The survey along the Red Sea coast in Saudi Arabia, conducted from January through to November 2021, revealed that many threatened and endangered species inhabit the area, highlighting the importance of environmental protection and regeneration efforts. While fish and their habitat were surveyed at nearly 300 coral reef sites, more than 300,000 fish were counted of 280 different species.

During the study, machine learning technology was used to automatically analyse coral reef survey imagery, a tool that generates data comparable to that produced by expert human analysts with significantly less time to analyse and receive data. The researchers assessed the condition of coral habitats across all complex shallow reef system encompassing around 100 km2 of reef habitat. They found that, although conditions of reefs varied, the highest quality reefs were found at outer reef walls and crests, while the highest coral cover at any site was outside Ummahat Island.

Many enormous corals were found throughout the project area, particularly around Mardunah and Waqadi Islands. The largest colony encountered was over eight meters in height and estimated to be over 600 years old. Fish assemblage highlights included discovery of locations of spawning aggregations for snapper and emperor, and regular encounters with schools of up to 100 bumphead parrotfish – the world’s largest parrotfish – listed as vulnerable, and rarely encountered in such large groups across most of their range.

“In terms of coral cover, some areas had cover that was lower than anticipated, with strong indication that they had once been home to more thriving reef communities several years or decades previously. This is a reminder of the fragility of coral reef systems, but also highlights areas that we may hope to improve through reseeding or other methods, as they have potential to sustain vibrant communities,” commented Dr Omar Al Attas, head of environmental sustainability at The Red Sea Development Company which undertook the survey.

Besides fish and corals, 14 bird species were surveyed in the region. While around 25,000 breeding pairs were counted, the most widespread bird population were the white-cheeked Tern and the osprey (each breeding on more than half of the 92 surveyed islands). Most notable of the findings was the importance of the area for sooty falcon, a vulnerable species with declining global population numbers, but breeding in high numbers on some Red Sea Project Islands. The 41 breeding pairs of sooty falcons represented 34% of the Saudi Red Sea population (~120 pairs) and 2% of the entire world’s population (~2,000 pairs).

When it comes to megafauna in the Red Sea, the survey teams found close to 200 nests of the critically endangered hawksbill turtle, as well as had numerous sightings of the endangered Indian Ocean humpback dolphin, and eight different species of sharks, including the endangered whale and zebra sharks. Furthermore, they saw a significant numbers of the Halavi guitarfish – an endemic species of ray classed as critically endangered. The observation of calves and young individuals of several species of shark, ray, and dolphin indicate the presence of important nursery areas in the region that will be essential to the breeding success and protection of these species.

Additionally, the Red Sea is believed to host the world’s third largest population of Dugongs, after Australia and the Arabian Gulf. The most recent region wide survey was more than 30 years ago, and the lack of comprehensive studies into the species in the Saudi Arabian Red Sea makes this a high priority for us. During 2021, the team sighted Dugong on ten occasions, including one mother and calf.

While much of the Red Sea coast is in excellent condition and home to thriving wildlife, the survey unearthed evidence of some earlier impacts in a few areas. This is a clear reminder that these environments are dynamic and full of potential, but also vulnerable to change, and needing careful management.