New research highlights how the firsthand knowledge of local fishers is invaluable in taking the first steps towards protecting vulnerable dugongs in Malaysia.

Dugongs are the placid, seagrass-grazing “cows of the sea,” closely related to the endangered West Indian manatee and the tragically extinct Stellar’s sea cow. Dugongs are threatened across their range by hunting, propeller wounds from boats, entanglement in fishing gear, and the rapid reduction of seagrass meadows. With these myriad threats, it is not outside the realm of possibility for dugongs to eventually go the way of their close relative the Stellar’s sea cow and be lost to history.

To prevent just such a tragedy, the government of Malaysia has recently announced that in international collaboration with the Philippines and Indonesia it will be launching a new conservation project to better study and protect their dugongs. Yet it is difficult to even know where to begin when implementing such a project, since nearly all dugong studies have been in Australia and left Malaysian dugongs sadly neglected. Scientists know next to nothing about the dugongs of this area—not even rough estimates of the size or distribution of the population. Clearly, this baseline info is critical in order for conservation policies to be effective and worth the investment.

Scientists from universities in Malaysia and Japan set out to gather this much-needed information and provide the first concrete study to assess dugong populations in the area. The researchers gathered satellite-data maps of the bathymetry and seagrass cover of the Johor Straights region in Peninsular Malaysia, and also extensively interviewed fishers from many of the local villages about the occurrence of dugongs in the area in order to fully glean as much information as possible from the people who knew the region best. This newly-published research will be invaluable in the protection of dugongs.

Using the latest, most advanced models, researchers constructed an in-depth GIS map of the area that could be used to predict the population size and distribution of dugongs based on habitat suitability (calculated from seagrass cover and bathymetry) and the sightings reported by fishers. These models also identified the areas of highest probable overlap between dugongs and fishing pressure—in other words, the locations where dugongs would probably be at the highest risk, and where a conservation policy should concentrate particular effort.

The dugongs of Malaysia are notoriously shy and even the local fishers only rarely spot them, but the scattered sightings of an individual fisher provides invaluable information when combined with the observations of many, many other people. The researchers were able to use the model they constructed to identify the areas of highest risk to dugongs on the southern and eastern coasts of the Johor Straights. They were also able to confirm that the Mersing Islands off the eastern coast likely supports the highest population of dugongs in the region, undoubtedly due to the closely monitored Marine Protected Area located there.

The results of this study provide the first baseline scientific study of Malaysian dugongs and offers a usable model to assist policymakers when drafting conservation plans. The researchers identified protecting seagrass habitat and enforcing a responsible fisheries policy as the most important components of a conservation plan for dugongs. Additionally there is extensive coastal development springing up along the Johor Straits, activity which inevitably leads to degradation of seagrass meadows, so it is already apparent that a compromise is needed there at the very least.

Importantly, this study illustrates the benefit of combining multiple sources of scientific data with the knowledge of local stakeholders to create fully informed models. This same technique can also be utilized for other conservation issues across the world in drafting policies that best protect both vulnerable species and the ecosystems they rely on.

 

Reference

Hashim, M. et al. (2017) “Using fisher knowledge, mapping population, habitat suitability, and risk for the conservation of dugongs in Johor Straits of Malaysia.” Marine Policy 78: 18-25. DOI: http://dx.doi.org/10.1016/j.marpol.2017.01.002

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