Green (Chelonia mydas) and loggerhead (Caretta caretta) habitat use of the most environmentally extreme sea turtle feeding ground in the Mediterranean basin

摘要

Studies of feeding grounds are vital to understanding the ecology and conservation issues of sea turtles. The hypersaline, lake Bardawil, of North Sinai has recently been recognized as being a major feeding ground for sea turtles in the Mediterranean Sea. The objective of this research was to examine if the environmental variables (salinity, dissolved oxygen, and depth), distance to nearest Mediterranean inlet, and food availability (zooplankton and phytoplankton density) differed between areas according to species richness (green (Chelonia mydas) and loggerhead (Caretta caretta) turtles, single species, no species) and between areas in which loggerhead and green turtles were observed and not observed. Our results highlight the importance of environmental factors determining the distribution of endangered sea turtles as areas with high sea turtle richness had lower salinity, higher dissolved oxygen, were deeper and located closer to the nearest Mediterranean inlet. Our results support the suggestion that since the creation of the man-made inlets from the Mediterranean Sea, the environmental conditions of the hypersaline lake Bardawil have become less severe and more suitable for sea turtles as a feeding ground. The conservation of this biologically valuable lake will require active management to protect it from the increasing anthropogenic threats that will encroach upon the lake in the next decade.