MARINE BIODIVERSITY OF MYEIK ARCHIPELAGO SURVEY RESULTS 2013-2017 AND CONSERVATION RECOMMENDATIONS
Stretching over almost 4 million ha the Myeik Archipelago and associated Moscos Islands along Myanmar’s most southern coastline is a biologically rich and diverse seascape abound with unique, rare and threatened flora and fauna and the lifeblood of many island and coastal communities. Over the past 30 years however this once unspoiled ecosystem has been slowly degraded from a number of anthropogenic impacts including destructive fishing gears such as dynamite and other illegal, unreported and unregulated (IUU) fishing, increased terrestrial runoff from forest clearing and coastal development, increased population and climate change. To prevent further destruction of the area and to aim towards sustainable use and management of the archipelago, surveys were initiated in 2013 to quantitatively understand the status of the habitats and species and identify priority areas for protection. In summary surveys have found:
• Coral reefs in the survey area showed high levels of hard coral diversity, with 288 species observed, in 68 genera and 17 families. Species accumulation curves predicted a total of 309 species would be obtained with the same method of sampling. • The status of hard coral cover varies greatly across the archipelago from 0% to 92% with an average of 48.9%.
• Coral communities were clearly structured by three main reef types: a) fringing reefs on relatively exposed boulder slopes of outer islands, from the surface to about 15 m depth where the boulders transitioned into sandy slopes; b) fringing reefs on relatively sheltered slopes of the inner islands with high turbidity and strong currents; and c) steeply sloping/vertical rock walls on small isolated rocks or outer island cliff faces, extending into deeper water over 20-30 m deep.
• Coral disease prevalence ranged from 0% to 15% across all sites surveyed, with a mean disease level of 4.9%. Levels of compromised coral health was very high across the archipelago, with a mean level of 23.3%.
• Overall condition of reefs in the Myeik archipelago is average, as a result of diverse impacts, including thermal stress and coral bleaching, fishing for reef fish, and trawler/pelagic fishing on the banks surrounding the islands.
• The total reef fish fauna of the Islands of the Myeik Archipelago of Myanmar consists of 495 species belonging to 62 families.
• The Coral Fish Diversity Index (CFDI) for the Myeik Archipelago predicts a total of 618 species.
• Sharks and large rays were notably absent. Larger individuals of predatory species such as groupers (Epinephelus, Plectropomus), snappers (Lutjanus) and emperors (Lethrinus) were present but only in relatively small numbers.
• Results for the nine fish categories within the archipelago (including groupers, snappers, butterfly fish and parrotfish) indicate an ecosystem heavily impacted by overfishing.
• Biomass surveys noted many sites have relatively low estimates of fishable biomass (< 3 g/m2). Global estimates of biomass below 30 g/m2 present unhealthy and unstainable fishing states. Invertebrates: • A total of 258 reef invertebrate fauna have been collected and of these only 127 could be identified to species level. The majority of the 258 invertebrates observed were decapods with 103 specimens and gastropods with 55. • For sponges 36 unique species were collected during this expedition, with representatives from at least nine orders. • Diadema were the most common of all the invertebrates recorded with 52.01 individuals per transect. Mean invertebrate numbers per transect were generally very low with all but banded coral shrimp, collector urchin and Diadema recording means under one. Sea cucumbers and lobsters have been heavily impacted by an unregulated fishery. • No reefs exhibited high numbers or outbreaks of Crown of Thorns Starfish. Download here