Whale sharks feed upwards of 8 hours per day, filtering thousands and thousands of gallons of surface water. We are advocates of protecting animals in the ocean and would like to see everyone wearing protective clothing rather than sunscreens. If absolutely necessary, the only sunscreen we recommend for people to use is a bio degradeable, reef safe sunscreen and to apply it sparingly before you leave the Cancun Marina and after the snorkeling tour on the Isla Mujeres Reefs. The boat is covered with plenty of shaded areas. The use of sun protection clothing is still the best option when being out in the sun, hat, long sleeve shirt rashguard to save the whale sharks and the other reef inhabitants. We thank you for your help and understanding!