Frontier-Tanzania Environmental Research REPORT 103 Misali Island

Misali Island: A detailed description of the subtidal regions3.2.1.5 Site 5Substratum compositionThe rugosity of site 5 was moderately high. The reef crest was at a depth of 3mand had a patchy cover of live coral, intermittent with sand and bare rock. Theseaward side of the crest led down a reef wall at approximately 70º, and livecoral increased to about 20% cover until 20m.In the deeper waters of this area (20-27m) there was a sand lagoon, whichextended into a full bed of live coral over a relatively flat area.Biotic coverCoral cover was patchy and between 5% and 10% cover on the reef crest (4-8m). All observed morphological forms were recorded at the site for all depths.Dominant morphological forms recorded between depths 4m and 8m, 10m and14m, and 16m and 18m were encrusting and mushroom corals. Coralline algaewas present with a low coverage (1-10%) in the coral reef areas between 4mand 18m.The coral cover at 25m consisted of extensive explanate Echinopora sp., withapproximately 95% cover.3.2.1.6 Sites 6 & 7Substratum compositionSite 6 and 7 were both very dramatic reef-covered wall regions (45-80º) withhigh rugosity. Some sections were of less severe gradients (10º) and overhangs.The underlying substratum consisted mainly of coral rock with small patches ofsand and rubble.Biotic coverDominant coral growth forms recorded between 4m and 14m were arborescentand encrusting. There was approximately 10% live coral cover and 10% rubble.Live coral cover increased to approximately 15% between 8m and 14m, and20% between 14m and 30m. The dominant morpohological forms recordedfrom 16m to 18m were arborescent, encrusting and explanate corals. Corallinealgae was present in patches amongst fleshy algae and corals throughout thereef areas with low, intermittent coverage of 1-10%. There was seagrasscoverage recorded between 10m and 18m at site 7.3.2.1.7 Site 8Substratum compositionPatchy coral reefs, ranging from small coral bommies to patchy cover werepresent. This was true from 4m to 25m although there was a sand gulley at 15mwith a narrow coral band (approximately 5m in width) at the base. The slopethat led from the 4m-deep reef crest at a 40º gradient flattened to 0º in the sandygulley at 15m and continued deeper at a slope of approximately 15º.Frontier-Tanzania Environmental Research Report 103 17