Socotra Cormorants in the Arabian Gulf: a review of breeding biology, feeding ecology, movements and conservation

Abstract

Seabirds form important components of marine ecosystems, serving as top predators that indicate long-term stability through feeding interactions. Many species of seabirds reside within the Arabian Gulf although their role in this marine system is not well characterized. Furthermore, oil exploitation and development activities have reduced many species significantly. In this review, I use the Socotra Cormorant (Phalacrocorax nigrogularis) as an example of the biology, movement and conservation of seabirds in the Arabian Gulf. Socotra Cormorants are among the most numerically abundant seabirds residing within the Arabian Gulf. The species has a restricted range spanning from Arabian Gulf, the Gulf of Oman and south into the Gulf of Aden. They are categorized as Vulnerable by the IUCN. Between 56,800-82,800 breeding pairs occur in the United Arab Emirates on 9-12 islands. Breeding season stretches from August to December although delayed or disrupted breeding could result in breeding seasons extending to March. They feed on small forage fish including anchovies (Encrasicholina spp.) with potentially high biomass of small fish taken annually totaling to 11,000-18,000 tons annually. Foraging activities occur in coastal, shallow waters under 15m in depth. On Siniya Island in the east, migration begins in December and birds fly to the central portion of the Arabian Gulf within waters of Abu Dhabi. Summer roosting areas could be associated with movement of fish in to deeper, low-productivity waters during the harsh summers. Patterns of foraging during the breeding season and migration after breeding activities highlight areas that need protection. Future protection of the species would require coordination between different jurisdictions within UAE as well as in Oman.