From Seeturtles.org in the USA:
Cuba Sea Turtle Volunteer Expedition
Spend a week volunteering with a sea turtle conservation project in the incredible Guanahacabibes National Park, along Cuba’s western coast. Work side by side with Cuban biologists to study and protect nests of green and loggerhead sea turtles. During the day, explore the park’s forests, reefs, and caves. This trip is a partnership between Cuba Marine Research & Conservation Program, Altruvistas, and SEE Turtles. Profits from this trip will help to save at least 500 hatchlings at this turtle nesting beach per participant.
2016 Dates: July 16 – 23 (full) / July 30 – Aug 6 (open)
Price: $2,995 per person (includes airfare from Miami – Havana; price without airfare is $2,395). Havana extension: $550 pp. Single supplement: $320.
Roundtrip airfare from Miami to Havana ($600 value), guide, private transportation, accommodations, most meals, activities, and a donation to turtle conservation.
Excludes: Airfare to Miami, personal items, and tips for the guide/driver.
This trip is open to American citizens through a “People to People” license given by the US State Department to our partners. It’s also open to citizens of other countries.
Minimum recommended age is 14 years old, under 18 needs to be accompanied by an adult.
Group size is limited to 16 people maximum.
Discount of $50 per person for paying by check.
Payment plans can be arranged.
Environmentalists fear Americans will ruin Cuba’s biodiversity: here.