Dugong and seagrass research results – Project MY4 Louisa Ponnampalam . Ng Jol Ern . Jillian Ooi . Heng Wei Khang . Gregory Verutes

“A Multi-Pronged Approach in Overcoming Knowledge Barriers on the Ecology and Status of Dugongs in Johor – Towards Critical Habitat Protection (MY4-2114)”

Supported / Partnered By:

Research team and collaborators Jillian Ooi, University Malaya Heng Wei Khang, University Malaya Kee Alfian, SEAlutions Sdn Bhd Affendi Yang Amri, University Malaya Ng Jol Ern, MareCet Louisa Ponnampalam, MareCet Gregg Verutes, Universidade de Santiago de Compostela, Spain

Project site @ Pulau Sibu and Pulau Tinggi, Johor, Malaysia Bali

Dugong/seagrass conservation issues Problem Lack of detailed information on dugong distribution Some parts of core habitat fell outside protected area (Ponnampalam et al. 2015) Lack of information on dugong density and habitat use Lack of information and understanding on the overlaps with human activities Seagrass meadows at Pulau Sibu extensive but never been mapped in detail Lack of knowledge on main dugong feeding grounds Lack of information on dugong feeding preferences Objectives Determining dugong distribution and habitat use Mapping Pulau Sibu seagrass meadows Investigating dugong feeding ecology around Pulau Sibu and Pulau Tinggi

Strategy, Methods, Tools Aerial surveys to systematically collect data on dugong distribution across the years, and in differing variables (e.g. time of day, tidal state), and data on the occurrence and distribution of human activities Bycatch Toolkit – Risk Assessment Seagrass mapping of Pulau Sibu Underwater surveys of the subtidal seagrass to identify core feeding grounds and sample feeding trails and seagrass Laboratory analyses of seagrass samples and photo-quadrat data

RESULTS Aerial surveys

X Dugong core areas All sightings Mother-calf pair sightings 2.7 dugong sightings/100 km 4.5 dugong sightings/h (LOW encounter rates) 642 sightings 24.5% sightings with calves Group size range: 1 – 43 (Mean = 1.9 ± 3.6, Median = 1, Mode = 1) X All sightings Mother-calf pair sightings

Dugong herd size

Dugong distribution (time of day)

Dugong distribution (spring tide vs neap tide)

ByRA (bycatch risk analysis) Nets Trawls

ByRA (bycatch risk analysis) Traps Recreational fishing

ByRA (bycatch risk analysis) FISHERIES BYCATCH RISK was calculated as: (1) exposure (the degree a species experiences stress due to gear-specific threat (spatial/temporal overlap, threat intensity, likelihood of interaction, catchability, and current status of management strategies)); (2) consequence (defined as the resilience of a species to a stressor (age of maturity, reproductive strategy, population connectivity, local status of species)); and (3) sensitivity (mortality and life stages affected by gear).

ByRA toolkit Verutes et al. in prep Hines et al. in prep

Results Seagrass mapping Co-investigators: Jillian Ooi, Heng Wei Khang (University of Malaya) Seagrass mapping Pic: Heng WK Pic: Nazirul Amin

Dugong feeding grounds Inter-monsoon, June 2016 Pre-monsoon, Oct 2016

Dugong feeding trails Feeding trail dimensions Measurement Value Average Length (m) 7.80 ± 5.32 Average Width (cm) 14.28 ± 2.82 Average Depth (cm) 2.7 ± 0.6 Average Area (m2) 1.16 ± 0.54 Average Biomass per FT (g DW) 50.65 ± 41.07

Dugong feeding preferences Analysis by: Heng Wei Khang (University of Malaya) Main species consumed – Halophila ovalis and Halodule uninervis HO shoot density was significantly higher in FT compared to NFT (Wilcoxon rank sum: Z = 2.16, n = 22, p = 0.03). HO was significantly higher than HU in FT (Wilcoxon signed rank: Z = 4.93, n = 22, p = <0.001)  Denser HO areas were preferred by dugongs. Shoot Density (m-2) Seagrass sp_Area type

Dugong feeding preferences Analysis by: Heng Wei Khang (University of Malaya) Seagrass Biomass (g/ DW m2) Seagrass sp_Area type HO biomass was significantly higher in FT areas compared to NFT areas. HO biomass was significantly lower than HU only in NFT areas  higher HO biomass areas were preferred

Not just a research project….. Mersing Archipelago IUCN Important Marine Mammal Area – Sep 2018

Not just a research project….. Towards the Johor Dugong Sanctuary 150,000+ ha

Not just a research project….. MANAGEMENT Enhance governance, encourage co-management Towards financial sustainability Towards the Johor Dugong Sanctuary CONSERVATION Increasing understanding Minimizing threats Sustaining dugongs, seagrass and fisheries OUTREACH Improving awareness Increasing recognition Empowering communities DEVELOPMENT Improving facilities and amenities Introducing unique products Creating new livelihoods World class conservation and ecotourism area Pending Gazette by the Dept of Fisheries Malaysia

Lessons learned Aerial surveys Seagrass surveys ?? 17 X

Replication potential

Replication potential ByRA toolkit

Terima kasih! Thank you!