- A new study proposes establishing a marine protected area in Indonesia’s Java Sea-Makassar Strait region, one of the top fishing grounds in the country.
- The study found that much of the commercially valuable snapper and grouper species caught in these shallow waters are juveniles, which compromises the sustainability of the species’ populations and of the $500 million fishery itself.
- Another expert says imposing an MPA in this key fishing area would be a bureaucratic challenge, and instead suggests introducing an annual close season, similar to the one for yellowfin tuna in Indonesia’s Banda Sea.
- The study authors have also called for a change in consumer behavior, noting that the desire for snappers that fit on a plate is what drives the fishing of juveniles.
Indonesia’s snapper and grouper fisheries, together called the “deep-slope demersal fishery,” is one of the country’s most valuable fisheries, worth $500 million. It encompasses more than a hundred fish species, including white snapper (Pristipomoides typus), areolate grouper (Epinephelus areolatus), and a species of red snapper called the saddletail snapper (Lutjanus malabaricus).
Adult snapper and grouper live at least 50 meters (164 feet) below the ocean surface, and sometimes hundreds of meters, depending on the species, giving the deep-slope demersal fishery its name. Juvenile fish behave differently and tend to congregate in shallower seas than the adults. For example, saddletail snapper inhabit waters less than 10 m (33 ft) deep when they are young, and shift to much deeper waters, at least 140 m (460 ft), as adults.
Protecting immature fish is key to keeping any fishery sustainable in the long term. Catching juvenile fish before they are mature not only removes them from the population, but all of their future offspring as well. This can cause long-term population declines. Unfortunately for snapper and grouper, smaller immature fish are in demand because they fit neatly on a plate — which retailers and consumers love. But currently, the deep-slope demersal fishery is managed based only on the total numbers or weight of fish each vessel is allowed to catch. There is no monitoring of the size of fish caught.
New research published in the journal Conservation Science and Practice makes the case that the establishment of a marine protected area (MPA) could be an effective way to improve the management of the deep-slope demersal fishery. The study pinpoints the Java Sea-Makassar Strait region, where a large proportion of juvenile fish are hauled in, as a priority area for protection.
The Indonesian government had pledged to establish 200,000 square kilometers (77,200 square miles) of marine area for protection by 2020; as of January 2021, it was 9,600 km2 (3,700 mi2) short of that goal. Most MPAs in Indonesia are designed to protect coastal areas and the high-biodiversity coral reefs the country is known for. Establishing an MPA specifically to conserve the deep-slope demersal fishery is an unorthodox approach, but the researchers, led by Elle Wibisono, currently a Knauss Marine Policy Fellow at the U.S. Senate, argue that it could be a win-win for nature and the fishers that depend on it.
Wibisono and her colleagues gathered data on the species, numbers, and sizes of the fish caught by fishers on 384 vessels across Indonesia through a partnership with The Nature Conservancy. Boat captains were paid a small monthly stipend in exchange for their participation in the project, which asked fishers to photograph each fish on a flat board with a measuring scale. GPS trackers were also installed on the boats. This enabled the researchers to track how many immature juvenile fish were being caught and where.
With this information, the researchers identified several “hotspots” for immature fishing, which they defined as areas where the fishers’ catches included more than 75% immature fish. One hotspot they identified is the Java Sea-Makassar Strait region.
“The models corroborated what we already suspected,” Wibisono said. Waters in the Java Sea-Makassar Strait are relatively shallow, which juvenile snapper and grouper prefer, and the area is an important commercial and fishing zone. The next step toward determining how effective an MPA in the region would be, and where exactly it should be established, is to gather more detailed habitat and seafloor data. This information would allow researchers to “pinpoint specifically where within the Java Sea region … would be the most beneficial, and where the juvenile fish are, because the habitat data we used was not the highest resolution,” Wibisono said.
Fisheries management expert Abdul Halim, who was not involved in the research, said it’s an intriguing idea to protect the deep-slope demersal fishery through Indonesia’s MPA system. He agreed the approach could establish a monitoring system for the size of fishes being caught.
But, he added, it could be a difficult path. “Natural resource governance in Indonesia is a little bit unique in that the living natural resources in the ocean are under the Ministry of Maritime Affairs and Fisheries [MMAF]. But fisheries management and conservation areas are under two different subdivisions,” he said. Bridging the gap between these two parts of the MMAF and reconciling government regulations to manage fishing grounds as a conservation area could be a bureaucratic and legal challenge.
Halim suggested another option to ease fishing pressure on juvenile snapper and grouper in the Java Sea-Makassar Strait region. In 2015, the ministry decided to close a 130,000-km2 (50,200-mi2) swath of the Banda Sea, an important yellowfin tuna spawning ground, for three months per year after declaring the highly valuable fishery fully exploited.
“That could be a model” for managing the deep-slope demersal fishery, Halim said, if it was well-enforced. Given the potential challenges in creating an MPA to protect the fishery, “Looking at some other options, as well, is worth it to address the problem of immature fish capture.”
Regardless of which option the Indonesian government and other stakeholders ultimately choose to manage the snapper and grouper fisheries, securing the long-term sustainability of the industry will take time. The answer in the meantime, Wibisono said, is to find a practical way to differentiate among the individual snapper and grouper species that fishers are catching, because each has different sustainability levels and sizes to maturity.
Altering consumer behavior around seafood consumption could also help: “Most of the time [the fish] are caught when they are juveniles so they fit on a plate,” Wibisono said. “A lot of the drive on what fish species are caught is based on consumer preference…. [for example] there’s a lot of red snappers and we should be demanding for clearer naming on seafood products so that we know exactly what we are buying.”
Wibisono, E., Puggioni, G., Firmana, E., & Humphries, A. (2021). Identifying hotspots for spatial management of the Indonesian deep‐slope demersal fishery. Conservation Science and Practice. doi:10.1111/csp2.356
Wibisono, E., Mous, P., & Humphries, A. (2019). Using a collaborative data collection method to update life-history values for snapper and grouper in Indonesia’s deep-slope demersal fishery. bioRxiv. doi:10.1101/655571
Banner image: A fishing boat in Java Sea. Photo by B10m via Flickr (CC BY-NC-ND 2.0).
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