Swimming beneath a school of scalloped hammerhead sharks is a dream for many divers. But for those diving the sea mounts along the tip of Baja, California, that dream has been out of reach for over a decade. The sharks (Sphyrna lewini) once moved through these waters in monumental numbers, but overfishing has seen them all but disappear in recent years. So when wildlife filmmaker Adam Ravetch heard rumour of a hammerhead gathering in the area, he had to check it out.

"At least in the last [decade], no one has seen many hammerheads here," he says. "But some of the old fisherman were saying they're still there. So I decided to go down and see if I could find them."

After days of diving with no sharks in sight, Ravetch started to lose hope ... but a strong current prompted him to try one more time. He recalls: "So we're waiting – about 30 minutes into it – and still, nothing was happening. And then, in the distance I see hammerheads ... not just one, but 40! This hadn't happened in [so long], and now we've got a shot that shows they may be coming back."

Scalloped hammerheads are among the most threatened of all long-distance swimmers, and have recently become the first species of shark protected by the US Endangerd Species Act. They've got a long way to go, but Revetch is hopeful that what he witnessed in California is the beginning of a turnaround for these sharks – the result of decades-long work by marine biologists, conservationists and policymakers to curb overfishing. "Without the overfishing, if hammerheads are starting to return, it will represent a change in the environment for Baja, California. It's still wild, it's still rich with possibility ... there's hope," Ravetch says.

Dr Christopher Lowe, director of the California State University Long Beach (CSULB) Shark Lab is also hopeful that this might be the case, though he does caution that the hammerhead sightings could be attributed to this year's El Niño-like conditions. "We had quite a few sightings of smooth hammerheads in southern California waters this summer, which are common during El Niño years."

But there is reason to be optimistic, he adds."It's possible that we're seeing some signs of population recovery due to fisheries restrictions. Mexico has been doing a little better in terms of shark fishing regulations."

Top header image: BlueRidgeKitties/Flickr

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