Large Whale Entanglement Mitigation

Photo: Jerry Conway. Organization: Campobello Whale Rescue Team.

The North Atlantic right whale, a species restricted to the coastal northwest Atlantic, numbers fewer than 440 individuals and has been declining since 2010 (Pace et al. 2017; Pettis et al. 2017). Entanglement in fishing gear, especially in fixed gear like pots and gillnets, is the leading cause of human-induced mortality and serious injury, occurring at a rate that is not sustainable for maintaining a viable population. Entanglement mortalities and serious injuries consistently exceed the regulatory limits of Potential Biological Removal rate set under the Marine Mammal Protection Act (presently set at 1 whale per year allowed to be taken by human activities; see NOAA’s 2016 Stock Assessment Report for North Atlantic right whales). In 2017, 17 North Atlantic right whales (Eubalaena glacialis) were found dead in the U.S. and Canada, compared with an annual average of 3.8 per year. As of October 16, 2018, there have been three dead right whales and one serious injury observed in 2018; one mortality and the serious injury were both entanglement related, another dead whale was too decomposed to perform a full necropsy; and the third showed markings consistent with entanglement injuries but a full investigation has not yet been performed. There have also been three entangled right whales with attached gear and one with severe entanglement injuries documented from July – Aug 2018. One was found in the Bay of Fundy and had last been seen without gear in the Gulf of St. Lawrence. It was disentangled but its fate is uncertain. Two were entangled in the Gulf of St. Lawrence, one is still entangled, with its fate unknown, and one apparently shed the gear but its baleen was damaged and its fate is also unknown. The right whale with severe injuries was a 2 year old seen in June in the Gulf of St. Lawrence without injuries and in July in the Gulf of St. Lawrence with injuries. As a result of this elevated mortality rate, NOAA Fisheries declared an Unusual Mortality Event for this species. Just as worrisome, the rate at which calves are being born has fallen to historic lows, with just five calves observed in 2017 and none in 2018. In short, to avert the near-term possibility of extinction of this species, we urgently need to eliminate the threat to these whales from entanglements in fishing ropes.

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Project PI(s): 

Scott Kraus, Tim Werner, Amy Knowlton
Research Program: 
Fishery Animal Interactions