The problem at Breem Island is a product of unfortunate geography. More than 95 percent of the island’s nesting activity occurs along a six-kilometer stretch of coastline on its south and west sides, and while most of the terrain there is sandy and flat, three sections of low rocky sea cliffs sit immediately adjacent to high-density nesting beaches. Female green turtles, hauling themselves ashore at night to lay their clutches, sometimes stray into the areas above these cliffs. On their return journey, they fall over the edge. The consequences are often fatal: turtles have been found dead after falls, or stranded on their backs, unable to right themselves under the weight of their own shells. Between 2018 and 2023, researchers documented nine known mortalities from these cliff falls, a toll that may sound modest until it is placed in the context of the population it affects.

That context is what makes the numbers genuinely alarming. Using recent estimates of nesting activity, and applying standard demographic assumptions—a clutch frequency of 5.9 nests per female per breeding season and an interval of roughly three years between breeding seasons—the research team estimates that only around 135 green sea turtles nest on Breem Island. An average observed mortality rate of 1.5 turtles per year therefore represents approximately one percent of the entire female breeding population dying from cliff falls annually. For a long-lived, slow-reproducing species in which adult survival is the single most important demographic parameter, the sustained removal of even this level of mortality could meaningfully influence population trajectory. Sea turtle populations are shaped by many factors, but every adult female lost represents decades of accumulated reproductive potential, and conservation biologists have long emphasized that protecting adults yields the greatest returns for species of this kind.

The response, launched in 2024 as the Breem Island Cliff Barrier Project, drew inspiration from an unlikely but proven source: the turtle protection fences deployed on Raine Island in Australia, where similar hazard-mitigation strategies have been used to safeguard nesting turtles. The design brief for Breem was demanding. The team wanted an approach requiring limited maintenance, with a natural aesthetic that would not mar the island’s landscape, and crucially one that could be installed without heavy machinery in an ecologically sensitive location. The island also supports significant seabird colonies and other wildlife, meaning any intervention had to minimize noise, disturbance, and transport requirements. The solution they settled on was elegantly low-tech: gabion boxes, lightweight wire structures wrapped in sand-colored fabric, which could be transported to the island empty and then filled in situ with sand by hand.

The technical specifications reveal the care embedded in the design. Each gabion box has a footprint of one meter by one meter and a height of 80 centimeters. When filled with roughly 50 centimeters of sand, each box weighs approximately 800 kilograms—substantial enough to deter a determined adult green turtle, which can weigh well over 100 kilograms itself, yet simple enough to be positioned manually. Critically, the boxes were installed with 30-centimeter gaps between them. These gaps are deliberate: they allow smaller fauna, including seabirds, reptiles, and invertebrates, and potentially even sea turtle hatchlings, to move freely through the barrier line, while still blocking the passage of adult turtles. This attention to bycatch of the non-target kind—ensuring the barrier solves one problem without creating another—reflects a mature conservation engineering philosophy that considers the whole ecosystem rather than a single species.

The geometry of the barriers was equally considered. Rather than running a straight line across the beach, the team deployed two 200-meter-long curved barriers, positioned at the northern and southern edges of one of the main cliff areas surrounded by high-density nesting beaches. The curvature is functional, not decorative: it allows controlled redirection of turtles away from the dangerous area above the cliffs and back toward beaches from which they can safely return to the ocean. Crucially, the alignment was designed so that no main nesting area would be impeded. A turtle encountering the barrier is gently channeled along its curve until it reaches safe ground, rather than being trapped or forced to retrace a long and exhausting crawl. For an animal that may expend enormous energy during the nesting process, this matters.

The results from the first monitored season exceeded expectations. During the 2024 nesting season, which runs from March through November, field assessments recorded 23 successful redirections of green turtles—14 at the southern barrier and 9 at the northern barrier—identified through direct observation or, more commonly, through tracks showing turtles interacting with and being diverted by the structures. Even more telling were the negative results: no turtle tracks were observed in the hazardous area above the managed cliff zone, indicating that the barriers achieved complete effectiveness in preventing access, and no turtle mortalities were recorded within the protected zone across the two nesting seasons since installation. For an intervention costing relatively little and requiring no ongoing active management, the first-year return on investment, measured in turtle lives, is difficult to overstate.

The significance of the Breem barrier system extends well beyond a single island. It represents the first cliff-hazard mitigation project for sea turtles anywhere in the Red Sea, and it offers a template for other rookeries in Saudi Arabia and the wider region where natural topography or anthropogenic structures create hazardous dead-ends for nesting females. The most obvious candidate is Ras Baridi, the region’s most important green turtle nesting site, where sea cliffs have been documented contributing to strandings and falls of nesting females, with several mortalities recorded from this cause both recently and historically. No barrier system has yet been installed there, but the Breem pilot demonstrates that even small, strategically placed barriers can drastically reduce mortality risk. The approach could also prove relevant far beyond the Red Sea, wherever cliffs, seawalls, or other obstacles adjoin turtle nesting beaches—a hazard that researchers have flagged as an emerging concern in the face of sea-level rise and coastal development.

The research team is candid about the limits of the current evidence. A full assessment of the barriers’ impacts on sea turtle populations, on other fauna, and potentially on beach dynamics themselves will only become evident over longer timeframes. Coastal armoring structures are well documented to alter sand transport and beach morphology in some contexts, and introducing any hard structure onto a dynamic coastline warrants continued monitoring. Encouragingly, the gabion design’s permeability and natural appearance were chosen specifically to minimize such risks, but the authors acknowledge that unintended consequences for other species or for sediment movement cannot be ruled out without longer observation. Given the promising first-year results, the team intends to expand protection to the other two Breem cliff areas where mortalities have been recorded, extending the coverage of what has so far proven a remarkably effective solution.

What makes this story resonate beyond the technical details is its demonstration that conservation does not always require heroic, expensive, or technologically sophisticated interventions. Two hundred meters of sand-filled wire boxes, positioned with ecological insight and geometric care, appear to have closed a lethal gap in the life cycle of an isolated turtle population. In a world where marine conservation often grapples with intractable problems—bycatch in industrial fisheries, warming oceans, plastic pollution—the Breem Island project is a reminder that sometimes the right answer is local, specific, and refreshingly simple. For the roughly 135 female green turtles that return to Breem’s beaches year after year, the cliffs that once claimed one of their number annually now stand behind a humble line of sand-colored barriers, and the path from nest to sea is safe once more.

Subject of Research: Cliff-hazard mitigation barriers protecting nesting green sea turtles on Breem Island, Saudi Arabia

Article Title: Innovative barriers reduce risk of injury and mortality for nesting green sea turtles on Breem Island, Saudi Arabia

Article References: Jabby, K., Williams, I. D., Hardenstine, R. S., Barrios-Garrido, H., Al-Ansari, A., & Al-Attas, O. (2026). Innovative barriers reduce risk of injury and mortality for nesting green sea turtles on Breem Island, Saudi Arabia. Discover Oceans, 3(1), Article 14. https://doi.org/10.1007/s44289-026-00130-8

Image Credits: AI Generated

DOI: 10.1007/s44289-026-00130-8

Keywords: green sea turtle, Chelonia mydas, Breem Island, Red Sea, nesting beaches, conservation engineering, gabion barriers, hazard mitigation, Saudi Arabia, sea turtle mortality, hawksbill turtle, coastal management