The narrow mouth of Jailolo Bay is home to a complex marine ecosystem that consists of the reefs, polyps and beautiful coral cover.
By
ICHWAN SUSANTO, INGKI RINALDI
·5 minutes read
The narrow mouth of Jailolo Bay in North Maluku is home to a complex marine ecosystem that consists of the reefs around Pastofiri Island, the polyps in the waters of Babua Island and the beautiful coral cover of Rumah Merah. All come together in the mutually complementary Jailolo Bay ecosystem.
It is strongly believed that Rumah Merah, 80 percent of which is covered with coral and has been given “very good” status based on the criteria of the Indonesian Institute of Sciences (LIPI), is a source of coral larvae. The current in the bay then spreads the larvae throughout the area and even beyond, towards Ternate or even further and across the seas.
As the name suggests, Jailolo Bay faces Mt. Jailolo, a visible landmark of Halmahera Island when viewed from Ternate. Mt. Jailolo, an active volcano, warms the waters off the local beaches.
Warm water and sometimes even hot water can be found along the beach between Villa Sabua Gaba and Bobo village. Hot water is not a suitable environment for coral reefs to grow. On the other hand, the heated water is said to support the growth of the local plankton population and, therefore, also its predators.
The Kompas team came across this basic overview as it began its Coral Reef Expedition in Jailolo Bay, around 1 hour by speedboat from Ternate, the largest city in North Maluku. For a week, the Kompas team explored the bay’s underwater environment and took pictures of marine life as well as that of the local people.
At the dive site, Kompas was accompanied by Muhammad Abrar, a researcher at the LIPI oceanographic research center, artist Eko Supriyanto and licensed dive instructors Tommy Chandra and Wili from Nasijaha Ternate. Eko, who raised Jailolo to global recognition thanks to his dance performances, had arranged his schedule so he could dive with Kompas.
Eko, who is known as Mas Eko Pece, suggested the team members to begin our dive at Pastofiri. This is a small, crescent-shaped island that is naturally formed from broken coral and is the farthest dive site of Jailolo Bay.
We experienced a strange sensation, as our feet seemed to paddle through denser water. “It feels heavy, as permanent water mass goes through this area,” Abrar said, referring to the water mass of the permanent thermocline. Around the island located in the mouth of Jailolo Bay facing Ternate, the water mass from the Pacific Ocean flows towards the Indian Ocean.
The gateway to Halmahera brings in a huge water mass that is pushed by the southeasterly trade winds. The difference in depth triggers the movement of the water mass from the Pacific Ocean to the Indian Ocean, known as the Indonesian Throughflow. Halmahera is the entry point for the huge water mass, which flows from the Pacific through Indonesia’s archipelagic waters and out into the Indian Ocean.
This water mass flow is different from the water that flows due to tidal changes. “Tidal water is strong and can occur suddenly. The current that we went through was heavy because it is constant. It did not feel like flowing water, but it felt heavy. You can really feel the water mass here,” Abrar said.
Apart from the Indonesian Throughflow, the water mass from Mindanao in the Philippines and from northern Papua meet in the waters to the north of Halmahera to form the Halmahera Eddy. All this water flows through the Halmahera Passage (Gerbang Halmahera) near Morotai.
These water masses affect the local ecosystem. The huge volume of water, for instance, brings with it nutrients and coral and fish larvae from far-flung corners of the seas.
Coral and fish larvae from the Pacific islands, including from coral reefs in Hawaii and in island countries such as the Solomon Islands, Vanuatu and Fiji, are carried by the water mass. With support from the local ecosystem, the larvae will grow and breed.
Center of biodiversity
The collection of various fish and coral species makes Halmahera and Papua’s “Bird’s Head” region rich with biodiversity. “Center of biodiversity, and not center of origin,” Abrar said.
This is analogized with the ethnic plurality. For instance, Jakarta is known as a melting pot while only local tribes may inhabit the hinterlands of Papua. Jakarta is a center of diversity, while the Papuan region is a center of origin.
However, local characteristics, including the geological processes that form terrestrial terrain and numerous factors like the volcanic effect, can give birth to animals. The Halmahera epaulette shark (Hemiscyllium halmahera) found in local waters proves that the region is unique. Unfortunately, during a recent dive session, our team did not encounter the shark, which is also often found in Raja Ampat and Kaimana in West Papua, and even in the waters around Komodo Island.
On our way to the dive site near Pastofiri, we found that around half the seabed was filled with broken coral. The NHR6 dive site showed a different condition, where 10-centimeter-long juvenile coral were found. It is strongly believed that the coral in the region is rehabilitating, as it was dynamite fishing that destroyed the local coral population.
The measurements Abrar took found a high level of coral recruitment, with 33 coral colonies found in a sample area of 70 x 50 centimeters.
At the Rumah Merah dive spot, which is close to human settlements in Jailolo, 50 to 60 types of coral were found. The coral cover is more than 80 percent, which is very good. Based on this high coverage, Abrar believes the area produces coral larvae for colonizing the local waters.
The system of ocean currents that flow locally and around the world is deeply complex and still full of mystery. In Jailolo, a single, complete ecosystem in the Halmahera marine basin proves that different networks of marine ecosystems have different roles.