Blue shark swimming in the blue as the sun rays filter through the water. This image was taken at a dive site called Azores Banks.

560405213

Blue shark swimming in the blue as the sun rays filter through the water. This image was taken at a dive site called Azores Banks.

Photo by: by wildestanimal

by wildestanimal

Shark Conservation is Essential to Tackle Climate Change

By: Robin Fearon

We depend on sharks: that’s just a fact. As predators, they regulate the ocean’s ecosystems and reduce carbon emissions, so preserving their numbers is a top priority.

July 12, 2021

Sharks are one of the oldest and most important species on Earth–their earliest fossils show that they were here 400 million years ago, well before trees laid down their roots.

Overfishing has reduced shark numbers globally by 71% since 1970. Researchers undertaking the largest-ever study of reef sharks found they were missing from waters they had previously inhabited in 58 countries. This drop is due to overfishing, but climate change has the potential to weaken shark numbers even further.

Bleached coral on the Great Barrier Reef outside Cairns Australia during a mass bleaching event, thought to have been caused by heat stress due to warmer water temperatures as a result of global climate change.

1214651199

Rising ocean temperatures not only affect coral, but sharks too.

Photo by: Brett Monroe Garner

Brett Monroe Garner

Rising ocean temperatures not only affect coral, but sharks too.

Warmer ocean temperatures caused by climate change are thought to have a role in outbreaks of skin disease found on white tip reef sharks in Malaysia’s coral reefs. Rising temperatures also increase the risk of baby sharks being born smaller and weaker, less able to survive to adulthood.

Scientists studying epaulette sharks from the seas around Australia and New Guinea found that warmer water sped up the shark’s growth process. Young hatched from their eggs early and were born exhausted. Epaulette sharks are known for their toughness and resilience, and researchers say other less-tolerant species, including those that give birth to live young, are also at risk.

748601717

Climate change is putting shark eggs at risk — causing them to hatch early.

Photo by: Cludio Policarpo

Cludio Policarpo

Climate change is putting shark eggs at risk — causing them to hatch early.

In global change hotspots like southeast Australia, the sea temperature is rising at three to four times the global average acidity is increasing and the amount of oxygen in the water is falling. How sharks respond to changes in their environment will be crucial, but the signs are not promising.

Moving to cooler waters and away from warming seas as their prey moves in search of its own food is one response. Great white sharks have moved 370 miles (600 km) northwards into California’s Monterey Bay waters that were previously too cold, disrupting ecosystems as they prey on local sea otters and salmon.

Scientists say it highlights the movement of marine animals towards the poles and the unpredictable and potentially damaging effects that follow. “These sharks–by venturing into territory where they have not historically been found–are telling us how the ocean is being affected by climate change,” said Kyle Van Houtan, chief scientist at the Monterey Bay Aquarium.

Another study in Western Australia simulated the extinction of tiger sharks due to rising sea temperatures and the knock-on effects that might have on local ecology. Dugongs, relatives of Florida’s manatees, are the shark’s prey and their numbers would increase, leading to overgrazing of seagrass.

Seagrass, Cenderawasih Bay, West Papua, Indonesia

521324740

The extinction of tiger sharks could have a chain reaction in the ecosystemleading to the overgrazing of sea grass.

Photo by: Reinhard Dirscherl

Reinhard Dirscherl

The extinction of tiger sharks could have a chain reaction in the ecosystemleading to the overgrazing of sea grass.

Delicate seagrass environments would not be able to regenerate quickly enough for other species that use it for shelter. The entire ecosystem would be disturbed and its biodiversity negatively affected. Plus, the seagrass meadows’ ability to act as a carbon sink would be wiped out.

Yet another species negatively affected by warming waters is the wide-ranging blue shark. Scientists have discovered that blue sharks don’t dive as deeply in warmer low-oxygen areas, leaving them exposed to capture by longline fishing boats.

Overfishing large fish like sharks, tuna and swordfish also increases the amount of carbon dioxide released into the atmosphere. Sharks and other big fish are made up of around 10–15% carbon. When they die naturally in the ocean, instead, they sink to the bottom, sequestering their carbon for thousands or millions of years. So preserving sharks actually cuts carbon emissions and weakens climate change.

For more on sharks, stream SHARK WEEK now on discovery+.

Next Up

The Highest Animal on the Food Chain: Megalodon Sharks

The now-extinct megalodon and its ancestors may have been "hyper apex predators," higher up on the food chain than any ocean animal ever known.

Sharks and Mermaids, oh my!

As I stood in waist-deep water, bouncing gently with each swell of the ocean, the two tourists next to me suddenly yelled “shark!” They retreated panicked toward the shore, as a kayaker nearby chuckled and shouted a quick lesson “Don’t worry, they don’t bite!”

Canada's Wildlife is in Hot Water

Uncharacteristically hot temperatures in Canada and the Pacific Northwest have left people searching for relief. But what about the wildlife? It is only getting warmer, and that has caused irreversible damage and tragic demise to over 1 billion sea creatures.

Shark Tracking is Protecting Endangered Species like the Great White and Tiger Shark

Scientists use a variety of methods, from acoustic tracking to body cams, to collect vital information on where sharks live, their numbers, their behavior, and environmental health.See scientists at work using these technologies to help study and save the sharks. Stream SHARK WEEK now on discovery+.

Meet the Deep Sea Sharks that Glow in the Dark

The largest bioluminescent creature on land or sea was found in the ocean near New Zealand.

Orcas Earn Their Killer Nickname in Brutal Attacks on Sharks

Six sharks washed up on a beach a few hours away from Cape Town, South Africa. As reported to Newsweek, these great white sharks were found dead, but the remains were meticulously torn apart. So what happened?

Two Orcas Are Hunting Great White Sharks in South Africa

A killer whale duo has been killing great white sharks off the Gansbaai coast, causing them to flee the area. These orcas have developed a taste for shark livers, transforming the local marine ecosystem.

Do Dolphins Have a New Skin Care Routine?

A new study on Indo-Pacific bottle-nosed dolphins reveals that pods might rub themselves on coral as a way to keep their skin healthy.

This Mighty Fish Loses 20 Teeth Everyday, Then It Grows Them All Back

That’s the equivalent of a human losing and growing back a tooth every day.

Underwater Noise Pollution Strikes the Wrong Chord

Meet Morgan J. Martin, PhD, a marine scientist who studies underwater sounds with whales, dolphins, and porpoises. Morgan observes how these marine creatures – also known as cetaceans – many of which navigate their underwater habitats through echolocation.

Related To: