Shark Background | Office of National Marine Sanctuaries

Sharks, a species that has existed for more than 400 million years, exist throughout our world’s ocean with more than 450 species of shark in total. Most sharks are apex predators and sit at the top of the food chain. They play a vital role in keeping the ecosystem healthy by feeding on animals that are lower in the food chain.

Sharks In Your National Marine Sanctuaries

Sharks have been around for a long, long time – they evolved before the dinosaurs did, and their time on Earth even predates trees! Over these hundreds of millions of years, they’ve adapted key features that enable them to thrive in a variety of habitats.

Three sharks swimming in a school of fish over a reef in dark blue water.

Sharks In Your National Marine Sanctuaries Photos

Sharks: mindless killers? Think again! Sharks are more than their scary reputation and play important roles in sanctuary habitats from coral reefs to the deep seas.

Great white shark swimming from right to left in dark blue water.

White Shark Natural History

Greater Farallones National Marine Sanctuary protects the wildlife and habitats of one of the most diverse and bountiful marine environments in the world. This area is one of the top four major upwelling areas in the world. These biologically and nutrient rich waters provide sustenance for major populations of top predators, including white sharks.

Tiger shark swimming up in dark blue water with its stomach in view.

Shark and Rays of Flower Garden Banks

Here's some guidance on how to interact appropriately with rays or sharks when you see them. Remember, sanctuary regulations prohibit you from touching, or harassing any rays or sharks.

Sixgill shark skimming the sandy bottom outside of a submarine window.

Sharks and Ecosystem Connectivity in the Channel Islands

Understanding which species and habitats exhibit high connectivity to the mainland is critical to proper management. It is well known that large pelagic species such as whales, sharks, dolphins, seabirds, and tuna are known to travel large distances between habitats, however many smaller species also move between the islands and mainland.

Light gray shark swimming from left to right.

Do Sharks Hunt People?

Most sharks are not dangerous to humans — people are not part of their natural diet. Only about a dozen of the more than 300 species of sharks have been involved in attacks on humans.

Greenland shark, gray and spotted, swimming in a dark ocean.

How Long do Greenland Sharks Live?

Scientists estimate the Greenland shark lives at least 250 years. They may live over 500 years. Scientists have suspected for a while that Greenland sharks lived extremely long lives, but they didn’t have a way to determine how long.

One researcher with a hat and orange vest, a researcher measuring a hooked shark underwater.

Shark Conservation

As one of the top ocean predators, sharks play an important role in the food web and help ensure balance in the ocean’s ecosystem. With increased demand and exploitation rates for some shark species and shark products, concern has steadily grown regarding the status of many shark stocks and their exploitation in global fisheries. NOAA Fisheries is committed to sustainable shark management.

Shark swimming to the left of a tall reef with a silver fish following behind.

Fish & Sharks

Fish are extremely diverse animals living in a variety of habitats ranging from coral reefs and kelp forests to rivers, streams, and the open ocean. Most fish can be categorized into one of two primary groups: bony fish (Osteichthyes) and cartilaginous fish (Chondrichthyes). The skeleton of bony fish is made of bones, while that of cartilaginous fish is made of cartilage. Cartilaginous fish include sharks, skates, and rays.