Green Sea Turtle (Chelonia mydas)

The green sea turtle was listed as endangered/threatened on July 28, 1978. The breeding populations off Florida and the = Pacific coast of Mexico are listed as endangered while all others are threatened.

Distribution

In the southeastern <= st1:country-region w:st=3D"on">United States, green turtles are found around the U.S. Virgin Islands, Puerto Rico, and the continental U.S. from Texas to Massachusetts. Important feeding groun= ds in Florida include = Indian River Lagoon, the Florida Keys, Florida Bay, Homosassa, Crystal River and Cedar Key. The primary nesting sites in U.S. Atlantic waters are along = the east coast of Florida, with additional sites in the U.S. Virgin Islands and Puerto Rico.

Green turtles are fou= nd throughout the North Pacific, ranging as far north as Eliza Harbor, Admiralty Island, <= st1:State w:st=3D"on">Alaska, and Ucluelet, British Columbia. In the eastern North Pacific, green tur= tles have been sighted from Baja California to southern Alaska. In the central Pacific, green turtles can be found at most tropical islands. In U.S. Hawaiian waters, gre= en turtles are found around most of the islands in the Hawaiian Archipelago. T= he primary nesting site is at French Frigate Shoals.

Human Impacts on Green Sea Turtles

I) Impacts to nesting activities:

In the United States, killing of nesting green turtles is infrequent. However, in a number of areas, egg poaching is still a concern.

Erosion of nesting beaches can result in loss of nesting habitat.

Development of beachfronts results in fortificat= ion to protect property from erosion, resulting in loss of a dry nesting b= each by preventing females from getting to nesting sites.

Beach nourishment during the nesting season buri= es nests and disturbs nesting turtles.

Artificial lighting can cause disorientation and= misorientation of both adults and hatchlings. Tu= rtle hatchlings are attracted to light, ignoring or coming out of the ocean= to go towards a light source, increasing their chances of death or injury= . In addition, as nesting females avoid areas with intense lighting, highly developed areas may cause problems for turtles trying to nest.

Repeated mechanical raking of nesting beaches by heavy machinery can result in compact sand and causes tire ruts which = may hinder or trap hatchlings. Rakes can penetrate the surface and disturb= or uncover a nest. Disposing of debris on the high beach can cover nests = and may alter nest temperature.

The most serious threat of nighttime use of a be= ach is the disturbance of nesting females. Heavy utilization of nesting beaches by humans may also result in lowered hatchling success due to = sand compaction.

The placement of physical obstacles on a beach c= an hamper or deter nesting attempts as well as interfere with the incubat= ion of eggs and the emergence of hatchlings.

The use of off-road vehicles on beaches is a ser= ious problem in many areas. It may result in decreased hatchling success du= e to sand compaction, or directly kill hatchlings. Tire ruts may also inter= fere with the ability of hatchlings to get to the ocean. =

The invasion of a nesting site by non-native bea= ch vegetation can lead to increased erosion and destruction of a nesting habitat. Trees shading a beach can also change nest temperatures, alte= ring the natural sex ratio of the hatchlings.

II) Impacts in the marine environment

Dredging can result in habitat destruction by disrupting nesting or foraging grounds. Hopper dredges can also kill turtles caught in dragheads.

Green turtles eat a wide variety of marine debris such as plastic bags, plastic and styrofoam pieces, tar balls, balloons and plastic pellets. Effects of consumption include interference in metabolism or gut function, even at low levels= of ingestion, as well as absorption of toxic byproducts. NMFS is currently analyzing stranding data and available necropsy information to determi= ne the magnitude of debris ingestion.

Commercial fishing

It is estimated that = before the implementation of TED requirements, the offshore commercial shrimp fleet captured about 925 green turtles a year, of which approximately 225 would d= ie. Most turtles killed are juveniles and sub-adults. Bluefish, croaker and flounder trawl fishing are also serious threats.

Turtles are be taken = by purse seine fisheries in the Atlantic an= d Gulf of Mexico, but the magnitude of take is curren= tly not known.

Several thousand vess= els are involved in hook and line fishing for various coastal species. The capturing of turtles is not uncommon, but the number is not known.

Significant numbers of turtles may be killed by gill and trammel net fisheries off the eastern coa= st of central Florida. An exact number is not known.

Pound net fisheries a= re primarily a problem in waters off of Virginia, where turtles get tangled in the gear and drown. In = North Carolina, live turtles are often released from pound nets.

Over 330 sea turtles = of various types (a few of which were green) were captured in the Atlantic and Gulf of Mexico EEZ in the Japanese tuna longline fishery from 1978-1981. = Due to expansion of this type of fishing, it may have a significant impact on sea turtle recovery. The number of deaths is unknown.

Green turtles become entangled in trap lines and drown. The impact on the population has not been determined.

In areas where recreational boating and ship tra= ffic is intense, propeller and collision injuries are not uncommon.

Marine turtles are at risk when encountering an = oil spill. Respiration, skin, blood chemistry and salt gland functions are affected.

Pesticides, heavy metals and PCB's have been detected in turtles and eggs, but their effect is unknown. =

Marina and dock development can c= ause foraging habitat to be destroyed or damaged. It can also lead to incre= ased boat traffic, increasing the risk of turtle/vessel collisions.

Turtles have been caught in saltwater intake sys= tems of coastal power plants. The mortality rate of the turtles involved is estimated at 7%.

Underwater explosions (e.g. gas and oil structure removal and testing using explosives) can kill or injure turtles, and = may destroy or damage habitat.

Turtles get caught in discarded fishing gear. The number affected is unknown, but is potentially significant.

Illegal harvesting of green turtles is uncommon = in the U.S. No estimates of take exist. Illegal take of green turtles in the Caribbean, particularly near Puerto Rico, is a significant problem.

Excerpt from an artic= le at: http://www.= nmfs.noaa.gov/pr/species/turtles/green.html