Wow the weather broke and were diving with Turtles on every dive. Its the time of the year the big guys come back to where they where born to mate.
The females will be nesting shortly after.
heres some good info on whats going on.
Courtship & MatingCourtship and mating for most sea turtles are believed to occur during a limited "receptive" period prior to the female's first nesting emergence. Afterwards, only females come ashore to nest; males almost never return to land once they leave the sand of their natal beach. During mating season, males may court a female by nuzzling her head or by gently biting the back of her neck and rear flippers. If the female does not flee, the male attaches himself to the back of the female's shell by gripping her top shell with claws in his front flippers. He then folds his long tail under her shell to copulate.
Females observed on the nesting beach after recently mating often have scratched shells and may be bleeding from where the males' were hooked to their shells. Copulation can take place either on the surface or under water. Sometimes several males will compete for females and may even fight each other. Observers of sea turtle mating have reported very aggressive behavior by both the males and females. Females may mate with several males just prior to nesting season and store the sperm for several months. When she finally lays her eggs, they will have been fertilized by a variety of males. This behavior may help keep genetic diversity high in the population.
MORE http://www.cccturtle.org/seaturtleinformation.php?page=behavior