Safe haven for hammerheads in Galapagos Islands
For millions of years, new-born hammerhead sharks have grown up in nurseries sheltered by the mangrove swamps and reefs of the Galapagos Islands, safe from all human threat. But until November, biologists had no idea the sharks had their own hideaway that could hold the key to secrets of this remote archipelago 1,000 kilometers off South America’s Pacific coast.
“It was quite by chance that we found this natural nursery for baby hammerheads, a species that is under a high level of threat,” said Eduardo Espinoza, the biologist in charge of monitoring ecosystems in the Galapagos Marine Reserve. “It is a unique area, of great interest to conservationists.”
Still stunned by the find, Espinoza and his team are returning by boat to the spot in northeastern Santa Cruz to collect data and attach tracking devices to the young sharks.
Clearly visible in the water, dozens of small, silver-skinned sharks, one eye on either extremity of their T-shaped heads, glide gently among other species of fish, looking for the crustaceans they feed on during their early years.
“The females arrive to give birth and then leave. The young ones have all the food they need here and the reefs afford protection from large predators,” said Espinoza as he cast a wide net into the water.
They can grow as long as 3 meters and live to 50 years.
The park rangers have been monitoring and tagging sharks for years, one of the landmark species of the 138,000-square-kilometer marine reserve, the second-largest oceanic park in the world, which has been named a Natural Heritage Site.
But the discovery of these sharks has been a particularly sensitive issue, as overfishing and the illegal capture of sharks has placed them on an endangered species list, two levels below extinction, says the International Union for the Conservation of Nature.
Their slow physical development and low reproduction rates have only exacerbated the threat. That makes attaching tracking devices all the more delicate.
“Shark, there to the right!” shouts one of the team members.
The captain moves the boat closer to the net as one of the assistants grabs the half a meter long shark and holds it on a table so it can be measured and weighed, have its sex determined and insert a tracking chip to log its habits and migration routes.
Putting the young shark back in the water, they move its head and tail to revive it, until it swims off on its own.
“They cannot spend more than 2 minutes out of water as they need a constant flow to avoid dying. It’s like a pit stop in Formula 1 racing,” said the biologist.