Whale Bycatch: Killing Species by Accident

A pod of blue whales weaves through Pacific waters, each slender body exceeding the largest dinosaur. 

A humpback enchants the ocean as his midnight melody travels for miles. 

A nylon trap twists around a right whale, anchoring her underwater. Eventually, fishermen in pursuit of a different species find and discard her body to the dark sea. 

Commercial fishing is one of whales’ greatest threats through entanglement in inactive fishing gear and whale bycatch—the unintentional capture of whales. 

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Bycatch directly threatens whales 

We dump enormous nets and scatter hundreds of thousands of traps across whales’ feeding grounds and migration routes. Whales cannot easily detect these materials. What was once an undisturbed journey through open ocean has become a near-invisible maze. At least 300,000 whales, dolphins, and porpoises die every year after entanglement in fishing gear. That is equivalent to 800 deaths each day. 

And that’s just the death toll we know. 

It’s challenging to monitor industrial fishing since it takes place so far offshore. This means marine animal mortality is often unchecked. Several whales die out at sea, out of sight, and off the record.  

Whales must resurface to breathe, but entanglement in fishing gear can keep them stuck underwater too long. Too often, as whales struggle against a trap that wasn’t set for them, they run out of air until they suffocate. 

Not all whale bycatch mortality is immediate. Many entangled whales manage to escape fishing gear but not unscathed. Ropes cut into their skin, sometimes to the bone, leaving painful wounds. Some whales heal, some succumb to infection. Some never fully untangle themselves and swim away with their mouths wired shut. They die the tedious death of starvation. 

Still, some whales survive for years with fishing gear tangled around their tails, fins, and other body parts. Commercial lobster traps have a buoy on the surface and a vertical rope extended down to cages on the ocean floor. Whales can escape after becoming entangled in these ropes, but sometimes part of the line remains wrapped around their bodies with the cages still attached. Whales must then drag this burden through the ocean, expending more energy simply to swim. This is especially significant for a female whale. She may be left with too little energy to successfully reproduce. This exacerbates population recovery challenges for already-endangered whale species. 

Both the North Atlantic right and Arabian Sea humpback whales are endangered, and the commercial fishing industry is their number one threat. As many as 80% of right and humpback whales have been entangled in fishing gear at least once. Researchers once assumed large whale species, such as blue and fin, were mostly spared from whale bycatch since they are stronger and live farther offshore. However, we now know about 60% of blue whales and 50% of fin whales in Canada’s Gulf of St. Lawrence show evidence of entanglement in nets. These are stark differences from the previously assumed 10% entanglement rate for the two species. It seems no whale is safe from the fishing industry’s reach. 

Whales are necessary to their ecosystems  

If whales aren’t safe, neither are their ecosystems. 

Ocean mixing is the process by which nutrients and heat are distributed throughout water. Marine vertebrate activity alone generates one third of all ocean mixing. They are nearly as powerful as tides and wind. Whales contribute by creating a vertical “whale pump.” Each time they dive and resurface, they move nutrients that may otherwise be stuck in deeper water or the ocean floor closer to the surface. In this way, whales support organisms ranging from aquatic plants to sea birds. They also move nutrients horizontally across the ocean during their migrations. 

In addition to ocean mixing, whales release fecal plumes rich in iron, nitrogen, and phosphorous–all necessary nutrients for phytoplankton. These microscopic marine algae are a foundation for marine food webs. The boost whales give to phytoplankton populations ripples up entire food chains to krill, fish, and large mammals including other whales. And people. Our seafood availability depends, in part, on whales. 

Another, perhaps more surprising, service whales provide is curbing climate change. Phytoplankton are photosynthetic, so they absorb carbon dioxide. When they die, 20-40% of the carbon inside them sinks to the ocean floor. Therefore, by increasing phytoplankton stocks, whales increase carbon dioxide removal from the atmosphere and storage under the sea. Additionally, when whales die and settle to the ocean floor, their bodies act as massive carbon stores with slow rates of decay. If recovered to pre-industrial populations, large baleen whales could have the carbon storage capacity of 110,000 hectares (about 272,000 acres) of forest.

Whales are unquestionably important to their ecosystems. Even in places such as the Southern Ocean, where whale populations were decimated but are now recovering, the local food chain is still reeling. If whale bycatch continues, or worsens, how many more places will suffer? How do we help? 

Strategies to reduce whale bycatch

What does it take to protect whale populations? It takes the world. Both whales and the fishing industry exist internationally, so international conservation action is necessary. 

One strategy to decrease bycatch and entanglement is using new fishing technology. Some lobstermen are now using traps that only release a vertical line through the water column during retrieval or traps that float to the surface with no line involved at all. 

Transitioning to these and other new harvesting strategies requires time and financial investments that many fishermen and industry stakeholders oppose. People’s livelihoods are on the line. Nation’s must enforce new fishing strategies but in ways that help fishermen transition to the new strategies or entirely new jobs. One way is to subsidize new technology. While another tax bill may sound undesirable, there is a much bigger price involved. Without industry-wide changes, some species, such as North Atlantic right whales, will be swept away to extinction. 

We can also reduce whale bycatch by going straight to the source. Our current global seafood consumption exceeds all sustainability quotas. Decreasing this demand is crucial to whale, and all marine, conservation. 

It’s important to remember, for most of us, we merely desire fish. The ocean requires whales. They move nutrients, support the food chain, and curb climate change. All we have to do is let them live. 

As an individual, it can be intimidating to demand the world look out for its whales. But just as a single whale can support the lives of countless ocean creatures, you can influence an entire species’ survival. Even a drop in the ocean creates ripples. 

Report Entangled Whales in the United States
  • 1-877-SOS-WHALE (767-9425)
  • United States Coast Guard on VHF CH-16
  • Dolphin and Whale 911 app (for Apple devices)
  • NOAA Fisheries (listed by region)
Report Stranded Whales Across the World
Sign Petitions
Support Organizations
Submit Comments
  • International Whaling Commission
  • National lawmakers
  1. “A Whale of an Effect on Ocean Life: The Ecological and Economic Value of Cetaceans.” Animal Welfare Institute, 2017, https://awionline.org/awi-quarterly/fall-2017/whale-effect-ocean-life-ecological-and-economic-value-cetaceans

  2. Briggs, Helen. “Whale threats from fishing gear ‘underestimated.’ ” BBC, 9 Feb. 2021, https://www.bbc.com/news/science-environment-55987350

  3. McCarthy, Joe. “Endangered Whales Are Being Killed by Fishing Gear. New Technology Could Change That.” Global Citizen, 8 Nov. 2019, https://www.globalcitizen.org/en/content/ endangered-right-whales-fishing-gear/

  4. “Threats.” WWF, https://wwf.panda.org/discover/knowledge_hub/endangered_species/cetaceans/ threats/

  5. “Whale Entanglement – Building a Global Response.” International Whaling Commission, https://iwc.int/entanglement

  6. Zuckoff, Eve. “Ropeless Lobster Fishing is Good News For Endangered Whales.” NPR, 19 Feb. 2021, https://www.npr.org/2021/02/19/969559244/ropeless-lobster-fishing-is-good-news-for-endangered-whales


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