Hundreds of thousands of marine mammals are killed in fisheries each year. Of the 13 whale, dolphin, and porpoise populations listed as Critically Endangered by the International Union for Conservation of Nature (IUCN), 11 are declining due to bycatch in gillnets. 

Purse seine fisheries can also incidentally capture marine mammals, and there have been population-level impacts associated with the intentional setting of purse seine nets around dolphins in tuna fisheries in the eastern tropical Pacific Ocean since the 1960s. Even with dropping mortality rates of dolphins in recent decades, as a result of increased awareness of this threat, dolphin populations are not showing signs of recovery. 

For larger marine mammals, static rope gear using pots and traps is a devastating problem. Lethal entanglement of baleen whales, such as the endangered North Atlantic right whales and humpback whales, is one of the most awful forms of human-caused mortality in any wild animal, often lasting for long periods of time and causing immense suffering.

All kinds of marine mammals can become entangled by trawl gear when swimming to forage or migrate, and species that forage near the seafloor can also be captured or entangled in netting or tow lines. 

The following are some best practices for reducing unintentional interactions with marine mammals. (As our initiative develops, we will expand this list to include more best practices for all types of fishing gear.):

  • Using ropeless gear to prevent entanglements
  • Avoiding fishing in known marine mammal hotspots
  • Using circle hooks, which are wider and more difficult for marine mammals to bite on
  • Communicating within and among fleets to determine where marine mammals have been sighted
  • Using “weak” hooks that bend or break when a certain amount of pressure is applied
  • Increasing observer coverage on fishing vessels to 100 percent (human and electronic) coverage
  • Using acoustic alarms, or pingers, which may help marine mammals avoid entanglement in certain circumstances
  • Avoiding fishing gears, such as gillnets, known to present the highest risk to marine mammals. 

The Canada Gulf of St. Lawrence snow crab – pot/trap fishery improvement project (FIP), which is led by New Brunswick and Quebec Seafood Processors and Fishermen Associations, aims to reduce impacts on Critically Endangered North Atlantic right whales in Canada’s largest snow crab region. The fishery’s Marine Stewardship Council (MSC) certification was suspended in 2018, due to increasing mortalities of right whales that become entangled in fishing gear, an emerging problem driven in part by the impacts of climate change on the whales’ migration patterns. The FIP participants are conducting trials with different types of ropeless gear to reduce the risks to right whales and other non-target species in the Gulf of St. Lawrence.

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