation measures are enacted immediately by the US and Canada.”

Based on the results of their findings, Dr. Sarah Sharp and the team recommend employing ropeless fishing gear, expanding vessel speed restriction to include larger areas of right whale habitat, and implementing management strategies like fisheries closures. 

Sharp concludes that “With a population this small and declining birth rates, the loss of even one individual represents a major blow to the recovery of the species as a whole. The data tell a very compelling story, one which we need to turn around immediately to bring the species back from the brink of extinction.”