The Green Sea Turtle
The green turtle (Chelonia mydas) is not actually green in color, but mottled brown. The name is derived from the greenish fat of the body. The carapace (the upper portion of the shell) is light or dark brown. It typically has radiating mottled or wavy dark markings or large dark brown blotches. The green turtle is considered large in size for sea turtles with an average length of 36-48 inches (90-122 cm). The record was set at 60 3/8 inches (153 cm). Its weight ranges from 250-450 lbs. (113-204 kg) with the record at more than 650 lbs. (295 kg). The upper surfaces of young green turtles are dark brown, while the undersides are white. The ends of the flippers are black, but are edged with white. There is a keel running down the center of the back and a pair of keels down the plastron (lower portion of the shell). Hatchlings are 1 5/8 to 2 3/8 inches in length and are black above, but become much paler by six months. The green turtle is primarily a tropical herbivorous species and feeds on sea grasses and algae. Under the Endangered Species Act it is considered “endangered” for the breeding populations in Florida and the east Pacific and “threatened” everywhere else.
The main reason for the decline of the green turtle was its culinary appeal. Recipes for green turtle were very popular in the past, with two of the most famous being “calipash” and “calipee”, which are soups made from the upper and lower shells. Green turtle recipes were also popular overseas with England and Cuba being major importers. The green turtle was first introduced into England as a luxury food in the 18th century. They were in such demand by 1879 that approximately 15,000 were being shipped there annually. Green turtles became an important food source for the British Royal Navy and were taken on as living provisions at specially scheduled stops. During this time, the green turtle was known as the Texas turtle, because of the fishery that existed for it in the Corpus Christi area and other areas of Texas until the 1890’s. The demise of the fishery and the precipitous decline of this species are thought to have been due to over-exploitation and freezing temperatures. In the Gulf of Mexico, green turtle fisheries also existed at Cedar Key in western Florida, the Florida Keys, and the Dry Tortugas.
Today, south Texas inshore waters provide very important habitat for green sea turtles. Padre Island National Seashore has conducted extensive research on green turtles in Texas, including individuals found stranded in Texas, netted at the Mansfield Channel, and satellite tracked after capture at the Mansfield Channel. Most green turtles in Texas waters are juveniles and their numbers are increasing. Although they are still impacted by several mortality factors, their most significant threat in Texas is hypothermic stunning. However, if hypothermic stunning victims are found alive and taken to rehabilitation facilities, many of them survive and are later released.
The major nesting areas for green turtles in the Atlantic are in Florida, Mexico, Surinam, Guyana, French Guyana, Costa Rica, the Leeward Islands, and Ascension Island in the mid-Atlantic. Padre Island National Seashore and South Padre Island are the only locations on the Texas coast where green turtle nesting has been documented. The majority of Texas records have been from the National Seashore. The first confirmed green turtle nest recorded on the Texas coast was at Padre Island National Seashore in 1987. However, they may have nested here before their decline. For years the National Seashore was a private grazing area and a bombing range, receiving limited visitation, and historically visitors were not asked to report nesting. During recent years, from 1-5 green turtle nests have been confirmed on the Texas coast each year and nesting has been relatively stable. Nesting has been documented on the Texas coast between June and mid-September. Some nests may go undetected since most nest detection efforts end in mid-July and green turtles may nest through mid-September. Due to the rarity of green turtle nests and the very active state and unpredictability of the hatchlings, releases of green turtle hatchlings are rarely open to the public at the National Seashore.