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Sharks

SEE Sharks

Sharks are the ocean’s top predator; the health of the ocean depends on healthy populations. There are more than 1,100 species of sharks and rays around the world.

Did You Know?

Sharks, skates, and rays are collectively termed Elasmobranchs, a subclass of Chondrichthyes, or the cartilaginous fishes. They have a skeleton made entirely of cartilage rather than bone as in other fishes.

In general this group is slow growing, late maturing, and produce few young compared to other fishes. These characteristics make them especially vulnerable to exploitation by humans.  

Sharks have a streamlined body, 5 to 7 pairs of gill slits depending on the species, and skin covered in small scales called dermal denticles which make the skin feel rough and sandpaper-like. They do not have a swim bladder for buoyancy like other fish but have a large oil-filled liver.

They also possess a lateral line, a sensory organ comprised of a narrow line of sensory cells that runs the length of the body and into the head. Some pelagic (open ocean) species do not have spiracles and rely on actively swimming to move water over their gills in order to obtain oxygen from the surrounding water.

Skates and rays have pectoral fins that are enlarged to form “wings” that propel them through the water and have flattened bodies which help them to feed on the bottom. They are mainly bottom-dwelling with the exception of eagle and Manta rays. Worldwide there are more than 1,100 species of sharks, skates, and rays.

WHY ARE SHARKS ENDANGERED?

Sharks are endangered because of threats that are the result of human activities including shark finning and getting caught in fishing gear. These are apex predators (at the top of the food chain) and play an important role in the health of the oceans.

Without them, the entire food chain can be affected, negatively impacting the entire ecosystem. Sharks are long-lived, mature late, and produce few young making them especially vulnerable to exploitation.

Status of Feature Species

Commercial Fishing

The biggest threat to sharks, skates, and rays is the overfishing and over-consumption of their meat, fins, and cartilage. Shark fins are particularly sought after for traditional Chinese medicine and shark fin soup which is considered a delicacy in Asia.

Commercial shark-finning is a practice where sharks are caught and their fins are cut off, then the body of the shark is discarded. Shark finning kills an estimated 100 million or more sharks globally per year.

Bycatch

Bycatch in commercial fisheries is also a major threat. Bycatch is the unintentional capture of a non-target species. Fisheries targeting tuna and billfish in particular have a high impact on sharks.

Rays and skates are also under threat from unintentional capture in commercial fisheries. They are greatly impacted by bottom trawl fisheries as they are mainly bottom dwellers. Bottom dwelling sharks are also impacted by this fishery.

Habitat Degradation

Sharks depend on healthy ecosystems to survive and find prey. Habitat degradation includes effects from climate change, pollution, and destruction of areas like mangroves and reefs.

These areas are used by sharks for breeding and finding prey, and provide protected habitat for their young.  

SHARK CONSERVATION

Shark conservation organizations are working to confront the threats facing sharks and rays. Below, you will find links to organizations that protect sharks and links to news articles about shark conservation.

Shark Conservation Organizations:

Links & Articles

Sharks