LA RESTINGA, Spain (Reuters) - El Hierro's crystal-clear waters and abundance of marine life have made this island in Spain's Canaries archipelago one of the world's top scuba diving spots.
But this year, the arrival of nearly 12,000 migrants on dugout wooden boats, or cayucos, from Africa means it is becoming better known as a new gateway to Europe.
At the tiny port of La Restinga, dive boats pick their way between around 20 abandoned cayucos in which discarded clothes, plastic utensils and petrol cans are still visible.
At least four have sunk in the harbour, disgorging rubbish and fuel into waters that are part of a marine reserve.
The delay in removing the boats from the water amid a record surge in migrant arrivals has locals worried about its impact on tourism, the island's main source of income.
Local politicians, fishermen and tour operators are calling for more help from Spain's government and the European Union as islanders do what they can to help migrants who land wet, exhausted and often dehydrated or with hypothermia.
"If this boat, which has been here for more than 30 days, sinks, all the petrol, the oil from the engines, what's inside, will go to the bottom, in a national marine reserve," said Fernando Gutierrez, the head of the port's fishermen's union.
The cayucos occupy a third of La Restinga's marina, from where eight dive operators depart at least twice a day with dozens of dive groups.
Tourists from Germany, Switzerland and mainland Spain said they were saddened by the situation as they watched Red Cross officials and local doctors attend to newly-arrived migrants sitting wrapped in thermal blankets on the dock awaiting registration.
Many migrants die en route and at least six died after arriving at the island in the last two months alone.
Alpidio Armas, president of El Hierro's local government, said neither Spanish authorities nor the EU had grasped the magnitude of the crisis.
Genevieve Gosses, 55, a diver from France, said some friends had cancelled plans to visit El Hierro because of the crisis.
In recent weeks, divers practising in the harbour have found clothes and even passports on its bottom, said Ginela Horn, director of a local dive company.
"We haven't had any bookings cancelled yet but our clients are asking a lot of questions about the situation, whether it will get worse... it's a bit complicated to provide an answer," Horn said.
(Reporting by Corina Pons, Horaci Garcia and Borja Suarez; editing by Charlie Devereux, Alexandra Hudson)