The Skeleton Eroding Band Disease on Coral Reefs of Aqaba, Red Sea

Abstract

Abstract. The occurrence and distribution of the coral disease Skeleton Eroding Band (SEB) has been studied at the Jordanian coast in the Gulf of Aqaba, the northernmost extension of the Red Sea. The SEB syndrome is caused by the colonial, heterotrich ciliate Halofolliculina corallasia: an advancing front of these protists destroys polyps, coenosarc, and surface of the coenosteum. In recent years SEB was registered in reefs of Australia, Mauritius, and the Red Sea. Along the Jordanian coast, disease frequency at four study sites was investigated and afflicted coral genera and species were documented. The study sites were MSS (Marine Science Station)‐north, MSS‐south, the tourist area near the middle of the coast, and the industrial area adjacent to the Saudi Arabian border. Corals and infections were counted inside randomly placed 1 m2 frames in reef flats and in 5, 10, and 15 m depths. In order of increasing affectedness of sample sites, MSS‐south was the healthiest (12%, 4%, 4%, 16% of infected corals from shallow to deep), followed by MSS‐north (19%, 28%, 24%, 24%), the tourist area (51%, 23%, 16%, 41%), and the industrial area (14%, 30%, 39%, 31%). By far the most frequently encountered coral species were Acropora spp. and Stylophora sp., while relative infection‐rates were highest among Seriatopora sp. (75%), as well as Stylophora sp., Hydnophora sp., and Galaxea sp. (50% each). This was followed in steadily decreasing order from 44% to 5% by Pocillopora, Mycedium, Montipora, Echinopora, Acropora, Lobophyllia, Goniastrea, Millepora, Platygyra, Fungia, Favia, Porites, Goniopora, Favites, and Pavona. SEB was found to a depth of 30 m, but may occur even deeper.