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Whales, dolphins and fishing

The biggest killer of whales and dolphins across the world is accidental capture in fishing gear, or ‘bycatch’. Several hundred thousand whales and dolphins are estimated to die each year as a result of bycatch. Many others are injured and their bodies bear the tell-tale marks of having been caught in fishing gear.

How big is the problem?

There are very few parts of the ocean where fishing takes place that this is not a serious issue. But, the extent of the threat, the species concerned and the fisheries involved vary from place to place and generally, are not well documented.

To most individual fishermen, a whale or dolphin accidently encountering their gear is an infrequent event. No fisherman wants to catch a whale or dolphin by accident, and it is an upsetting event. But, given the size of the global fisheries, in 2006 it was estimated that the numbers of whales, dolphins and porpoises caught each year is in the hundreds of thousands.

Harbour porpoises
Harbour porpoises

It’s a horrible way to die

Most dolphins trapped underwater by fishing gear die of asphyxiation (suffocation). While the time it takes for individuals to die in this way varies, it is likely that many are subjected to a longer period of suffering and stress than would be considered morally unacceptable in a slaughterhouse. Whales, dolphins and porpoises can hold their breath for long periods of time. The smallest porpoise can remain underwater for over five minutes between breaths, and sperm whales can dive for over an hour between surfacing. The damage seen on bycaught individuals shows that many of them struggle desperately to escape from their entrapment, sustaining horrific injuries in the process.

The severe injuries regularly seen in bycaught whales, dolphins and porpoises are evidence of the suffering victims go through. Rope and netting often cause cuts and abrasions to the skin, tightening as the individual struggles and cutting deeper into the flesh. In extreme cases, fins and tail flukes can be totally or partially amputated by the tightening gear. Bodies of bycaught dolphins are commonly recorded as having broken teeth, beaks or jaws and extreme internal injuries.

Large whales who become entangled in fishing gear have been found with severe lacerations deep into their blubber and even into their bones. As large whales are often powerful enough to swim away and pull the gear with them, the rope continues to tighten and cut into their body over time, often resulting in a slow and painful death that can last months. 

For a more in-depth understanding of the issue, you might want to read our report ‘Shrouded by the Sea’ [WEB LINK]. This study, based on research by the University of Bristol, reveals the harrowing details of how whales and dolphins slowly meet their death, many suffering extreme injuries in what can be a very drawn out underwater struggle.

Talking points

  • Hundreds of thousands of whales, dolphins and porpoises die in fishing operations annually.
  • Death in fishing gear can be slow with considerable suffering.
  • Bycatch has pushed vaquitas in the Gulf of California and Maui dolphins in New Zealand to the brink of extinction.
  • The survival of harbour porpoises in the Baltic Sea is threatened because of static nets.
  • Most endangered North Atlantic right whales and Gulf of Maine humpback whales have evidence of entanglement in fishing gear.
  • Fishermen are not intentionally capturing whales and dolphins

What is WDC doing?

WDC campaigns to reduce and, where possible, eliminate whale and dolphin bycatch in fishing practices.

  • We work on government stakeholder teams where we help to develop regulations to reduce this threat.
  • We research vulnerable whale, dolphin and porpoise populations.
  • We campaign to raise awareness and let people know what they can do to help.

What can I do?

With the exception of tuna, it’s almost impossible to know if the fish we eat comes from a fishery with a bycatch issue. This is because bycatch is not adequately considered in existing ‘ecolabels’. The best way to ensure that your canned tuna is the most dolphin friendly it can be is to buy canned tuna caught with a pole-and-line, or one-by-one fishing, where tuna are caught by fishermen one at a time, using one hook and one line. This traditional and much more selective fishing method has a significantly lower level of bycatch. Clear labelling on tuna cans is required, with labels including the tuna species in the can, where it was caught and the fishing method used. Look for labels that indicate your tuna purchase was caught one-by-one or by pole-and-line fishing; and if you are unsure ask your retailer or look online, there’s plenty of helpful information now available. It’s more tricky with other seafood but ultimately, it’s important that consumers seek out the most sustainable products available.

Some seafood guides are available, and bycatch might be a consideration in these, for example: and

WDC is calling for governments, regulatory bodies and fisheries stakeholders to act urgently and decisively to end this unacceptable suffering of whales, dolphins and porpoises. This will require the collection of better data and changes to the way fish are caught including gear modifications, gear marking, and possible fishing restrictions to reduce this threat.