Investigation of the effects of sand particle size on the suitability of nesting habitats of hawksbill turtle (Eretmochelys imbricata; Linnaeus, 1766) in the Persian Gulf

Abstract

Introduction: Hawksbill turtles (Eretmochelys imbricata) are one of the seven remaining
species of sea turtles in the world that are classified as endangered in the IUCN Red List due to
their long-term use. Nest site selection is one of the most important behaviors in reproductive
females. Because the environment around the nest affects the survival of the hatchlings.
Materials & Methods: Sands were collected from eight nesting beaches in the Persian Gulf
from three depths. After drying the samples in the open air, 100 gr of the dried sample was
weighed separately for each depth. ASTM standard sieves (No: 4-200) were used to determine
the particle size distribution. Finally, the contents of each sieve were collected and the statistical
parameters were calculated using the GRADISTAT program.
Results: The sand texture in Hormuz and Ommolgorm Islands was Gravelly and in other areas
it was Slightly Gravelly. Particle size in all important points of nesting areas was less than 1000
μm with an average of 581.6±171.4. The lowest particle diameter in Nayband Bay was 284.9
μm and the highest in Ommolgorm Island was 856.4 μm.
Conclusion: Based on the results of the present study, the grain size and origin of sand particles
in the Persian Gulf islands, including oyster shells, coral and gravel, indicate high diversity in
the structure of nesting hawksbill turtle populations in Iran. In the Persian Gulf hawksbill turtle,
the size of particles as a feature does not have a significant effect on the tendency to dig nests.