Leatherback turtles prefer to nest on beaches that have deep water and unobstructed offshore 

 access. These high energy beaches are prone to erosion, causing egg loss. Nests are also lost to 

 hurricanes. 



Artificial lighting can cause disorientation or misorientation of both adults and hatchlings. 

 Leatherback turtle hatchlings are attracted to artificial light, which disrupts their natural sea- 

 finding behavior and can result in increased predation and mortality. In addition, adult females 

 are discouraged from nesting in highly developed areas with intense artificial lighting. 



Beach armoring (seawalls, revetments, riprap, sandbags and sand fences) to protect property 

 from erosion can cause the loss of dry nesting beach and/or interference with access to suitable 

 nesting sites. 



Beach nourishment results in heavy machinery, pipelines, increased human activity and artificial 

 lighting on a project beach, and can cause the burial of nests and disturbance of nesting turtles. 



Repeated mechanical raking of nesting beaches by heavy machinery can result in compacting 

 sand and cause tire ruts which may hinder or trap hatchlings. Rakes can penetrate the surface 

 and disturb or uncover a nest. Disposing of the raked debris on the high beach can cover nests 

 and may alter nest temperature affecting temperature dependent sex determination mechanisms. 



Human disturbance of nesting females is a serious concern. Also, heavy utilization of nesting 

 beaches by humans may result in lowered hatchling success due to sand compaction. 



The placement of physical obstacles on a beach can hamper or deter nesting attempts as well as 

 interfere with the incubation of eggs and the emergence of hatchlings. 



The use of off-road vehicles on beaches is a serious problem in certain areas. It may result in 

 decreased hatchling success due to sand compaction, or directly kill hatchlings and adults. Tire 

 ruts may also interfere with the ability of hatchlings to get to the ocean. 



Impacts in the marine environment 



Commercial fisheries: It is estimated that before the implementation of turtle excluder devices 

 (TEDs). the U.S. commercial shrimp fleet captured approximately 640 leatherbacks each year. 

 Approximately 160 of those captures were fatal. The use of TEDs is not expected to reduce 

 leatherback captures and mortality significantly, because TEDs are generally incapable of 

 passing adult leatherbacks through the exit opening. Leatherbacks can also become entangled in 

 longlines, drift/gill nets, fish traps, buoy anchor lines and other ropes and cables. This can lead 

 to serious injuries and/or death by drowning. 



Marine debris: Entanglement in discarded monofilament fishing line and abandoned netting 

 presents serious problems for leatherbacks worldwide causing injury and/or death. Leatherbacks 

 eat a wide variety of debris such as plastic bags, plastic and Styrofoam pieces, tar balls, balloons 

 and plastic pellets. Effects of consumption can be fatal and include interference in metabolism or 

 gut function, even at low levels of ingestion, as well as absorption of toxic byproducts. 



Leatherbacks are vulnerable to boat collisions and strikes, particularly when in waters near shore. 

 It is not known if open ocean collisions with large ships occur. 



Marine turtles are at risk when encountering an oil spill. Respiration, skin, blood chemistry and 

 salt gland functions may be affected. 



38 



