“This is for the future of our oceans,” Indonesian Fishery Minister Susi Pudjiastuti exclaimed when she announced minimum size limits for lobster and crab catches in January this year.
It was a commendable conservation initiative intended to boost crustacean stocks, particularly spiny lobsters (Panulirus penicillatus), an important export product. But the new regulation may inadvertently threaten the very species it aims to protect.
In Central Java one of Indonesia’s bigger source regions for lobster fishermen who once chased lobsters now target stingrays, showing how the unintended consequences of conservation-minded regulations could undermine their success. Stingrays stir up and oxygenate ocean floor sands, performing an essential ecosystem role by maintaining the habitat for the young of many commercially important species, including lobsters.
Even more troubling is that the main stingray species being targeted, the banded eagle ray (Aetomylaeus nichofii, known locally as ikan pari burung) is considered “vulnerable” to being endangered by the IUCN, while spiny lobsters are given “least concern” status.
In the beach town of Pantai Gesing on the Central Java’s turbulent southern coast, fishermen used to focus on netting lobsters for three months out of the year. Now that the new regulation forbids catching lobsters lighter than 300 grams (11 ounces) or with carapaces less than 8 centimeters (3 inches) wide, these fishermen, who once caught more lobsters than any other fishery in Central Java, have switched to fishing stingrays almost exclusively during lobster season.
Fishermen from Pantai Gesing set nets to catch lobsters because the sea is too deep around here to use traps. Lobsters caught in traps usually stay alive, so fishermen can keep only the ones above the size limit. But netted lobsters are often dead by the time they are brought up.
“We’re afraid to continue trying for lobster because our gear can’t differentiate by size,” Tugiman, the head of the local fishermen’s association, who like many Javanese only has one name, told mongabay.com. “Our equipment catches lobster big, small, egg-carrying, not. We can’t choose.”
The new crustacean regulation is pasted on the wall at the fish weighing station in Pantai Gesing, and one sentence is underlined: “Any fishermen caught with dead lobsters below the size limit will be fined.”
Below the posted regulation and next to the scale are four freezer bins filled with rays with three- to four-foot wingspans. Hendri, the pot-bellied leader of the weighing station team, popped the lid on one bin to show off the day’s catch.
“You see this raised part,” he said, pointing to the place where the stingray’s tail meets its body. “That’s what the exporters want. It looks like pearls once they polish it, makes for pretty wallets handicrafts.”
Stingrays weighing more than five kilograms (11 pounds) are sent to Jakarta, where their pelts are sold for handicrafts and their meat for consumption. Some of the skins are sent on to Taiwan, also for the handicraft market.
“In four hours flat, you can hook six stingrays to sell back at port,” Samingin, a fisherman from Pantai Gesing, told mongabay.com. “Each ray weighs between 10 and 15 kilograms [22 to 33 pounds] which translates to 200- to 300,000 rupiah [$15 to $23] a ray; and near a million rupiah [$77] a trip.”
That local fishermen are focusing their efforts on stingrays could have an effect on the larger ecosystem, Kathy Townsend, a specialist in Elasmobranchii, the family of sharks, skates, and rays, at the University of Queensland in Australia told mongabay.com. Lobsters are bottom feeders. But stingrays are mid-level predators.
“Rays allow things to grow,” Townsend explained. Rays live on sandy and muddy substrates. They feed on snails, small crabs, and worms, and in so doing they stir up sediment. If sediment sits too long, it becomes anoxic, or airless, and can kill mud-dwellers that form the base of the ecosystem, including lobsters and crabs. So, if enough rays are killed off, lobsters may end up suffocating and their populations could decline.
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