Satellite Tracking Reveals Nesting Patterns, Site Fidelity, and Potential Impacts of Warming on Major Green Turtle Rookeries in the Red Sea

Abstract

Major aggregations of nesting green turtles (Chelonia mydas) occur in the northern Red Sea, although little is known about the reproductive ecology of this endangered species in the region. To address this issue, we satellite-tracked 30 female green turtles to document their movements and to identify factors driving habitat use at two major rookeries in the Red Sea, Jazirat Mashabah (Mashabah Island) and Ras Al Baridi in Saudi Arabia. Between successive nesting events, turtles displayed high fidelity to nesting beaches and adjacent in-water habitats (inter-nesting habitats). Using generalized linear mixed models, we estimated the mean probability of nesting per beach emergence (nesting success rate) to be 0.628, and the mean duration between a successful nesting event and the successive emergence onto the beach (re-nesting interval) to be 10.8 days at each site. The nesting success rate was relatively high (>0.8) when the preceding daytime land surface temperature (LST) was lower than 37°C but decreased with elevated daytime LST (<0.4 when >47°C). Re-nesting interval was longer at lower water temperatures and towards the end of the nesting season of individuals. Our study improves the robustness of abundance estimates from census data (e.g., track counts) and shows that the protection of nesting and inter-nesting habitats during a breeding season would be an effective conservation strategy for the species. We discuss how global warming could increase energy expenditure due to lowered nesting success, ultimately compromising the reproductive fitness of these populations.

Biology and conservation of marine turtles in the northwestern Indian Ocean: a review

“…Ras Al Hadd, Oman, has almost yearround green turtle nesting, with peak nesting in September and October and significant nesting in November and December (Ross & Barwani 1982). Another exception can be seen in the Saudi Arabian Red Sea, where green turtles nest up to November (Shimada et al 2021a). Hawksbill turtles nest earlier in the year than other species, mainly between March and July, peaking during the summer (May to a b Fig.…”

Satellite Tracking of Post-nesting Green Sea Turtles (Chelonia mydas) From Ras Baridi, Red Sea

“…Jensen et al (2019) defined a unique genetic allele from the green turtles nesting at Ras Baridi. Recently, an assessment of the nesting population and the use of internesting habitat in the vicinity of the Ras Baridi nesting beaches was described (Shimada et al, 2021a).…”

Newly described nesting sites of the green sea turtle (Chelonia mydas) and the hawksbill sea turtle (Eretmochelys imbricata) in the central Red Sea

“…These include two known nesting grounds, one on the mainland (Ras Baridi) and one island (Mar Mar). The Ras Baridi rookery (24.273425°N, 37.626473°E) is the largest nesting site for C. mydas on the eastern Red Sea coast ( Pilcher & Al-Merghani, 2000 ; Shimada et al, 2021a ; Shimada et al, 2021b ) and is the northernmost study site. Mar Mar (19.83576°N, 39.92635°E) is an 800-m long island in the Farasan Banks archipelago approximately 50 km from shore.…”

“…It is the southernmost study site and is a known nesting ground for both C. mydas and E. imbricata ( Miller, 1989 ). The remaining three sites, Rabigh (22.9267°N, 38.8566°E), Um Mesk (22.32464°N, 39.06938°E) and Abu Gisha (22.25303°N, 39.02822°E), have no previous records of turtle nesting, but local anecdotal data suggest that they may be undocumented rookeries ( Shimada et al, 2021a ; Shimada et al, 2021b ). Rabigh is a 12-km long sandy peninsula with an adjacent fringing coral reef.…”

“…Of these five species, only C. mydas and E. imbricata are known to nest in the region ( Mancini, Elsadek & El-Alwany, 2015 ) . While a few large nesting aggregations have been documented, specifically Ras Baridi, ( Hanafy, 2012 ; Mancini, Elsadek & El-Alwany, 2015 ; Shimada et al, 2021a ; Shimada et al, 2021b ) and the Farasan Islands ( Gladstone, 2000 ), sparse nesting is thought to occur along the entire Red Sea coastline ( Pilcher & Al-Merghani, 2000 ; Miller, 2018 ; Shimada et al, 2021a ; Shimada et al, 2021b ). Potential nesting grounds at several near-shore islands and coastal sites are undescribed ( Miller, 2018 ).…”