Dolphins are aquatic mammals who must surface to breathe air and are a type of cetacean. They are also notorious for being socially skilled, intelligent and joyful creatures. There are over 40 dolphin species in the world but over the past decade, an alarming proportion of dolphin species have been classified as ‘endangered’ around the globe. Why are dolphins endangered in the first place and what is being done to save endangered dolphins?
How is Extinction Measured?
The International Union for Conservation of Nature (IUCN) established a Red List in 1964 which has since evolved to become one of the world’s most comprehensive information sources on the global extinction risk status of different species. The List was conceived by Peter Scott (who also played a prominent role in the creation of WWF) and since then, it has been respected as a credible source of information relying on scientific data.
What are the Drivers?
When you think of dolphins, they are often pictured in seas and oceans. Of course, they can reside in saltwater, but certain species also live in freshwater. River dolphins such as the Amazon River dolphin (boto) and the South Asian river dolphins only live in freshwater rivers and lakes. Whatever their habitat, dolphins are important to the ecosystem in the sense that they are apex or top-level predators, controlling fish, squid and other populations to maintain the balance of the ecosystem.
The main drivers of dolphin endangerment can be narrowed down to two key categories: climate change and human activities. But there are other key factors threatening the survival of many dolphin species.
Firstly, the sheer speed at which the climate is changing could mean that dolphins may not have time to adapt. Sea level rise, a warming climate, ocean acidification and the loss of icy polar habitats are directly influenced by climate change and will impact dolphin species around the world. Climate change is expected to be the main cause of mass extinctions in the 21st century (have you ever heard of the Sixth Mass Extinction?) On top of a rapidly changing habitat, dolphins’ prey is rapidly reducing in numbers.
The other primary cause of dolphin endangerment are human (or ‘anthropogenic’) activities. This often includes fishing, river traffic and pollution – these are described in more detail below.
Fishing activities have played a huge role in the reduction in dolphin population over the years. The obvious reason is that as aquatic habitats are overfished in an unsustainable way, this reduces the prey available for dolphins. However, another huge threat to dolphins is ‘bycatch’. This involves the entanglement of dolphins in fishing gear, and is estimated to cause at least 300,000 deaths per year. For example, in the Mekong River, a transboundary river that spans over China, Myanmar, Laos, Thailand, Cambodia, and Vietnam, the majority of Irrawaddy Dolphin deaths have been caused by entanglement in gillnets ̶ ‘curtains’ of fishing net that hang in the water. This has also been cited as the greatest threat to a number of ‘Critically Endangered’ dolphins including the Atlantic Humpback Dolphin, the Baiji Dolphin (soon to be extinct, with the last documented sighting dated 2002), and the Maui Dolphin.
Chemical and noise pollution are also influential in the extinction of dolphins. Dolphins rely on pulsed tonal sounds for communication, navigation and hunting and, therefore, underwater noise from boat traffic and sonar can interrupt their ability to survive.
Other human activities that have become detrimental to dolphin populations include large-scale hydro construction projects like dams and irrigation bridges that have left South Asian River dolphin populations fragmented, and deliberate killings of the Amazon River dolphin for fish bait and predator control.
The Amazon River dolphin is becoming vulnerable due to dams and contamination of their habitat. Photo by Aqua Expeditions
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Television programmes like the BBC’s Blue Planet have played a significant role in raising public awareness of climate- and anthropogenic-driven impacts on the oceans and their inhabitants.
On an individual level, we can all make small changes such as reducing our single-plastic consumption, reducing the energy use in our homes, and ditching the car more often to minimise our carbon footprint and help slow down the effects of climate change. Also, bringing up issues about climate change and sustainability in discussions can help to spread the word.
Another individual action to take is to reduce seafood consumption, or at least to consider the impact that the fish you’re eating has on endangered dolphins’ survival. Eco-labels are one way to educate yourself about the food that you’re eating. However, it can be difficult to figure out the reliability of certain labels and there is often mixed messaging about their consistency (for example, Netflix’s Seaspiracy accused the Marine Stewardship Council’s “blue tick” label as certifying fisheries with high levels of bycatch in 2017, which you can read the MSC’s response here).
At a larger-scale, conservation efforts are being made to restore dolphin species around the world. For example, a study from 2016 developed biodegradable fishing nets to tackle issues such as ghost fishing; however, the authors explained that more research is needed as “there remain many uncertainties, challenges and knowledge gaps that have to be solved before we are able to draw firm conclusions about the overall benefits of these materials in driftnet fisheries”. Nonetheless, biodegradable netting could become a feasible alternative in the future.
In addition, by 2030 WWF aims to have stopped the decline of river dolphin populations in Asia and South America by tackling major systemic threats. Finally, ongoing research to determine effective locations to expand protected areas in Europe are discussed in this study from 2021.