The Catlin Seaview Survey begins its latest Coral Triangle expedition in Manado at the heart of North Sulawesi, one the world’s marine biodiversity hotspots.
The mangrove forests, or mangals, seen along much of the shorelines are often overlooked but are an integral piece of the entire ecosystem. North Sulawesi is home to the majority of Indonesia’s remaining mangals, with the Manado area harboring some of highest diversity of the species in the world including Rhizaophora, “true mangroves”, and Sonneratia. The synergistic relationship between the mangroves, seagrasses, and coral reefs may very well contribute to the pronounced health of this region.
Mangals are of great ecological and economic importance. They provide coastal protection from erosion, storm surge, and tsunamis; serve as a significant nursery ground for fishes; provide a unique habitat for many species of wildlife; and improve coastal water quality through their intricate root system.
Mangals also provide secondary benefits by being functionally linked to other coastal ecosystems. The buffering capacity of their root systems to strip water of toxins before it flows through seagrass beds and onto coral reefs is imperative for maintaining healthy communities. A recent scientific study has found over 30 species of scleractinian corals thriving in the shady mangrove root system - conditions that were generally thought unfavorable for corals. This recent discovery shows the value of mangals as a refuge for corals in the presence of a changing environment, and how important it is to protect them.
Led by our local dive guide Basrah, from the Murex Resort, in our first few days we have witnessed meandering volcanic coasts of thick and healthy mangrove forests, bordered by seagrass communities, feeding into remarkable coral reefs. A few of our dives have been at river mouths, such as Kuala Mati, literally meaning ‘dead river’. Here in particular, the need for the mangroves buffering capacity to maintain the ecosystem’s balance and health is showcased.
North Sulawesi is not the first mangrove forest we have encountered in the Coral Triangle. While on our first deployment this year to the Philippines, we had the great fortune of visiting a thriving mangrove forest in the heart of the Palawan province. The local guides were very aware of the importance of these delicate environments.