To many scuba-certified cruise passengers, one of the best parts of the voyage is the chance to explore beneath the waves they’ve been crossing. And according to a national survey released today by the environmental advocacy group Oceana, there’s a strong economic incentive to keep that endangered underwater world as healthy as possible.

Oceana’s study found that the USA’s 1.2 million active scuba divers contribute more than $4.1 million dollars to local coastal economies each year, spending an average of $2,424 per trip. What’s more, they’ll cough up extra cash for a better chance of communing with sea turtles and sharks in a sound coral reef environment.

More than 95% of surveyed divers said they’d be willing to donate an entrance fee to dive in a protected healthy coral reef ecosystem. Another 76% would pay more for an increased likelihood of swimming with a sea turtle in the wild, with an average additional amount of $29.63.

And cue the theme music to Jaws: Sharks are clearly worth more alive as part of the ecotourism industry than dead as part of the fishing industry. Seventy-one percent of divers said they’d pay more to see sharks, an average of $35.36 per dive.