Distribution and Ecology of Nesting Sea Turtles in Ghana

Abstract

Distribution and Ecology of Nesting Sea Turtles in Ghana. Information on the occurrence and reproductive biology of sea turtles in Ghana is very scanty, therefore there is a need for detailed scientific studies on which their conservation and protection could be based. The present study has shown that the Olive ridley, Leatherback and Green turtles are the three main species that continue to nest on the beaches along the coast of Ghana. The Olive ridley having the highest relative abundance of 91% at the intensive study area followed by the Leatherback turtle with 6% and the Green turtle 3%.The nesting season begins in August and extends to March, sometimes early April. It peaks in October for the Olive ridley and between December and January for the Green and Leatherback turtles. The Olive ridley turtles arrive first, followed by the green and Leatherback turtles. The nesting period of the Green and Leatherback turtles overlaps that of the Olive ridley. Sea turtles nest in a wide range of beach sediment type along the coast of Ghana. Beach sand with median grain size between 0.2-0.4 mm (medium to coarse sand) and sorting coefficient between 0.4-0.7 (well-sorted to moderately well sorted) are those preferred by nesting turtles along the coast of Ghana. Based on the above grain characteristics, the potential sea turtle nesting sites in Ghana may include beaches along Princess Town to Busua, Senya Bereku to Accra, Prampram to Old Ningo and Anloga to Denu. Estimated average clutch size for Olive ridley, Green and Leatherback turtles were 86, 83 and 81 respectively. However, those counted for the Olive ridley and Leatherback were 100 (SD=6.64) and 85 (SD=10) respectively. Emergence period for the Olive ridley was 52 days, Green turtle 56 days and Leatherback 63 days. Percentage hatching success was very high among all the three nesting species with Olive ridley recording the highest with 92.40%.The percentage hatching success for the other two, Green turtle and leatherback were respectively 89.38 and 88.32. Destruction of sea turtle eggs by dogs at the intensive study area was very high, but this problem was not widespread along the entire coast of Ghana. Percentage false crawls where found to be higher within zones closer to human habitation.