Threats to Sharks

Although the risk of being bitten by a shark is incredibly small, people often think of sharks as being a significant threat to personal safety. From 2004-2013, the total number of people bitten by sharks worldwide ranged from 53 to 81 per year (source: International Shark Attack File). Of those, the number of fatal bites ranged from one to 13. When you consider the millions of people who are in the water every year, these are very small numbers. However, if you are one of those bitten, or a friend or relative of someone killed by a shark, there is little comfort in knowing how small the risk is.

But in comparing all interactions between people and sharks, who is really more deadly? A 2012 study (Worm, B. et al, Global catches, exploitation rates, and rebuilding options for sharks, Marine Policy 40 (2013) 194-204) estimated that 100 million sharks were killed in 2000, 97 million in 2010, and the range of possible values was between 63 and 273 million sharks killed per year.

Why are so many sharks being killed? Mostly for their fins. There is a huge demand for shark fins, for use in shark fin soup and traditional medicine, especially in China and its territories. The fins are often harvested selectively. Fishers catch a shark, cut off its fins, then discard the rest of the shark, often still living, back into the ocean. Without its fins, the shark can’t swim, and soon dies.

Most shark species, including those sought by commercial fisheries, are slow to mature, produce relatively small litters, and may not reproduce until 8 to 20 years of age. Most female sharks do not develop new eggs until after giving birth, and may not breed again for a couple of years. Compare this with most bony fish species, which spawn hundreds or thousands of eggs at a time, year after year.

Sharks are therefore quite vulnerable to overfishing, being removed from the ocean faster than they can reproduce. In addition to being harvested for their fins, sharks are often taken as by-catch in other commercial fisheries, and some are popular targets for recreational fishing. As a result, shark populations around the world have been in decline for decades, with some species dropping in numbers by up to 80% over the last 50 years.

As of 2013, shark finning had been banned by 27 countries and the European Union. In Canada, shark finning has been illegal since 1994. President Clinton signed the Shark Finning Prohibition Act of 2000, banning shark finning on any vessel within United States territorial waters, and on all U.S.-flagged vessels in international waters. In 2010, Hawaii became the first state to ban possession, sale, trade, and distribution of shark fins.

However, shark finning continues in international waters, especially most of the Pacific and the Indian Ocean.

So who’s more deadly, man or shark?