Distribution patterns of epibiotic barnacles on the Hawksbill turtle, Eretmochelys imbricata, nesting in Iran

Abstract

The hawksbill turtle (Eretmochelys imbricata,) is a critically endangered species of marine turtle that occurs in the Persian Gulf. The present study analyzed the frequency and distribution of epibiont barnacles residing on 122 the carapace and plastron of nesting hawksbill turtles (mean CCL = 70.22 ± 4.3 cm; mean CCW = 64.77 ± 3.2 cm) from the northern Persian Gulf in 2017. Barnacles frequency on the carapace, plastron, flippers, and head were studied in 29 turtles of the 122 turtles. 99.2 % of the nesting hawksbill turtles hosted barnacles and 72% carried between 1 and 20 barnacles (n= 122 turtles). The plastron, carapace, flippers, and head areas of the 29 turtles hosted 2804 836, 585 and 454 barnacles, respectively. The number of barnacles smaller than 0.5 cm on carapace represented 38.8% of the total of 836 barnacles. Based on the combined totals on the plastron, flippers, and head, barnacles smaller than 0.5 cm represented 69.2% of the barnacles counted on the turtles. There was a significant difference among the barnacle frequency on different scales of carapace, plastron, and four flippers (P<0.05). The presence of numerous barnacles may influence the hydrodynamic surface and water flow around the turtle’s body. Moreover, the high density of barnacles may influence the health of the turtles. The number of barnacles residing on a hawksbill turtle may result from the foraging behavior and habitat of the turtles.