June 29, 2009

Up to 40% Coral Bleaching Recorded in Bali

Fisherman at Bondalem Village checking the bleached massive coral
Two colonies of tabulate Acropora in Lipah Bay Amed, the top one bleached
Bleached corals at Tejakula

By Reef Check Indonesia

In early June, after receiving a report from local fishermen in Tejakula, on the north coast of Bali,  Reef Check Foundation Indonesia (RCFI) conducted a rapid assessment along the coast from Pemuteran to the Amed area (approximately 120 km of shore line). The survey showed that Amed had the highest hard coral bleaching percentage, a total of 40% of hard coral in the area. The lowest level of bleaching was found at Tulamben, with 10% of hard coral bleached. The bleaching affected the following corals:  Acropora (tabulate and branching), Pocillopora, Stylophora, Montipora (submassive and encrusting), Porites, Pavona, Hydnophora, Favites, Galaxea, Fungia, Ctenactis, Sandolitha, Astreopora, Symphyllia, Platygyra, Diploastrea, Heliopora, Lobophyllia, Millepora, Goniastrea, and Pectinia.

The hard coral species more susceptible to bleaching, such as Seriotopora, Pocillopora, Stylophora, and Pavona, experienced severe bleaching, while the more resistant hard corals, such as Porites, were partially bleached, or not bleached at all. The soft corals Sarcophyton and Sinularia, anemones,and zooanthids were also bleached.

The water temperature ranged from 29 to 30°C during the surveys – a somewhat moderate temperature elevation, which may explain why the bleaching was not so severe.

The last coral bleaching event in Bali was recorded in 2005, near the Ngurah Rai Airport. The survey showed that 75% of hard corals bleached, including all foliose Montipora. A survey conducted in the same area a year later showed no more soft coral, possibly a victim of the bleaching.

The biggest bleaching event in Bali occurred during 1997- 1998, as part of the global mass bleaching phenomenon. At that time, Indonesia saw 50% or more hard coral bleaching. In Bali Barat National Park the bleaching hit 100% of coral cover, while in Lombok, Gili Island the bleaching affected 90% of the area. Other areas with bleaching were Seribu National Park, East Kalimantan and Karimunjawa. At that time, the mortality level of the bleaching coral in Karimunjawa was up to 50-60% (Irdez et al, 1998).

According to an analysis by economist Dr. Herman Cesar, a severe coral bleaching event in the next 50 years in South East Asia would cause financial losses due to reduced products and services from fisheries and tourism, as well as biodiversity degradation of up to US$38.3 billion (Cesar et all, 2003).

“Coral reefs in Bali are bleaching; this condition needs a collaborative effort from various parties to manage the impact,” says Naneng Setiasih, the Chairwoman of Reef Check Indonesia Foundation.

The first thing to do at the local level is to preserve coral reefs by reducing other threats. Coral reefs with lower threats will have a better ability to deal with bleaching. Some steps you can take to help coral reefs include:

1. Improve management of existing marine conservation areas
2. Stop overfishing and destructive methods of fishing such as blast and cyanide fishing
3. Reduce fishing of herbivorous fish (dead coral covered by algae needs to be grazed by those fishes, so that the area can be populated by corals).

If you would like to help monitor the bleaching in Indonesia, contact Jensi Sartin at jensi@reefcheck.org. Thank you to the following partners for their help in conducting this rapid assessment: Reefseen Aquatic, Spicedive Lovina, Gaia Oasis, Puri Mada Tulamben, Emerald Tulamben Hotel and Spa, and Bayu Cottages Amed.

Editors note: this report from Indonesia is a perfect example of the value of Reef Check teams. Teams of staff and volunteers are able to spring into action at short notice to track impacts on coral reefs. An area of hot water in the Indian Ocean is causing bleaching from Indonesia to New Georgia, but is expected to slowly dissipate.