Why Sharks Matter for a Healthy Ocean

Gliding through the water with an iconic dorsal fin and a powerful flick of a tail, sharks are graceful, elegant, and a key part of the ocean ecosystem.

“Sharks are beautiful animals, and if you’re lucky enough to see lots of them, that means that you’re in a healthy ocean. You should be afraid if you are in the ocean and don’t see sharks.” – Dr. Sylvia Earle, Founder & CEO, Mission Blue

Sharks have been swimming through the ocean for over 400 million years—long before trees, flowers, or dinosaurs—and today more than 500 species can be found around the globe. They come in all shapes, sizes, and colors, from speckled whale sharks, the largest species, to the pink goblin shark, the flattened angel shark, and the dwarf lanternshark, one of the smallest known species, which grows to only about 8 in (20 cm).

Grey nurse shark in the Byron Bay Hope Spot. © Francois Burger

Raggies in a cave in the Aliwal Shoal Hope Spot. © Dr. Ryan Daly

Sharks, big and small, help keep the ocean healthy. As predators, many sharks help maintain balance in underwater ecosystems by influencing the behavior and abundance of other animals. Their presence shapes food webs, supports biodiversity, and protects habitats. They help kelp forests thrive by managing sea urchin populations, and act like sheepdogs in seagrass meadows, their presence encouraging grazing animals like dugongs to move around, preventing overgrazing and allowing new growth.

Great white shark in seagrass, South Australia. © Jayne Jenkins / Ocean Image Bank

But sharks are facing another threat: humans.

Worldwide, overfishing is the greatest threat sharks face. Some are targeted for their meat, fins, liver oil, and gill plates. Others are accidentally caught as bycatch in fisheries aiming for other species. A 2024 global status report from the International Union for Conservation of Nature (IUCN) found that over 300 species of sharks, rays, and chimaera fish are threatened with extinction. Many shark species grow slowly, mature late, and produce only a few babies, so their populations can take a long time to recover once they’ve become depleted.

Sharks also face increased pressure from habitat loss and degradation, pollution, and climate change. Warming ocean temperatures and stronger storms affect where sharks and their prey live, while coastal development damages important nursery areas where young sharks shelter, such as mangroves.

In some coastal regions around the world, shark nets and drumlines add another threat.

Shark nets and drumlines are most closely associated with South Africa and Australia, but similar shark-control measures have also been used or trialled elsewhere, including Brazil, Réunion Island, and, historically, Hawaii. In parts of South Africa and Australia, these methods have long been used near popular beaches with the goal of reducing the risk of human-shark encounters. But they do not create a true barrier between people and sharks. Shark nets are designed to entangle large marine animals, while drumlines work like baited fishing hooks, catching sharks and other wildlife that come near them.

Their impacts are especially visible across globally significant marine areas, including Mission Blue Hope Spots in South Africa and Australia. At Aliwal Shoal in South Africa and along the Sydney Coast, the Great Barrier Reef, Byron, Gold Coast, and Moreton Bay Hope Spots in Australia, communities, scientists, and Hope Spot Champions have seen how shark nets and/or drumlines can harm coastal ecosystems. Recent Australian data show that 89% of animals caught in shark nets during the 2024/2025 season were not target sharks but rather dolphins, leatherback turtles, and endangered gray nurse sharks, among others. More than 67% of the animals caught died during capture or after release.

There are better ways forward. Alternatives, including artificial reefs and magnets, aim to drive sharks away from coastal waters without capturing them. Many coastal communities are moving away from lethal shark-control programmes and toward non-lethal tools such as drones, shark-spotting programmes, real-time alerts, eco-barriers, and SMART drumlines — approaches that can help protect people without unnecessarily harming sharks and other marine life.

Local communities and local governments can make a difference by working together, hosting educational events to build awareness and encouraging implementation of alternative technologies. Through collaboration, community engagement, and advocacy, shark nets can be a thing of the past.

Sharks aren’t villains. They’re ancient, remarkable creatures and vital allies in the fight for a healthy ocean.

What can you do?

• Support local and national policies that replace lethal shark nets and drumlines with science-based, non-lethal safety measures.
• Advocate for stronger protection of Important Shark and Ray Areas, especially fully protected no-take zones where sharks and rays can recover from fishing pressure.
• Choose sustainable seafood and ask questions about how it was caught.
• Learn about and share accurate shark science to help replace fear with understanding.

A healthy ocean needs sharks. And sharks need us to act. Click here to see more photos of sharks in our Hope Spots!

Juvenile scalloped hammerhead in the Gold Coast Hope Spot. © Dr. Olaf

Leopard sharks in the Great Barrier Reef Hope Spot. © Angel Grimaldi

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Mission Blue Hope Spots who are working on shark protection around the world:

To support shark protection in South Africa, visit Wild Alliance Africa, led by Aliwal Shoal Hope Spot Champion Russel Symcox, or follow the Aliwal Shoal Hope Spot Facebook page and learn how to get involved in local ocean conservation efforts.

In Australia, Ocean Lovers Festival champions the Sydney Coast Hope Spot and offers ways to take action for sharks at: https://www.oceanloversfestival.com/act

Across the Great Barrier Reef, Citizens of the Great Barrier Reef, led by Hope Spot Champion Andy Ridley, is mobilising citizen science and community action to help protect one of the planet’s most iconic marine ecosystems.

In Byron Bay, Hope Spot Champions Alice Forrest and Dr Elizabeth Hawkins at Ocean Education and Conservation are working to strengthen protection for the region’s rich marine life, from sharks and rays to dolphins, turtles, and whales.

On the Gold Coast, Hope Spot Champion Dr Olaf Meynecke of Humpbacks & High-rises is advancing science, education, and advocacy to support safer coexistence with marine wildlife.

In Moreton Bay, Hope Spot Champion Dr Chris Roelfsema with Reef Check Australia supports citizen science and community stewardship for one of Australia’s most biodiverse coastal ecosystems.

Across the Eastern Tropical Pacific, Hope Spot Champions Alex Hearn (Galápagos Islands), Sandra Bessudo (Malpelo Island), Randall Arauz (Cocos Island), Todd Steiner (Cocos-Galápagos Swimway), Héctor Guzmán (Coiba Ridge), and James Ketchum (Gulf of California), are advancing research on the movements of highly migratory shark species to reveal how these ocean travelers connect ecosystems across vast marine areas. Follow MigraMar’s work to learn how science is driving stronger protections across the region.

In Costa Rica, Misión Tiburón, led by Hope Spot Champions Ilena Zanella and Andrés López, is working to protect Golfo Dulce, a critical nursery area for scalloped hammerhead sharks.