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What Are the Three Most Common Sharks of the World?

Marine biologists studying the numbers and population counts of shark species around the world rely largely on educated guesswork based on prior year data, sightings, tagging and fishing reports to verify their estimates of shark populations (especially for sharks in the open ocean). As a result, determining exactly which species of sharks are the most numerous is a difficult process, and there are a number of contenders for the list. Nevertheless, some species of modern sharks are known to be extremely prevalent.

Spiny Dogfish Shark
- Discovery Channel's website says that spiny dogfish are perhaps the most abundant sharks in the world. The Marine Biodiversity website of the Canadian Shark Research Laboratory describes the spiny dogfish as "a small schooling shark that forms groups of hundreds or thousands of individuals of the same size." Additionally, this shark appears off the coasts of the oceans in all temperate waters. Seaworld's website says that fisherman catch more than 27 million spiny dogfish sharks a year in the coastal waters of Massachusetts.
The Blue Shark
- The aptly named blue shark possesses, according to the Marine Biodiversity website, a deep indigo blue coloring along its top side and a vibrant blue on its sides. It ranges across the Atlantic, Pacific and Indian oceans. It can be found from northern waters off the coast of Norway to as far south as the Straits of Magellan. Because of this enormous range, the Canadian Shark Research Laboratory believes that the blue shark "is likely the most prolific of the large shark species as it is abundant throughout its range."
The Sandbar Shark
- According to the Aquarium of the Pacific's website, the sandbar shark is the most common species of shark along the U.S. Atlantic Coast. A large shark like the blue shark, the sandbar shark swims along the bottom of the coastal waters and is, according to the Florida Museum of National History, rarely seen at the water's surface. It eats small coastal sea life like fish, crabs and shrimp.
Shark Conservation
- One reason why firm population counts and figures are few and far between for sharks (and other forms of marine life) is that humans have overfished the oceans and decimated the populations of many species. Sharks are not only sought after by individual anglers for the challenge involved but are also overfished commercially throughout the world. Many shark species are considered either endangered or threatened by human fishing activities, and according to a SharkSafe, a shark conservation website, some species may have declined by up to 99 percent since the late 20th century. If the trend of overfishing sharks is not reversed, many species may never recover.

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