Anthropogenic beach-activities influences the endemic Red Sea Ghost Crab (Ocypode saratan)

Abstract

International tourism and nature-recreation accounts for ca. > 10% of the international trade and has influenced urban planning, political thought, and land-use. Eilat, Israel, is just such a city of tourism-dependent development. We investigated whether beach tourism affected the ecology of the endemic Red Sea Ghost Crab (Ocypode saratan; RSGC). We hypothesized that we would find lower numbers of RSGC on the tourist beach because it results in the destruction of the burrows and the display pyramids of the male RSGC. All observations were conducted during August and September 2015, 2016, and 2018. We conducted a total of 221 h of observation of which 116 were on a beach without tourist activity i.e., of a fenced naval base beach and 105 on the tourist beach. We found that the number of crabs and those excavating sand from the burrows was highest at the tourist beach, while the number of pyramids was greater, and were higher, on the naval beach. Considering that the height of the pyramid and it’s complex are a reproductive signal for the females we speculate that there is segregation of beaches where on the tourist beach there are more food resources from anthropogenic activity and are occupied by large individuals, while on the navy beach the low human activity allows males to maintain higher pyramids, but which are built by the smaller individuals. Although we found that tourism appears to have benefited the RSGC population, the underlying effects of the food- web must be studied to understand the diet of the endemic species. Authorities need to regulate tourist activities and to educate them of the importance of the maintenance of a healthy environment and the conservation of biodiversity by placing appropriate billboards and signs at the tourist beach.