Oceana | Protecting the World's Oceans

Blue sharks are one of the most wide-ranging and previously abundant shark species. Now, they are the most heavily fished shark in the world. An estimated 10-20 million individuals are killed by pelagic fisheries annually, mostly as bycatch.

The common thresher shark is easily identified by the unusually long upper lobe of its caudal tail. Such a lengthy fin allows the shark to herd and stun small schooling fish such as mackerels, bluefishes, needlefishes and lantern fishes.

Among one of the slowest growing sharks in the world, the dusky shark takes 20 years to reach maturity and has a 16 month gestation period. This low rate of increase makes dusky sharks particularly vulnerable to exploitation.

The lemon shark is found down to a depth of about 90 meters, but pups remain in shallow water for several years. They are known to withstand changes in salinity and can even be found in fresh water.

Young lemon sharks rely on protected coastal areas, which act as nurseries and are being degraded at an alarming rate. Lemon sharks are considered “Near Threatened” by the IUCN.

This bottom-dwelling, docile species is found in a variety of habitats which include continental shelves, corals and rocky reefs, mangroves and sand flats. Nurse sharks are equipped with long barbells on their snout to locate benthic prey.

This seasonally migratory species has a stocky body and short snout. Porbeagles are found around the world, but adjacent populations appear to be distinct. This species prefers colder waters and is, in fact, endothermic.

Sandtiger sharks are also known as the grey nurse shark and the spotted ragged-tooth shark. Sandtiger sharks have one of the lowest reproductive rates of any shark, giving birth to only one or two young every couple of years. Once a population is depleted, recovery is especially challenging due to their life history. Smaller populations are also much more susceptible to disease.

Possibly the fastest shark and certainly one of the most active, the shortfin mako is only found in tropical and warm temperate seas. During summer months, shortfin makos follow patches of warm water.

The spiny dogfish, also known as the spurdog, is found within all of the world’s oceans. Spiny dogfish are caught for a variety of purposes which include: fish and chips, shark fin soup, fertilizers, liver oil, pet food and as a popular dissection specimen in academic science labs.