Did you know that at least one third of the fish that are caught in commercial fishing nets are thrown back into the sea, dead or dying?  Known as bycatch, this may be because they are a fish species that is not valuable to the fishing industry, but it can also be because they are mammals that just happened to get caught in the nets.  Bycatch when fishing for tuna in particular is one of the leading causes of death for dolphins and other cetaceans, and their numbers are in steep decline as a result.

“Between 1950 and 2018, the fishing industry unintentionally caught around 4.1 million dolphins”, says Dr. Putu Liza Mustika, who worked on the study. A research team—led by Dr. Charles Anderson of the Maldivian Manta Marine organization—looked at bycatch rates in the Indian ocean to draw its conclusions.

They estimate that the dolphin population in the Indian Ocean stands at 13 percent of what it was in the 1980s. Mustika notes that the figures in the study are “ball-park figures,” and therefore have a lot of uncertainties. But what they do confirm is the magnitude of the problem.

The study includes a number of dolphins and whale species, including Indo-Pacific bottlenose dolphins, humpback, Risso’s, and common dolphins. The study states that although tuna catches are increasing, dolphin bycatch stagnated in the 1990s. [It] has since declined, and is therefore unsustainable and impacting populations, according to Dr. Sarah Dolman from Whale and Dolphin Conservation (WDC).

It’s not just dolphins that end up as bycatch. The World Wildlife Fund (WWF) says, “entanglement in fishing gear is the leading threat for whales and dolphins around the globe. [It’s] estimated to cause at least 300,000 deaths per year.”

According to Dolman, fishers caught 75 percent of toothed cetaceans in gillnets in the past 20-plus years. Sixty-four percent of baleen whales have ended up as bycatch in the same time period, as well as 66 percent of pinnipeds (that’s animals like seals, sea lions, and walruses).

Dolman notes that authorities have taken some action to mitigate the situation, including fishing bans and gear modifications. “There is much that can be done to better monitor, mitigate report, and enforce dolphin bycatch.” She adds that the Food and Agriculture Organization of the United Nations (FAO) is currently producing best practice guidelines to prevent and reduce marine mammal bycatch. She notes: “this would be a good place to start.”

However, all the fishing regulations in the world will not prevent these beautiful creatures from dying as long as there is a high demand for fish, especially tuna.  One thing you can do is to give up eating fish, or switch to vegan substitutes for fish products.  We wrote last month about some of the new vegan seafood brands that are available.  It’s also easy to make your own “tuna salad” from chickpeas.  See recipes