Can a wild fishery be bred? Indonesia's plan to restock its oceans
Melati Kaye
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Baby green sea turtles tussle over a scrap of frozen sardine at Bolong's Turtle Sanctuary in Lombok, Indonesia. The turtles will eventually be released to augment local turtle populations. Photo credit: Melati Kaye.
Abdul "Bolong" Hanan had a baby turtle in one hand and a toothbrush in the other. He scrubbed the squirming two-month-old vigorously before plopping it back into one of the shaded tile pools at his self-designated
turtle sanctuary on the southeast end of Gili Meno island off Lombok, Indonesia. Too much algae on a baby turtle's back makes it susceptible to bacterial infection, he explained.
The greenback held still for a moment, its flippers in a tight, surprised tuck. Then it relaxed and paddled among the 400 other baby green sea turtles (
Chelonia mydas) Bolong sheltered.
It was mealtime. The turtles skirmished for frozen sardine bits.
Bolong does not have a degree in conservation management. He has never even studied biology. But he built Bolong's Turtle Sanctuary himself and has successfully reared and released over 1,000 eight-month-old turtles into local waters since 2008. Bolong, his wife, and daughter gather eggs from turtle nests dug too close to beachfront hotel bungalows and other developments, then personally rear each turtle from egg to seaworthy juvenile. They claim that between 90 and 100 percent of the eggs they rescue hatch.
Many locals agree that there are now more turtles in local waters than there were in the 1990s. The abundance has even emboldened tourists to tell dive operators, "no turtle, no money" — as in, if they don't see a turtle during a dive, they won't pay for their trip.
Abdul "Bolong" Hanan scrubs algae off a baby green sea turtle to prevent bacterial infection. Photo credit: Melati Kaye.
Now the Indonesian government is trying to replicate Bolong's success on a national scale. But unlike Bolong's method of increasing the survival rate of a local population, the government will transplant animals. They may bring in animals from elsewhere when local numbers of a native species are low. Or they may introduce hybrids bred from outside species.
At a press conference in March, Indonesian fishery minister Susi Pudjiastuti said she plans to restock national oceans, starting with spiny lobster (
Panulirus homarus). "Aquaculture is so much work, why don't we just put fish in the oceans and harvest them?" she asked.
Details on the national plan are sparse, however. It is unclear, for instance, how many species the government plans to restock, in what areas of the country, or exactly how it intends to source the animals it will release.
Regional governments have run one-off restocking initiatives to enhance their offshore coral reefs by introducing hybrid fish species. In April, local government officials in Buleleng, Bali released a few thousand non-native hybrid groupers reared from Thai and Bruneian stocks. When mongabay.com asked about follow-up monitoring work to evaluate the success of the restocking, the officials admitted to not having a plan.
But examples from abroad suggest that restocking isn't as simple as dropping new animals into an existing ecosystem. Many restocking initiatives have failed, and not for lack of trying.
Mainland China undertook an extensive and expensive restocking initiative for large yellow croaker (
Larimichthys crocea) from the 1980s to the mid-2000s. But it failed to revive what was once one of the three biggest commercial fisheries in mainland China, which had succumbed to overfishing.
Despite additional boosts from two decades of seasonal closures and gear restrictions, plus $200,000 or more spent annually on restocking from 1999 to 2005, wild croaker stocks failed to recover, according to a
paper by University of Hong Kong researchers Min Liu and Yvonne Sadovy de Mitcheson. Moreover, their average age and size of sexual maturation declined over time, an indication of overexploitation and inbreeding The sums spent on restocking would have been better spent on managing the remaining wild stocks and enforcing fishing regulations, Liu and de Mitcheson concluded.
Even proponents of restocking say that the technique must be paired with ecosystem restoration.
A spiny lobster, photographed in Central Java. The species is targeted for restocking under an Indonesian government plan. Photo credit: Melati Kaye.
Japan — the country that consumes more fish than any other — has a national hatchery program that releases 80 different species of marine fish, crustaceans, and mollusks. But even there, researchers concluded that restocking "augments" wild production but "has limits depending on the carrying capacity of the environment," according to
a presentation by fisheries scientist Katsuyuki Hamasaki of the Tokyo University of Marine Science and Technology. In other words, habitat restoration is necessary for restocking to work.
Hamasaki also suggested removing predators, as well as follow-up research to determine how cost-effective an initiative is in increasing local catches or restoring local populations.
In 2006, Hamasaki co-authored a
review of the national stock enhancement program for kuruma prawns (
Penaeus japonicus) that Japan has had underway since 1964. He found that the number of predators and quality of the habitat determined the survival of hatchery-bred prawns sourced from other populations. The paper notes that "hatchery releases have not succeeded in augmenting total production of this species."
His co-author and university colleague, Shuichi Kitada, penned a
review of the national finfish stock enhancement program in which he analyzed the ecological impact and economics of restocking. Kitada found that hatchery-bred fish sourced from other populations didn't mate with local fish enough to increase regional stocks significantly. Instead, releases just meant greater landings locally, and therefore a more financially padded fishing community.
Pro- and anti-restocking researchers alike recommend small releases of marine animals at many sites as opposed to massive dumps at only a few. Small releases are less likely to stress local populations and ecosystems, and they are easier to monitor. Bulong's sea turtle releases and the ministry's release of 450 egg-bearing mud crabs (
Scylla serrata) near Bali airport in April both take that advice to heart.
But that's certainly not how all Indonesian restocking programs operate. The thousands of groupers released in Bali in April and the lack of any plan to monitor or assess their success make that much clear. When contacted by mongabay.com, the Indonesian national fishery ministry's Directorate of Research and Development, which is in charge of the lobster restocking initiative, likewise offered no specific plans for follow-up.
But even such small-scale projects as Bolong's turtle hatchery warrant follow-up research, if for no other reason than to settle a local debate about whether there are now "too many" turtles in the Gili islands.
One veteran Gili dive operator lamented how on any dive, you could now see 6 to 10 green sea turtles. "When the turtles are on the coral," Dray van Beeck told mongabay.com, "how can I tell my dive group to be careful about what they step on or touch?"
But Bolong countered that it isn't the turtles that are destroying the coral. "Before [Gili Meno] had dive operations… Before people started visiting, before there were people eating turtle eggs, there were lots of turtles," he said.
Judging from the situation on Gili Meno, another necessary ingredient for restocking initiatives is local buy-in.
Abdul "Bolong" Hanan feeds baby green sea turtles at his turtle sanctuary in Lombok, Indonesia. His small project has helped increase the local population of the species. Photo credit: Melati Kaye.
A five-minute walk south from Bolong's Turtle Sanctuary is a cement statue of a green turtle surrounded by a ten-foot-wide cement sandbox. This is the remnant of a government-commissioned turtle egg-laying ground. Turtles did lay their eggs there, but island residents dug them up to eat. Boiled turtle eggs are a traditional delicacy.
Bolong set up a fenced sand pit next to his roofed sanctuary. Here he buries the eggs he rescues from poorly placed nests. He sleeps nights at the sanctuary in order to keep close watch over the sand pit.
"People initially thought I was crazy to save turtles. I lose money on them but I think about my children's children," he explained when asked about his dedication. "I want them to see turtles."
Citations:
- Liu, M. and De Mitcheson, Y. S. Profile of a fishery collapse: why mariculture failed to save the large yellow croaker. Fish and Fisheries, 9: 219–242 (2008).
- Hamasaki, K. and Kitada, S. A review of kumura prawn Penaeus japonicus stock enhancement in Japan. Fisheries Research. 80, 80–9 (2006).
- Kitada S. and Kishino H. Lessons learned from Japanese finfish stock enhancement programs. Fisheries Research 80: 101–112 (2006).
Can a wild fishery be bred? Indonesia's plan to restock its oceans
