DEPREDATION OF OLIVE RIDLEY AND LOGGERHEAD TURTLE CLUTCHES ON BEACHES WITH AND WITHOUT PREDATOR MANAGEMNT

Abstract

Management of predation on sea\nturtle nesting beaches is vital to conservation efforts for the vulnerable\nloggerhead turtles (Caretta caretta) and olive ridley turtles (Lepidochelys\nolivacea). Sea turtles increasingly face threats from invasive and\nhuman-tolerant mammalian predators as human disturbances on nesting beaches rises.\nThe intensity of mammalian predation has increased in Las Baulas National Park\nin Costa Rica which is an important nesting site for several species of\nthreatened and endangered sea turtles. I analyzed loggerhead and olive ridley\nnest predation on four beaches in the United States and Costa Rica that were\nchosen for variations in degree of human disturbance and management strategies.\nMy objectives were to 1) determine if egg predation rates differ at the four\nsites, 2) determine the most destructive predators at each location, and 3)\nsuggest management options to alleviate mammalian threats to turtle clutches on\nPlaya Grande and Playa Cabuyal in Costa Rica. My results show that the beaches\nwithout a nest protection or predator control program had very high rates of predation.\nInvasive mammalian predators and mammalian predators associated with human disturbance\nwere the most destructive at the four sites. I recommend that regulations\nregarding dogs and the take of eggs from the beach are enforced at Playa\nCabuyal and that physical nest protection is rapidly implemented at Playa\nGrande. I also recommend that the National Park consider managing raccoon\npredation by removing problem individuals, but caution that they do so in a way\nthat maintains the animals’ role in the ecosystem.