Background

La Escobilla is a sandy beach and the main nesting site of the Olive Ridley turtle, Lepidochelys olivacea, (golfina in Spanish), from the southern Mexican coast. Studies related to the habitat of these organisms suggest conservation strategies that lead us to examine the physical parameters that affect the arribazones [i.e., coastal abundance of fish, off-shore shoals, and, by extension, abundance of turtles].

Goals

The aim of this study was to investigate the textural characteristics of coastal sediments and morphology of the beach in order to determine their possible relation with the nesting of this species.

Methods

Sediment samples were collected along 15 km of infra-, meso-, an supra-beach, topographic surveys of beach profiles were made, and some sedimentological parameters were obtained, i.e., Mzϕ (size grain) and αϕ (sediment classification).

Results

Meso-beach and supra-beach areas with a gentle slope (from 2° to 4°), grain size medium sands (1ϕ to 2ϕ), and the opening of the sandbar at the mouth of the Cozoaltepec River during rainy season appear to favor nesting.

Conclusions

Areas with major nesting sites are located at a distance of 2.3 km to the east of the Cozoaltepec River, where apparently the morphology of the beach is more adequate because its slope is not so high and the beach is wide enough for nesting. We also know that the largest observed turtle arribazones occurin this area.