DISTRIBUTION OF SEAGRASS IN THE WATERS OF LAWAS, SARAWAK. Oswald Braken TISEN, James BALI, Samantha KWAN, Shirley NANING, Eda IZANIE. Regional Meeting on Conservation & Management of Sea Turtle Foraging Habitats in SEA Waters 22 24 th October, Kuala Lumpur, Malaysia Kuala Lawas Sri Resort Batang Lawas Bukit Sari Belangsat FR Sea grass beds Sungai Bangat INTRODUCTION Lawas District northern Sarawak, Eastern Malaysia on the island of Borneo. About 3,811.9 sq. km. and bordered by Sabah (north), Brunei (west) and Kalimantan, Indonesia (south). Major rivers Sungai Lawas, Bengkulit, Sangkurum,, Awat-Awat and Trusan. 52km coastline covered with mangroves and numerous seagrass meadows. Population around 35,300 (2000) - villages are located by the rivers and main income from artisanal fishing. NO COMMERCIAL FISHING PERMITS ARE GIVEN IN THIS AREA. Why is Kuala Lawas IMPORTANT? A unique and special marine ecosystem mangrove forests, seagrass beds, coral reefs, estuaries, sandy beaches, mud flats and continental slope. Its seagrass meadow is believed to be the BIGGEST SEAGRASS AREA in Malaysia. Important nursery, feeding and transient ground for dugongs, turtles, seahorses, commercial fishes/shrimps, seabirds and coastal cetaceans. Could be the LAST FRONTIER for a viable population of the vulnerable DUGONG in East Malaysia? PROHIBITED area for commercial fisheries recently proposed as an MPA. Dugong dugon (14 to 31 dugongs had been observed during aerial surveys, at least 3 mother/calf pairs). 1
J. Sullivan Green & Hawksbill turtles (> 50 animals/aerial survey). 8 spp. from 2 seagrass families meadows of Halophila and Halodule and numerous dugong feeding trails! MARINE RESEARCH ACVITIES IN KUALA LAWAS Feeding trails clearly visible during low tide 2001: the first aerial survey on marine mammals by UMS- FDS 2002: The first ground trotting by FDS-sea grass beds found 2003: Coral reef areas discovered 2004: Wildlife expedition by SFC 2005-2006: Seagrass monitoring 2007: Aerial survey by SFC-UMS-SWD 2008: Aerial survey by SFC-UMS 2009-2011: Number of research activities by UM, UMT, UMS, FD and SFC 9-14 July 2010: Research and Management of Sea Turtles in the Southeast Asian Waters Study in 1999 and 2001 Swimming speed Average = 45.49 ± 5.87 Km/day 11 @ 1.95 ± 0.24 km/hour The slowest = 38.50 Km/day @ 1.60 Km/hour The fastest= 53.70 Km/day @ 2.23 Km/hour Nesting ground Feeding grounds BRUNEI BAY Migration period Average = 27.89 ± 7.49 day The shortest = 13 days The longest=37 days Feeding grounds Average = 1286.64 ± 312.67 Km The closest =698 Km (Pulau Karimata, Indonesia) JAMES BALI, SARAWAK The furthest FORESTRY Corporation = 1729 Km (Pulau pandjang, 6/11/2013 Indonesia) Day VS Night Migratory paths: from Khram Island, Thailand Average 2 1 7 Speed 428 km/day Duration 47 days Distance 1330 km 6/11/2013 JAMES BALI, SARAWAK FORESTRY Corporation Average 4 Speed 64 km/day 5 Duration 46 days Distance 2745 km 6 BRUNEI BAY 12 3 2
Methodology Study sites: Sg. Mengalong Sg. Bengkulit Tg. Perapat Batang Lawas Sg. Awat-awat Sri Resort Sg. Kuku Karu Sg. Bumbun Sg. Pelait Besar Sg. Sangkurum, Lubok Cina Sg. Kabab Sg. Transect on intertidal area (Kpg., Lubok Cina, Sg. Kuku, Maragas and Sri Resort). Transect design: Team Members: Samantha Kwan Oswald Braken Tisen Abd. Ajis Taib Johny@Hasbullah Buis Tonny Ganyai Kamal Christopher Kri Hariel bin Wahab 5 different locations The length of each transects are variable (depending on shoreline) Low tide Snorkelling/wadding Seagrass % cover visually estimated based on seagrassnet monitoring guide MATERIALS AND METHOD Surveying seagrass Equipment 50 meter measuring tape Nylon tape Quadrate (50 cm x 50 cm) GPS Waterproof notebook Pencils and Eraser Camera Magnifying glass (for identification) Seagrass ID and percentage cover sheet. 3
RESULTS Vegetation type: Mono species and mixed species Distribution: patchy Sediment type: sand, mud, mix of sand-mud, mix of sand - coral. Non-target species:- gastropods, bivalves, sea cucumber, sea horse, Other observation: Dugong feeding trails. The most common species is Halodule pinifolia. Other species includes Cymodocea rotundata Halophila ovalis. Halodule beccarii. Thalassia hemprichii Halodule uninervis Halophila minor Enhalus acoroides Species Seagrass distribution Halodule pinifolia Collaboration study : SFC, UMT, UM, UMS, FDS (2009 &2010) Most abundant seagrass species in Kuala Lawas Found mostly on mixed of Sand and Mud substrate. (sandy, Mud, mixed of coral rubble and sand) Forms monospecific stands Mixed species (HU, HO, CR, EA, HB) Pioneering species (Unstable) July 2009 Succession series in Labik-labik, HP replaced by CR Friuting events (October 2009; April 2010; May 2010) Halodule uninervis Halophila minor Awat-awat Siangsiang Sg. Bangat Sg. Bangat Siangsiang Awatawat Usually found mixed with Halodule pinifolia on sand or mix of sand and mud substrate. Found only once in April 2010. 4
Halophila ovalis Thalassia hemprichii Bangkul it Sg., Sg., near Sg. Bangat, near Sri Resort Occurs at muddy area near river mouth Sparse distribution (2-10% Cover), monospecific stands Enhalus acoroides Cymodocea rotundata Bukit. Sari Distribution: Sg., Sg. EA can be found where TH is found but not mixed. Occurs in a wider range of sediment : mixed of Sand and Mud sediment and Muddy Occurrence: Near Bukit Sari and at /Labik-labik On sandy, Mixed of sand & Mud, Muddy sediment Sometimes formed monospecific stands, but mostly mixed (2 or 3 species CRHUHP, CRHP, CRHU, CRHOHP) Halophila beccarri Halophila beccarii Found at soft substrate near mangrove tree and formed monospecific vegetation or mixed vegetation with Holodule pinifolia patch. Listed as vulnerable in the IUCN redlist. Native to South East Asia and can also be found in South Asia. In Malaysia due to pressures from aquaculture and mangrove deforestation, the population trend of this species is declining (Short et al., 2007). HB occurs outside of sampling stations. There are two more small patch of HB, but the coordinate of the patch is unknown. Near Labik-labik, the patch are mixed with Halodule pinifolia 5
Seagrass species diversity LIMITATIONS Coastline between Sg. Cina (4 55' 57.4998" N, 115 23' 41.4996" E) until Labik-labik (4 54' 36.7992" N, 115 22' 57.9" E) has higher diversity of seagrass where seven species of seagrass can be found Seagrasses are more abundant and diverse at shallow area than at deeper waters. At Sg., sparse Thalassia hemprichii occurs at shallow area but dense meadow of Halodule pinifolia occurs at 500 m further from the coastline. The meadows are exposed at low tide during spring tide. This also occurs in stations near Siang-siang and Awat-awat where there are no seagrass at the coastline but sparse distribution of seagrass can be found 500 m from the coastline. Study period was too short Study sites only at the exposed area during low tide Weather Seagrass experts Funding CONCLUSION Distribution of seagrass in Kuala Lawas are : From Kuala Sungai to Awat-Awat (>30 km) Patchy More abundant and diverse at shallow area than at deeper waters Mono species & mixed species Depend on substrate type (micro-habitat) Seasonal RECOMMENDATIONS Seagrass survey should be extended to deeper waters (more than 3 m depth) To set up permanent research station for long-term monitoring. To carry out a long-term monitoring program to collect, analyse and document the ecological and threats of seagrass To encourage scientific research for further understanding of the seagrass biodiversity, habitats, fisheries resources, and other related fields to support the gazettement of Kuala Lawas as an Marine Protected Area for protection of seagrass To extend the research work including density and biomass studies. 6