Facts about Sharks
- Archeological evidence indicates that sharks have been around for more than 400 million years.
- Sharks are known as apex predators, meaning they are at the top of the food chain with no known marine predators.
- There are more than 500 species of sharks around the world that come in varying sizes, ranging from six inches to 39 feet long.
- Sharks have remarkable hunting adaptations that vary amongst other species. The Portuguese Dogfish shark hunts in total darkness up to a depth of over two miles, while the Blue shark will travel up to 5,700 miles to hunt.
- Sharks do not sleep in a state of unconsciousness. Rather, sharks will “sleep swim” in short intervals to continue taking in oxygen while resting.
- Humans are now the greatest threat to the survival of all shark species. 90% of the Pacific reef sharks have declined; 75% of the shark species in the Northwest Atlantic have been lost; and the Oceanic Whitetip has declined by 99%.
- Between 2000 and 2010, an average of 100 million sharks were killed each year. To put this number in perspective, this graphic shows how many sharks are killed by humans every hour compared to how many humans are killed by sharks every year.
Why We Need to Protect Sharks
- Role in the Ecosystem: As an apex predator, sharks help to maintain the balance of marine populations and keep the marine food web in check. Without sharks, mid-level species would overconsume species at the bottom of the food chain, causing entire ecosystems to collapse.
- Ecosystem Services: Stable populations of sharks help sustain fish stock populations. One study found that the collapse of the shellfish industry in the U.S. occurred because sharks were hunted to near extinction, causing an ecosystem chain reaction.
- Economic Contribution: Shark tourism generates $314 million annually and is projected to reach $780 million annually in the next 20 years. Shark tourism in the Bahamas generates far more revenue than direct hunting, helping both the local economy and the preservation of the shark species.
- Uniqueness: Sharks play a popular role in film, books, and TV, with shows like Shark Week. These sources provide a way to share knowledge about the uniqueness of sharks and the vital role they play in the marine environment. For a visual look at the unique beauty of sharks, check out this video from BBC Earth, which captures various shark species gathering in Costa Rica during their annual breeding journey.
Threats to Sharks
- Hunting and Finning: Nearly 73 million sharks are traded each year, primarily for their meat and fins. In the Galapagos islands, 90% of the 40 species found there are threatened by fishing outside protected Ecuadorian waters.
- Climate Change: As ocean temperatures rise and ocean acidification intensifies, the impacts of climate change will harm the well-being of sharks in several ways. Sharks will migrate further from their natural habitats, which may impact the availability and abundance of food resources and affect their ability to successfully produce offspring.
- Habitat Loss: Habitat loss is linked to the effects of climate change, as both rising sea temperatures and ocean acidification degrade shark habitats and increase the challenges for their survival.
- Bycatch: Sharks are susceptible to a certain type of bycatch known as trawling. When boats undertake trawling, large, tightly-woven mesh nets are dragged across the bottom of the seabed, which often destroys everything in the net’s pathway. A large number of sharks have been caught in these nets, resulting in mortality and severe damage to marine ecosystems.
What You Can Do to Help Protect Sharks
- Urge Congress to pass the Shark Fin Sales Elimination Act of 2019: This bill bans the buying and selling of shark fins in the United States. Take Action!
- Refuse shark products. Nearly 73 million shark fins are used in shark fin soup every year, fueled by a large demand in Asia. By refusing shark products, you can help lower the demand and drive down illegal hunting. While many countries have enacted full or partial bans on the practice of shark finning—cutting the fins from sharks while they are alive and tossing their bodies back into the ocean—many others do not have laws in place and illegal trade continues decimating shark populations around the world.
- Make safe and sustainable seafood choices. Some species of fish have healthy populations while others are in serious decline from overfishing. Bycatch—the catch of nontarget fish and ocean wildlife— contributes to overfishing and threatens marine species. Some sharks are overfished due to bycatch. Buy sustainable seafood and fish from fisheries and fish farms that support coastal communities and healthy marine ecosystems. To get started, check out a list of organizations that offer sustainable seafood resources across the world.
- Test your knowledge about threats to ocean ecosystems with our Oceans Plastic Pollution Quiz.
- Take personal steps to end plastic pollution.