Nesting ecology of hawksbill turtles, Eretmochelys imbricata, in an extreme environmental setting

Abstract

Relatively few details of hawksbill turtle (Eretmochelys imbricata) nesting ecology exist within the Arabian Gulf. Moreover, little is known about how their nesting dynamics compare to nesting populations throughout the rest of the world. Due to the extreme environmental setting, nesting ecology of hawksbills in the Arabian Gulf is of significant interest to researchers and conservationists. The current research reports on a long-term tagging and monitoring program undertaken at Fuwairit beach, Qatar. To investigate nesting behavior, site surveys and tagging were employed from 2010 to 2016. Presence of nests and clutch sizes were confirmed by excavation. Over the entire study period, nesting hawksbills had a mean curved carapace length of 70.8 cm (SD±2.8). A total 187 nests were confirmed, which contained a mean 78.9 eggs per clutch (SD±17.1), over an annual nesting season that lasted an average of 52.2 days (SD±6.3) from the start of April to the start of June. Meta-analysis with other global regions showed these characteristics to be significantly reduced when compared to nesting hawksbills from other populations. Meteorological data analysis showed air temperatures in the Arabian Gulf to increase on average 13.2°C (SD±0.26) from start to the end of nesting annually, which is significantly greater than other global nesting regions. Their smaller body size and reduced fecundity coupled with the extreme change in ambient air temperatures support the hypothesis that hawksbills in the region are more at risk than the already critically endangered hawksbill populations elsewhere in the world.

Environmental Drivers of Habitat Use by Hawksbill Turtles (Eretmochelys imbricata) in the Arabian Gulf (Qatar)

“…Working with the Qatar University Turtle Nesting Monitoring Program and Qatar Petroleum on Halul Island, we participated in beach surveys (motorized and walking) to locate tracks of nesting hawksbills (nesting season in Qatar occurs April-June; Chatting et al, 2018). Once detected, post-nesting individuals were captured by hand as they returned to the sea.…”

“…Since body mass and size are correlated with dive depth (Blumenthal et al, 2009c), it is may be that only the largest adult hawksbills can exploit the deepest part of this habitat. This depth may be challenging for some Arabian Gulf hawksbills since they are among the smallest in body size in the world (Chatting et al, 2018). If hawksbills are successfully foraging at these greater depths, the vertical rugose habitat may serve to stratify foraging individuals by size (and age) and partition resources as suggested by Blumenthal et al (2009c).…”

“…Hawksbills are known to nest on the islands off Saudi Arabia (Al-Merghani et al, 2000), Iran (Mobaraki, 2004;Hesni et al, 2019), the UAE (Abdessalaam, 2007), and Kuwait (Meakins and Al-Mohanna, 2004). Qatar, a small peninsular country that juts into the Arabian Gulf, has one of the largest and most important hawksbill nesting habitats in the region; hawksbills are the only marine turtle that nests in Qatar (Pilcher et al, 2014a(Pilcher et al, ,b, 2015Chatting et al, 2018). Approximately 200 hawksbills nest in Qatar each year (Tayab and Quiton, 2003;SCENR, 2007;Chatting et al, 2018).…”

“…Qatar, a small peninsular country that juts into the Arabian Gulf, has one of the largest and most important hawksbill nesting habitats in the region; hawksbills are the only marine turtle that nests in Qatar (Pilcher et al, 2014a(Pilcher et al, ,b, 2015Chatting et al, 2018). Approximately 200 hawksbills nest in Qatar each year (Tayab and Quiton, 2003;SCENR, 2007;Chatting et al, 2018). The marine ecosystems of Qatar and the Arabian Gulf are regionally and globally significant to the global conservation of hawksbill turtles (Pilcher et al, 2014a(Pilcher et al, ,b, 2015Chatting et al, 2018).…”

“…Approximately 200 hawksbills nest in Qatar each year (Tayab and Quiton, 2003;SCENR, 2007;Chatting et al, 2018). The marine ecosystems of Qatar and the Arabian Gulf are regionally and globally significant to the global conservation of hawksbill turtles (Pilcher et al, 2014a(Pilcher et al, ,b, 2015Chatting et al, 2018).…”