Most species-rich coral reefs are not necessarily protected
Coral reefs throughout the world are under threat. After studying the reefs in Malaysia, Zarinah Waheed concluded that there is room for improvement in coral reef conservation. PhD defence 22 November.
One-third of the corals of the Great Barrier Reef are dead. This was the sombre conclusion drawn by Australian scientists six months ago. Pollution, shipping and climate change are destroying the world’s largest continuous reef, and other coral reefs seem to be facing the same fate.
PhD candidate Zarinah Waheed studied coral reefs in her home country Malaysia over recent years. She looked specifically at the coral diversity of these reefs and also at the connectivity between the reef locations. She found that the areas with the highest numbers of coral species are not necessarily protected.
During her research, Waheed examined how many species of three coral families – Fungiidae, Agariciidae and Euphylliidae – occur in different reefs spread throughout Malaysia. She made a number of diving trips in the region, together with her co-supervisor and coral expert Dr Bert W. Hoeksema of Naturalis Biodiversity Center in Leiden. Before the diving trips, she first examined all specimens of the target species in the extensive coral collection held by Naturalis.
‘The eastern part of Malaysian Borneo is part of the so-called Coral Triangle,’ Waheed explained. ‘This is a vast area that is home to the highest diversity of corals in the world. Scientists have long suggested that diversity diminishes the further away you get from this Coral Triangle. This hypothesis had never been thoroughly examined as far as Malaysia is concerned. My research shows that this holds true based on the coral species we examined.’
Paradise for divers
Waheed discovered, for example, that Semporma, a paradise for divers in the eastern part of the country, has a total of 89 species of coral of the three families she studied. If you go further west – that is, further away from the Coral Triangle – the number of species drops to only 33 in Payar on the west coast of the Malaysian mainland.
Finally, Waheed investigated how the different Malaysian reefs are connected to one another. She did this by establishing how one species of mushroom coral (Heliofungia actiniformis), the blue starfish (Linckia laevigata) and the boring giant clam that goes by the name of Tridacna crocea are genetically related within each of their populations.
Water circulation pattern
The three model species Waheed studied exhibit different levels of connectivity among the coral reefs. She suspects that this may well be due to the effect of water circulation patterns in the research area. ‘The larvae of the coral, the starfish and the clam can survive for a while before they have to settle on the reef. In the meantime they are carried by the currents and may settle in other coral reefs from where the originate.’
Coral reef conservation
Surprisingly enough, reef areas that have the greatest diversity are not necessarily the best protected. For example, only a limited part of the coral reefs in Semporna are protected under a marine park. ‘Reefs outside the park boundary are not protected. During our diving trips we regularly heard dynamite explosions. Blast fishing is an illegal practice and it causes enormous damage to the coral reef but it is nonetheless a way of catching fish.’ Blast fishing occurs not only in Semporna, but also in other coral reef areas of Sabah, Malaysia, and the Coral Triangle.