Secret Seahorses

In the Bahamas, one mysterious, landlocked pool is home to a little-known population of seahorses taking its own evolutionary route.

- Helen Scales

On one of the islands of the Bahamas, in the Caribbean Sea, there’s a large, landlocked pool that holds some remarkable secrets. For a long time, local islanders have told stories of monsters that live there, a giant octopus and turtle, and fish that sing. But within the pool’s shadowy waters lives a collection of real animals far more fantastical than any imagined beasts. Hiding in seaweed gardens are hordes of crabs, brittlestars and octopuses (normal-sized ones). Most incredible of all, the pool is home to the world’s largest known population of seahorses.

Masters of camouflage

“At first you may not think there’s anything in there,” says Shane Gross, an underwater photographer who has visited the pool 40 or 50 times. With their heads hunched down and colours matching their surroundings, the seahorses look a lot like clams or mussels. When he brings friends to snorkel in the pool, they can spend half an hour searching in vain for seahorses. As soon as he points one out and they know what to look for, they realise there are seahorses everywhere. “They’ll spot one every minute or two after that,” he says. Nowhere else in the world will you have a better chance of spotting one of these curious little fish.

Seahorse biologist Heather Masonjones, of the University of Tampa in Florida, has been studying the pool for the last five years. Before that, she mainly focused on seahorses in the Gulf of Mexico and right on her doorstep in Tampa Bay. Then she got a tip-off from staff at the Bahamas National Trust about a little-surveyed pool on one of the archipelago’s islands that they thought might be home to seahorses. Heather had no idea that she would find so many there. “It’s just remarkable,” she says.