No Smooth Sailing for the Smooth Hammerhead

The smooth hammerhead shark (Sphyrna zygaena) gets its name from its large, hammer-shaped head. While it may look like a cartoon character, this shark can grow up to 16 feet long and weigh almost 900 pounds! The smooth hammerhead is a coastal-pelagic, semi-oceanic shark – meaning it prefers warmer, shallow waters. Unfortunately, those waters are also frequented by recreational and commercial fishermen, putting the smooth hammerhead at great risk. This shark is considered vulnerable worldwide and populations off both U.S. coasts have plummeted by 91% in the Northwest Atlantic. Even worse, the species is near total extinction in the Eastern Pacific

The Problems

Commercial fishing is the main threat to the smooth hammerhead: sharks are either targeted deliberately or caught accidentally as bycatch. Smooth hammerhead fins are some of the most valuable fins in the international shark fin trade. As a result, the reported catch of smooth hammerheads has increased in every region over the last 10 years. Even when the smooth hammerhead is caught accidentally and released, more often than not, the animal dies anyway. This species is extremely sensitive to handling, and as many as 90% of smooth hammerheads die even when they are released.

The smooth hammerhead is also targeted by sport hunters. The United States is home to one of the largest recreational shark fisheries in the world, and because there are still few fishing restrictions on most hammerhead species, these sharks are a popular catch. In 2012, Florida boats alone reported a yearly total catch of 33,000 hammerheads.

Several factors make the smooth hammerhead especially vulnerable to extinction. To begin with, the large size of the smooth hammerhead means that there are fewer individuals. Because sharks are so large, it takes fewer of them to reach the maximum number of these apex predators that their habitats and ecosystems can sustain. This means each individual animal is more important to the species’ survival than those in a smaller, more numerous species. Moreover, the shark’s slow rate of reproduction makes it difficult for the population to recover quickly when its numbers have been severely reduced. So even though the global shark fin trade is now thought to be on the decline, the effects of severe overfishing on the smooth hammerhead population are both devastating and long-lasting.

Smooth Hammerhead Shark, © Andy Murch/Elasmodiver.com

There’s another factor that puts the smooth hammerhead at risk— it looks a lot like the scalloped hammerhead. That shark, which faces many of the same serious threats, was so heavily targeted by fishermen that it became the first shark species to be offered protection under the Endangered Species Act (ESA) just last year. Yet its fate remains intertwined with the smooth hammerhead. The two species are so similar in appearance that they are difficult to tell apart, even when landed whole. When their fins are removed, it is almost impossible. Because it’s so easy to confuse the two, leaving the smooth hammerhead unprotected makes it harder to enforce legal protections for the scalloped hammerhead as well.

The Solutions

In 2013, the smooth hammerhead was listed under the Convention on International Trade in Endangered Species (CITES), the largest international agreement regulating trade in wildlife. However, protection under CITES only regulates the international trade of the species through a permitting system; it does not ban trade completely. Furthermore, CITES does not address population threats that are unrelated to trade, such as recreational fishing and bycatch. On the other hand, a listing under the ESA would keep the shark from being directly targeted by fishermen—commercially or recreationally—in U.S. waters. It would also prohibit shipments of smooth hammerhead products through the United States, and pave the way for additional protections in the future.

Because of the continued threats to this vitally important species, Defenders is filing a petition asking the National Marine Fisheries Service to protect the smooth hammerhead under the ESA. This shark is in desperate need of additional protection if it is to recover from severe population declines worldwide. We are eager to see the smooth hammerhead benefit from the same legal protections given to the scalloped hammerhead last year.