Cuba on Wednesday launched an initiative to protect sharks in some of the most pristine habitat for the predators whose populations have been in steep decline.

The action plan, reached through two years of collaborative research with the New York-based Environmental Defense Fund (EDF), will impose size and capture limits on fishermen, set aside protected areas and create closed seasons for shark-fishing, officials said.

The Cuban government has recognized its special place in the world of sharks as scientists believe nearly 100 of the world's 500 shark species swim in Cuban waters, sustained by a relatively healthy coral reefs, the EDF says.

Protecting shark populations also makes business sense for the fishing and tourism industries. Scuba divers travel from around the world to swim with Cuba's sharks.

"Cuba is considered the crown jewel of the Caribbean, principally because of its incredible coral reef ecosystems, its mangroves, its sea grasses," said Daniel Whittle, EDF's Cuba program director. "Healthy sharks mean healthy corals. Healthy corals mean healthy sharks."

Cubans fish sharks for their meat, and more aggressive overfishing and environmental degradation elsewhere in the Caribbean have taken their toll, which is why conservation needs to be international, Whittle said.

The EDF last year put an electronic tag on one longfin mako shark off Cuba that swam some 6,000 miles (10,000 km) over five months, reaching the coast of New Jersey, Whittle said.

Cuba already has protective measures such as banning "finning," the harvesting of sharks only for their fins.

The new action plan "will empower scientists in Cuba ... who will work directly with fishermen. That information will be used by managers to develop new closed areas that sharks need for nurseries, management measures to protect juveniles, rebuild populations and help sustain them," Whittle said.

The plan builds on research developed by Cuban scientists who have been working with fishermen for the past five years to understand which species are most vulnerable.

"Getting fishermen involved in collecting data has been critical," Jorge Angulo, senior scientist with Cuba's Center for Marine Research, said in an EDF statement.

Photo: Silky Shark off Cuba by Alex Chernikh