At least 10% of dolphins and porpoises were found to have ingested ocean plastic, which can cause fatal tears and blockages. Of equal concern is ocean plastic ingestion by their prey species, which has lasting implications for the entire food chain.
Plastics in the environment can easily absorb a class of chemicals called POPs, or persistent organic pollutants. POPs have a high lipid solubility, which means they are attracted to fats and oils.
When an animal ingests plastic, the chemicals absorbed by the plastic can pass through cell membranes and bioaccumulate, or build up, in the animal’s fatty tissue over time. POPs can interfere with body processes, be passed onto offspring, and impact reproduction.
Dolphins and porpoises are affected not just by the plastic they ingest, but by the plastic their prey species consume as well. Toxins become concentrated in animals higher up the food chain in a process called biomagnification. So dolphins and porpoises are also consuming all of the toxins that have built up in their prey species.
Plastics have been found to accumulate POPs at concentrations of up to 1 million times greater than what you’d find in the surrounding seawater, which is accelerating the rate at which animals like dolphins and porpoises are affected.
Lost and abandoned fishing gear makes up around 10% of all ocean litter. Every year, more than 300,000 dolphins, porpoises, and other cetaceans die after becoming tangled in it. Some animals drown when they can’t reach the surface while others remain tangled in the gear and eventually succumb to infections or starvation.
While some dolphins and porpoises are specifically targeted by fishermen, the vaquita is not. It’s actually bycatch that’s the biggest threat to their survival. They often become entangled in the illegal gillnets of poachers who are hunting the equally endangered totoaba fish. The totoabas’ large swim bladders have a high value on the Chinese black market and provide enough financial incentive to make the risks of poaching worth it to the offenders. The vaquitas’ critically endangered status is an unfortunate consequence of illegal fishing that targets another species entirely.
Dolphins and porpoises use sound to find food, communicate, and travel. They listen the way we see. Sound is crucial to their survival, but humans are making the ocean louder.
Noise pollution interrupts normal behavioral patterns and drives dolphins and porpoises away from crucial habitats. It can also cause serious injuries and can even be fatal.
For example, the oil and gas industry uses seismology to find underwater reservoirs of oil and gas, which directs loud pulses of noise at the seabed. The military uses powerful underwater sonar. It can travel hundreds of miles and retain an intensity of 140 decibels for up to 300 miles. For reference, the world’s loudest rock bands top out at 130 decibels.
As technology makes coastal and marine areas more accessible to tourists both physically and economically, increased boat traffic is also adding its own din to the noise that’s polluting the ocean.
Global climate change is also changing the native habitats of dolphins and porpoises, particularly those found in the Arctic / Sub-Arctic and Antarctic / Sub-Antarctic regions of the world, where warming is having the biggest impacts. Shifting weather patterns and changes in the seasonal patterns of prey species are having significant negative impacts on dolphin and porpoise populations.
Dolphins have evolved for over 50 million years. Even though they’re mammals, they’ve adapted perfectly to life at sea. They have large, complex brains, are self-aware, and develop close relationships with family and other pod members.
Yet these intelligent creatures are routinely captured, harassed, slaughtered and sold into captivity around the world – all in the name of profit. Captivity is a billion dollar industry, but everything we’ve learned from dolphins shows us that they don’t belong in concrete tanks, performing tricks for our amusement.
Our work with Ric O’Barry’s Dolphin Project will help raise awareness about the issues facing dolphins and protect their populations around the world. By purchasing a Dolphin Bracelet, you’ll remove one pound of trash from the ocean and coastlines. You’ll also support Ric O’Barry’s Dolphin Project and their efforts to protect dolphins and keep them safe and free.
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