Creation of artificial coral reefs begins
PULAU PANJANG, Seribu Island (JP): Minister of Marine Affairs and Fisheries Sarwono Kusumaatmadja launched on Saturday an artificial coral reef plantation in Seribu Island waters, dubbed the model of a movement to save the country's deteriorating coral reefs and boost the fish production.
"Other countries in Southeast Asia and the United States have developed the use of artificial coral reefs from ship or car wreckages to build a home for fish. I was told that Malaysia's fish production increased up to 300,000 tons thanks to artificial coral plantations," Sarwono told The Jakarta Post during the cruise on board Baruna Jaya I research vessel.
Artificial coral reefs account for some 70 percent of the fish production in Japan, Sarwono said, adding that the artificial barriers are also effective to block trawlers.
"If a trawler tries to break into a sea zone which is protected by the special barrier, it can instantly damage the ship," the minister added.
A total of 96 tons of assembled concrete blocks and tires measuring 340 cubic meters were planted at several spots on the islands' water in a depth of less than 30 meters on Saturday to add to the existing 40 tons of similar materials which were placed at the bottom of the Situbondo sea off East Java in September.
Each assembled concrete block is worth an estimated Rp 600,000.
"The materials, which are set in the form of pyramid, are colored in either green, red or blue to find out the fish preference for their home," head of the technical service unit of Baruna Jaya Basri M. Ganie said.
"The artificial coral reefs are mostly made of concrete to allow them to last for 20 years. If we use natural materials such as limestone, it will only last for three to four years," Basri said.
The ministry, in cooperation with the Agency for Assessment and Application of Technology (BPPT) and the Navy, will also develop a national-scale mapping of the artificial coral reefs.
Experts from the Navy and BPPT have introduced the Electronic Navigational Chart (ENC), a system to create an electronic map which is later attached to electronic chart displays and information.
The technology allows accurate ship positioning, measures the speed and course of the ocean currents and improves ship safety as it can identify objects and devices.
"We have to identify the flow of water currents, the sea depth, salinity and other hydrological factors before placing the artificial coral reefs. If it's too deep, sunlight cannot reach it and no fish will stay. Usually we can see the result in three to four months," Basri said.
An assembled artificial coral reef commonly attracts hundreds of fishes, such as kakap, kerapu and stingray .
One cubic meter of artificial coral reef hosts between eight to 18 kilograms of fish, and it could develop up to 10 centimeters within a year, explained Hartanta Tarigan, director of Marine Technology of the Ministry of Marine Affairs and Fisheries.
Sarwono also called on local fishermen and members of Kepulauan Seribu community to protect the sites of the reef plantations as they are sources of income.
"We plan to develop fishing sites by planting as many artificial coral reefs as possible in Kepulauan Seribu area so the emerging sand zone can be preserved and the reefs will grow for at least two or three years," Sarwono told fishermen from Pulau Kelapa and Pulau Harapan on board the research vessel.
The minister asked the fishermen to stop the use of explosives in fishing.
During the session, the fishermen complained about the unclear implementation of regional autonomy Law No. 22/1998 especially on sea zone boundaries between provinces.
"We were sailing up north and suddenly we were told by other fishermen that we cannot fish there because they claimed the sea was theirs," H. Rojali of Harapan Island said.
Sarwono asserted that the sea belongs to every Indonesian. "All Indonesians can fish anywhere within the country's territory so long as they do not litter the sea," he said. (edt)