Assessing the efficacy of direct conservation interventions: clutch protection of the leatherback marine turtle in the Dominican Republic

Abstract

The beaches of Jaragua National Park in the Dominican Republic are the country's last known major nesting site for the leatherback marine turtle Dermochelys coriacea. This nesting aggregation is threatened by widespread illegal egg take, and clutch relocation and artificial incubation have been carried out as protection measures since 1974. We assess the efficacy of such efforts and investigate how artificial incubation may be influencing the success and sex ratios of clutches. We compare hatching success, incubation duration and embryo mortality in in-situ clutches (n = 43) with those incubated artificially at sites in the east and west of the Park (n = 35 and n = 31, respectively). Our results show that in the west, artificial incubation significantly decreases hatching success in clutches. In the east the duration of incubation is increased, which we predict would result in an increase in the number of males from these clutches. Clutch relocation is currently the only viable conservation option for clutches on eastern beaches because of illegal egg take but action is needed to ensure that the natural sex ratio is not distorted. However, on the western beaches in situ clutch incubation seems possible through beach protection. Further community engagement and enforcement are required to improve conservation measures at eastern beaches if long-term, less sustainable intervention is to be avoided.

Potential limitations of behavioral plasticity and the role of egg relocation in climate change mitigation for a thermally sensitive endangered species

“…We found significantly lower hatching success in clutches protected in situ (43.6%) than clutches relocated on the beach (46.2%) or in hatcheries (58.6%) at both sites (Table ). This difference probably arises primarily from differences in microenvironmental conditions during incubation (Eckert & Eckert, ; Kornaraki et al, ; Revuelta et al, ), such as the amount of organic content (e.g., roots and leaves) in the sand, which is likely lower in hatcheries due to removal of organic material during hatchery preparation. This is consistent with hawksbill clutches in Antigua (Caribbean), where hatching success increased as a function of decreasing organic content in the sand (Ditmer & Stapleton, ).…”

Optimism for mitigation of climate warming impacts for sea turtles through nest shading and relocation

“…However, our experiments were not designed to look at the full extent of depth impacts, since we only varied the range of depths fairly minimally (50–63 cm) corresponding to the mean natural depth of sea turtle nests on the island, while the difference between the minimum and maximum depth of incubating eggs on the study beach is likely to have a much greater effect. Although relocation practices can negatively affect egg and hatchling survivorship 28 , examples of successful relocation conservation programmes exist worldwide 29 , 30 . Our results further demonstrate that shading in combination with relocation to a different cooler beach can have much greater benefits for a balanced primary sex ratio.…”

Prevalence of visible injuries to leatherback sea turtles Dermochelys coriacea in the Northwest Atlantic

“…Fish et al 2005), and direct take of eggs and adults (e.g. Fossette et al 2008, Tomillo et al 2008, Revuelta et al 2015. Leatherbacks are also susceptible to bycatch and entanglement in active and discarded fishing gear (Lewison et al 2004, 2014, Fiedler et al 2012, which can leave distinctive external injuries on the shoulders, neck, head, and carapace caused by rope, netting, and hooks (Innis et al 2010, Eckert et al 2012.…”