How does entanglement happen, exactly?


This illustration shows only the set up of a trawl of trap-style fishing gear, when in truth, marine mammals are entangled in a whole host of different things we place in the oceans. ©Graphic Services, Woods Hole Oceanographic Institution

The majority of baleen whales feed by either opening their mouths after targeting a specific prey and taking in a large amount of fish plus sea water, then forcing the excess water out through their baleen, or by actively swimming with their mouths open while straining the water. The latter is the method of feeding used by the North Atlantic Right Whale.

Credit Anderson Cabot Center for Ocean Life, BelleQuant, New England Aquarium and Duke University- Pratt School of Engineering

While entanglement is not limited to this species, they do tend to pick up a great deal of vertical line from the water column. With eyes placed on the sides of their heads, these whales have limited vision directly in front of them, similar to horses. Lastly, North Atlantic Right Whales have an unusual downward angled curve to the back of their lips, creating the perfect anchor space for any rope they may accidentally sweep up in their search for food.

Gray whale trapped in seine net. ©OneGreenPlanet.org

Other causes of entanglement:

Seine nets, monofilament nets and lines, and mooring lines are just a few of the underwater threats faced by dolphins, porpoises, sea turtles, sharks, and pinnipeds (seals, sea lions) as well as a whole host of whales, both large and small.

-Kim Sawicki December 2018

One thought on “How does entanglement happen, exactly?

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s