> Green sea turtles have a relatively slow growth rate because of the low nutritional value of their diet. Body fat turns green because of the consumed vegetation.[61] This diet shift has an effect on the green turtle's skull morphology.[63] Their serrated jaw helps them chew algae and sea grasses.[64] Most adult sea turtles are strictly herbivorous.[61]

They might not be very efficient for farming for food without some breeding perhaps.

[0] https://en.wikipedia.org/wiki/Green_sea_turtle