No man's land support the endemic Red Sea ghost crab (Ocypode saratan) in the Gulf of Eilat

Abstract

Tourism pressure on the Red Sea ecosystem have posed significant threats to numerous endemic species, including the Ghost Crab Ocypode saratan, which is exclusively found along a small stretch of beach in the Eilat/Aqaba Red Sea Gulf. Due to the limited understanding of their ecology, we investigated how tourism impacts the behavior of this species. Employing a natural setup, we compared burrow dimensions, pyramid structures, and density across three distinct beach sections subjected to varying levels of human interference. Access to a secluded beach, referred to as "No Man's Land," provided a crucial control for our study. This facilitated a comparative analysis of ghost crab activity among beaches experiencing differing levels of human disturbances: (1) a tourist beach characterized by continual high disturbance, (2) a naval beach subject to moderate and sporadic disturbances, and (3) the isolated "no man's land" beach devoid of human presence. Our observations revealed notable differences in ghost crab density among the three beaches. Furthermore, we observed that on the secluded beach, larger individuals tended to establish burrows farther from the waterline and construct taller sand pyramids. Given the significance of sexual selection processes, their conservation becomes imperative for the survival and potential expansion of the ghost crab population across the Gulf of Eilat/Aqaba. We propose a straight-forward and cost-effective strategy: the designation of short, secluded beach enclaves along this gulf. We believe that this approach will mitigate adverse impacts of tourisms while simultaneously benefiting various sandy beach species.

Keywords: Ocypode saratan; Eilat; Endemic; Red sea; Tourism.

Figure 1

Image of the study area in the eastern part of the North Beach of Eilat, Israel. Note that in the satellite photo from Google Earth 10.49.0.0. (https://earth.google.com/web/) marked beaches are sandy, while to the west the gray gravel stands out. The attached overview map was made by the author (JZK) based on field inspections and using QGIS 3.16 (https://qgis.org/pl/site/forusers/download.html) and GIMP 2.10 (https://www.gimp.org/).

Figure 2

Differences in mean standardized value of PYRAMID, ENTRANCE SIZE, DISTANCE, and number of CRABS between beach types and time of day.