Submerged gill nets, lines running between lobster or crab pots, and other fishing gear can have tragic, unintended consequences for right whales. When the tough lines lodge in a whale's mouth, or wrap around its flippers or tail, they can cut into the whale's skin or restrict its movement.
Reported deaths from entanglement amount to about 1.5 whales per year, and entanglement is so common that some 75 percent of living whales bear scars. Some carry tangled fishing gear with them for years afterward. Whale biologists can in some cases cut the gear loose, but such delicate work with large, diving animals is dangerous for people and whales alike.
Whales that survive an entanglement may not get free of the gear they carry, and die later after slowly starving to death. Often these whales lose so much body fat that they no longer float. Since they don’t wash up on beaches, it’s especially difficult to keep track of how many whales die from entanglements. Suggestions for keeping fishermen from unintentionally harming whales include switching to lighter line--heavy enough to do its job, but frail enough to break if it snares a whale--or less buoyant line that runs along the sea floor instead of floating suspended in the water.
More about threats to right whales
More resources: stopping entanglements
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