About Whale Entanglements

How Do Whales Become Entangled?

Whales become entangled in a variety of ways. In northern California, the most common entanglements occur when whales encounter the ropes that attach buoys on the water's surface to crab pots or spot prawn traps on the ocean floor. These long ropes are difficult to see underwater. One common entanglement occurs when a whale catches these ropes across their mouth while laterally lunge feeding for fish. Filter-feeding whales have baleen in their mouths, and when the rope slips to the back of the mouth, it often becomes caught behind the baleen in the gape. Whales have no way of pushing the line out of their mouths when the rope ends up in this position, and the line often becomes embedded in the tissue, sometimes even down to the bone, becoming set due to the drag created by the entangling gear as they swim. As one can imagine, it's incredibly painful, and often hinders the whale's ability to feed and swim.

A crab pot is retrieved from the ocean floor after a humpback whale became entangled in its line. 

Other reasons for entanglement can be related to social or reproductive behavior when whales have "more important agendas on their minds" and run into gear when not paying attention to their surroundings because they are focused on the "task at hand.” Also, these are highly intelligent animals who are curious about their environment. It could be that a curious whale is investigating a long line running through the water column and when they accidentally hit that line with long appendages (pectoral flippers and tail stocks/flukes) they may react strongly and quickly, leading to an entanglement.

Elsewhere in the world, whales and other marine mammals become entangled in many different types of material such as longlines, gill nets, monofilament lines, seine nets, and everyday trash like packing straps, strings, six-pack holders, even toilet seats.

What Kinds of Whales Do We Rescue? How Many?

Humpback whales are darker in color, have long pectoral flippers and a more pronounced dorsal fin than gray whales.

Blue whales, fin whales, minke whales, and even a killer whale have been entangled in recent years along this coast. However, most often we encounter entangled humpback and gray whales in our region. Humpbacks move into the area (from Mexico and South America) during the summer months to feed within the highly productive, but variable California Current ecosystem. Gray whales are seen traveling south from feeding grounds in Alaska to breeding and calving grounds in Mexico from November through February. They then make the opposite migration from south to north from March to June with common sighting of mothers with calves traveling close to shore.

Gray whales are a lighter gray color, do not have a pronounced dorsal fin, and typically have more visible barnacles and other parasites.

The numbers of reported and unique entanglement events has increased dramatically in recent years. In our region, one to three a year was the norm fifteen years ago. In 2015, the number of reported entanglements in California exceeded 25 and for the region (West Coast, Hawaii, and Alaska) the number exceeded 65. The reasons for the increased reports includes whale populations that continue to recover from lows at the end of commercial whaling in 1972 and increased activities from crab, prawn, and swordfish fisheries. Another reason may be from effective outreach programs that educate ocean users on how to report entanglements. 

What Determines Success?

While we can’t save every whale, we do our best to respond to as many as we can. Our greatest successes come when the reporting parties call the hotline at 877-SOS-WHALE, give a detailed report of the entangled whale they’re seeing, take and send photographs, and stay with the whale at a safe distance until one of our response boats is able to meet up and take over. If no one is able to stay with the whale, it is highly unlikely that we’ll be able to find it again, unless it is grounded. However, valuable information is gained by simply making a report and there are times when we consider this alone as a success. Learn How to Report an Entangled Whale »

What Can Be Done to Prevent Entanglements in the Future?

Though most entanglements involve commercial fishing gear, we certainly do not place blame on the fisherman. Instead, we are working to develop strong relationships with this group of professionals, to share perspectives on how to mitigate this problem going forward. Additionally, we enlist the help of the experts: the fisheries, fishing gear manufacturers, local fishermen, entrepreneurs, other marine mammal rescuers, and the government. We hold joint information and training sessions where we brainstorm modifications to gear, fishing methods, and locations. We hold educational events to inform the community regarding how they can help reduce the amount of debris in the ocean. And we look to you to help us spread the word about these important issues, as we all work together to make the ocean a safer place for all who inhabit it.