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How Do We Know Our Environmental Laws Are Working?

Ask a great white shark.
(Photo elevy/Flickr)

(Photo elevy/Flickr)

When it comes to sharks, conservationists are accustomed to bad news. Fisheries now kill around 100 million sharks every year—as bycatch, for their meat, and, most often, for their fins, a delicacy in many countries. No longer does society live in terror of sharks; instead, it fears for them. And for good reason: One-quarter of the world’s cartilaginous fish (that’s sharks, rays, and a few cousins) are at risk of extinction.

But in the case of America’s most iconic shark population—the great whites that congregate in the waters off Central California and occasionally venture under the Golden Gate Bridge—the picture looks a little different. California’s great whites aren’t telling us how we've screwed up the seas. They're telling us that our environmental laws are working.

We know that thanks largely to Chris Lowe, a marine biologist at California State University-Long Beach who 10 years ago noticed something strange. Even though fishing pressure had declined in recent decades, the remaining fishermen were accidentally catching more young great whites in their nets. Intrigued, Lowe and his colleagues implanted a number of year-old sharks—already the length of full-grown humans—with transmitters. The vast majority of the sharks, they discovered, survived the traumatic experience of capture.

"If all we sell is doom and gloom science, people are going to start asking why they’re being taxed for this stuff. We need to talk about how our environmental laws are succeeding."

In other words, the sharks seemed to be both plentiful and surprisingly hardy. "That got me thinking: Could this be real?" Lowe says. "We’re constantly being told that shark populations are overfished—but is it possible this population is actually increasing?"

Conventional wisdom held that the cartilaginous creatures were in decline. One 2011 study pegged Central California's population at just 219 adult and sub-adult sharks, an alarmingly low number. Conservation groups petitioned the state and federal government to list the species as endangered. But when Lowe went back and reviewed historical fishing records, his hunch grew stronger. Sharks were on the rise, he thought. And when he and colleagues re-crunched the data from the 2011 study using a model that took different account of the sharks’ migratory habits, his suspicions were confirmed. Rather than flatlining, great whites appeared to be thriving. This summer, Lowe and other scientists published a study estimating that more than 2,000 of the giant fish roam California’s coast.

What explains the uptick? Lowe believes that a suite of environmental laws conspired to save the great white. The Clean Water Act, passed in 1972, restricted discharges of industrial pollutants and sewage into coastal waters. The Marine Mammal Protection Act, also enacted in 1972, helped California sea lions—among the preferred prey of adult great whites—quadruple to around 300,000 animals today. Conservation-minded fisheries laws strengthened protections on species, like sea bass and halibut, that juvenile great whites depend on. And in 1994, California both proscribed the killing of great whites and banned gillnets, the type of fishing gear most often responsible for shark bycatch, from near-shore waters.

All told, by the mid-2000s, great whites were safer from slaughter than ever; their habitat was cleaner than it had been in decades; and their prey was growing more abundant by the day. “All of this legislation was put in place to bring things back,” Lowe says. “We’re starting to see signs of that.”

That success, to be sure, doesn’t mean we can declare the mission of recovering great whites accomplished. Ashley Blacow, Pacific policy and communications manager for the non-profit Oceana, points out that many young sharks won’t survive to adulthood. Around 200 juvenile great whites are killed each year far offshore, where gillnets are allowed. Although Oceana’s petitions to list the shark as endangered were rejected, the group still hopes to help develop solutions to bycatch, including reducing the amount of time gillnets can be left sitting in the ocean. “Some people say, oh, there are a lot of white shark pups being caught—that means there must be a lot of sharks out there,” Blacow says. “We say, there are a lot of pups being caught—we should do something about it.”

Moreover, just because the great white is bouncing back doesn’t mean that all sharks are so fortunate. This summer, scalloped hammerheads, whose populations had declined by some 90 percent, became the first shark ever to receive protection under the U.S. Endangered Species Act; overseas, a relative called the sawfish has gone extinct in 21 countries. And there’s no question great whites profit from fame and charisma that cryptic species like, say, the goblin shark can’t match.

While global shark concerns remain pressing, though, they don’t detract from this truth: State and federal environmental laws have bolstered great whites in California (and on the East Coast, too). To Lowe’s mind, those benefits aren’t touted often enough. “If all we sell is doom and gloom science, people are going to start asking why they’re being taxed for this stuff,” Lowe says. “We need to talk about how our environmental laws are succeeding.”

So the next time you’re glued to the Discovery Channel, and the serrated teeth and slate-gray flanks of Carcharodon carcharias flash on your screen, try to see the great white as neither killing machine nor victim, but as something else entirely: a barometer of regulatory success. Environmental rules like the Clean Water Act exist for a reason, and, contrary to what their opponents might tell you, that’s not to kill jobs or dampen the economy. That's because they work.