The myth and one that I love to debunk is that turtle eggs are aphrodisiacs. They certainly are NOT. People have analysed the nutrient content of turtle eggs and found them to be no better than chicken eggs. However, I do understand why coastal villagers claim them to be so. In the past when they very poor, under- and mal-nourished, they ate plenty of turtle eggs collected during the nesting season. Hence their nutrition status improved tremendously because of the added and much needed protein. This naturally gave them a sense of well-being and hence libido. In these modern days, they do not need to depend on turtle eggs any more as chicken eggs are readily available and much cheaper too.
In some South Pacific Islands, legends abound. In Fiji, there is this story about an ancient ancestor transforming herself into a turtle so that she could swim and fly through the water forever. In Satawal, Micronesia, the hawksbill was treated like a god and could not be caught or eaten (I like this one).
Famous local stories where turtles star: None so far.