Lanyu, also known as Orchid Island, is a 45-km² volcanic island that lies about 65 km southeast of Taitung City, thus making it the southemost outpost of Taiwan in the Pacific Ocean. The least spoiled tropical coral reefs abound Lanyu’s rocky shoreline, and the warm Kuroshio Current, flowing northward from the equator and passing Lanyu, enriches coral-algae symbiosis that sustains a productive and biologically diverse coastline. 

Unfortunately, fierce typhoons frequently come blistering from May through November. These typhoons produce high winds that can generate waves capable of damaging coral reefs. Caused by typhoons, driftwoods that relentlessly batter the coral reefs, and silt and mud that flow into the sea exacerbate the situation. Sorry to say that the magnitude and duration of high-energy wind and waves brought by typhoons to Lanyu are often twice as much as to the Taiwan Strait.

Typhoon Morakot, which occurred in early August 2009, was the deadliest typhoon to strike Taiwan in recorded history. In Lanyu, the very typhoon not only wreaked havoc on villages and people but also on the coral reef system in its seabed. In a joint study between the NARL’s Taiwan Ocean Research Institute (TORI) and Taitung County Govement, the survey showed that the live coral coverage in Lanyu waters had declined to 14 percent immediately after Typhoon Morakot. This is a sharp drop from the 55 percent recorded before Typhoon Morakot. Up to March 2010, regrettably, no more than 10 percent of the live coral coverage remained in waters surrounding Lanyu. Much of its seabed was littered with coral wreckage and the coverage of benthic algae reached 50 percent, which is 165% higher than in September 2009. Such a high coverage of algal turfs is going to have negative impacts on coral recruitment that is a key component of reef resilience – the capacity of reefs to absorb and bounce back from disturbance.

■ The shoreline of Lanyu before and after Typhoon Morakot. Left (Before): resplendent with foliaceous and branching corals; after (right): dominant by coral wreckage and algal benthos.

To repair Lanyu coral reefs damaged by Typhoon Morakot and other anthropogenic stresses, the NARL-TORI suggests to apply rehabilitation techniques, including asexual transplantation using living corals from other areas, and the widely used ‘electric’ reefs that use low-voltage electricity to increase mineral accretion and accelerate coral recovery. 

As part of the rehabilitation effort, in the meantime, an underwater ecology observatory established near Yeyou Village on Orchid Island by the NARL-TORI and the NARL’s National Center for High-Performance Computing (NCHC) in July 2009 is employed to monitor the dynamics of disappearance and reappearance of coral reefs. The real-time images of the coral reef ecosystem are transmitted to the NARL-NCHC for record and analysis. The collected information is then shared among the conceed researchers in the country to make meaningful interpretations and to establish the knowledge base necessary for enacting management decisions in coral reef rehabilitation in Lanyu, and for transference to international agencies engaged in the protection of coral reef ecosystem worldwide.