HATCHLING SUCCESS AND NEST PREDATION IN OLIVE RIDLEY SEA TURTLES ALONG THE GANJAM COAST OF ODISHA

Abstract

Sea turtles because of growing public awareness of their status as an endangered species, increasingly have become the subject of research. The hatching success of sea turtles or the extent  of predation on nesting beaches ,as few quantitative studies under natural conditions exist that deal with either of these topics. Hatching success is most often studied under hatchery conditions. The eggs when handled carelessly during egg transplantation ,lowers the percentage of eggs  which  hatch ( Pritchard 1969a, Bustard1973).Consequently results reported in hatchery studies may not include accurately natural survival rates. Arribadas contribute to the population of Olive ridley sea turtles. Recently ,  survey was conducted on mass nesting sites at Rushikulya coast (   Puranabandha

,Gokhargudda and Podmpeta ) of 20 kms stretch in Ganjam district,Odisha. In isolated beaches as per my survey still poaching persists. In beach survey a total of 265 nests were surveyed during 2014-2015. It covers the geographical coordinates of 19.07 to 20.19 north latitude and 84.01 to

85.06 east longitude. Observations on the hatching success of undisturbed natural nests of Olive ridley sea turtles was studied. Quantitative information on nest predation is fragmentary. Many authors discussed the role that heavy predation pressure probably played an important role in the adaptive selection of islands and isolated beaches by sea turtles for nesting. The  research  is involved following the undisturbed natural nests from egg laying to emergence of the clutch and to determine the percentage of hatchling success in natural emergence. It is also examined on the possible influences of other parameters like rainfall ,incubation time, clutch size ,time of season and nest predation) on emergence success. Olive ridley sea turtles (Lepidochelys olivacea) hatching success and nest predation were investigated at Ganjam Coast ,Odisha during January –May 2015.  A mean incubation period of 45-60 days and a mean clutch size  of  80-140 eggs  and weight   of   the eggs ranged from 22 to 36 grams and hatching success of  38%  were recorded. Incubation  period was related to nest position and clutch size.  Feral dogs ,Foxes ,Wild pigs,  Red crabs ,   Jungle cats and Domestic cats are the main predators which caused  the most  damage. On new  moon day of April 18th 2015, due to high tides large number of half incubated eggs were washed away at Rushikulya Coast ,Ganjam District and hence a mortality of 50% is observed. Proportionately more nests were destroyed near the end of nesting season than during  the  beginning