Though sub-adults and adults common, number of green sea turtles living and foraging within Midway's lagoon is undetermined at this time. Many of Midway's turtles have been tagged, providing a useful tool for monitoring the population. Foraging grounds restricted to depths where sunlight, substrate and nutrients are conductive to plant growth, usually less than 10m deep and frequently not more than 3m deep. Foraged macro algae species in the Northwestern Hawaiian Islands include Caulerpa, Turbinaria, Spyridia, Codium, and Ulva . Breeding Adults migrate from foraging grounds throughout the Hawaiian Islands to breeding grounds.
Males appear to migrate every year, arriving ahead of the females.
Females only migrate every 2- 4 or more years. Copulation occurs in shallow waters near nesting beaches. Nesting activity has not been recorded on Midway Atoll. Nesting at FFS occurs from late April through September with a peak in June-July. Hatchlings emerge en-masse, usually at night, from a sandy 2 ft deep nest after about 60 days.