Olive Ridley Nest Destiny on Pelada beach, Costa Rica

The olive ridley sea turtle population is in decline due to factors including illegal egg take and nest destruction. This study describes the investigation of the destiny of olive ridley turtle nests on Pelada beach in Nosara, Costa Rica. Nest destinies were categorically classified as one of the following: poached, depredated, or incubated, categorized using non-invasive visual beach surveys conducted between December 2015 and November 2018 in a combined effort headed by a local environmental nonprofit TortuGuiones. The effort was designed to quantify the human-caused destruction of olive ridley sea turtle nests relative to other outcomes on Pelada beach. Fifty-two nests were classified and recorded by ten volunteer surveyors. The results indicated that 49% (± 15%) of nests were poached and 9% (± 8%) of nests were depredated, likely by domesticated dogs. This supports the hypothesis that humans have a significant site-specific impact on olive ridley nest success, both directly through the harvest of eggs and indirectly through their domesticated dogs. These observations suggest that further studies designed to assess the impact of this frequency of human-caused nest destruction on reproduction and population survival are warranted as a basis to establish the best available practices for local population sustainability.