28th June - 30th June, 2004
4.3% of area studied shown to be affected by bleaching
There were no visible signs of disease.
7-15 meters depending on the sea and weather conditions
Tahaa island is one of the smaller islands in the Society Islands at 90 sq km and with a population of 4470. It is a mountainous island with a barrier reef surrounding. The main source of economy on the island is pearl farming and vanilla cultivation. The island is very quiet compared to the nearby Raiatea, and the main town of Patio consists of a bank, a post office, a supermarket, and an artisan shop. We were anchored on the Western side of the island in Hurepiti Bay across from Paipai Pass. The coral study was conducted within the lagoon on the Western side from Paipai Pass to Motu Tau Tau, where the Tahaa Pearl Beach Resort and Spa is located.
Large ocean swells break along the outside of the reef, protecting the islands from intense wave action. A survey dive was conducted at the mouth of the pass to the outside of the reef, but conditions were too rough for a Vitareef study here. Coral coverage in the lagoon is patchy, consisting of mostly sand with coral bommies scattered throughout. Bommies were sometimes close together and other times seperated by large stretches of sandy bottom and made up of primarily Porites boulders and small numbers of Montipora, Pavona, Acropora, Fungia, Psammocora, and Herpolitha. Many of the coral colonies were affected by sediment, mucous, and/or overgrowth by invertebrates or algae. Wave action continously moves bottom sand back and forth over the coral colonies reducing visibility and creating almost constant sedimentation, accounting for the high percentage of corals giving off mucous, their defense mechanism against damage by sediment. Algae present included filamentous, encrusting, and macro-algae. Invertebrates found affecting the coral colonies were boring clams, sponge, and feather duster worms.