Scientists Say Indonesia Seagrass Meadows Degradation Threatens Food Security

Jakarta Globe 30 Sep 15;

Jakarta. A team of British scientists is launching a project this week that will investigate the condition of seagrass meadows off the coasts of Indonesia's South Sulawesi province – amid growing concerns over losses of the important marine ecosystem across the archipelago.

Richard Unsworth, a marine biologist from Britain's Swansea University and the leader of the project, said in an interview with the Jakarta Globe earlier this week that seagrass meadows were as important as mangrove forests and coral reefs were to marine life and food security.

Not to be confused with seaweeds or algae, seagrasses are a group of flowering plants that live in shallow sheltered areas along coastlines. Similar to grasses on land, seagrasses often form vast meadows underwater – thus the name seagrass meadows.

Unsworth says these meadows provide an important nursery ground for many species of commercial fish and sea invertebrates.

And yet, very little attention has been paid to the largely unknown ecosystem, even amid reports of disappearing and degraded seagrass meadows in many parts of the vast Indonesian archipelago.

A place to hide

“If you're a baby fish, and everything around you probably wants to eat you, you need somewhere to go and hide,” Unsworth began as he tried to explain the importance of seagrass meadows.

“The reef is full of a lot of really big fish that want to eat you. As a juvenile fish, the reef is a really dangerous place to be. But if you're in a seagrass meadow, it's full of dents, shoots, places where you as a small fish can hide."

“Also, in seagrass meadows there are a lot of small shrimps, really small shrimps, small mollusks, full of gastropods you can eat. So you've got shelter where you can hide from big predators, and you don't spend your energy swimming around looking for food. You have much higher chances of survival if you're a baby fish living in a seagrass meadow,” he added.

Previous reports suggest that over 600 species of fish in Southeast Asia utilize seagrass meadows at some point during their life. Many species of invertebrates – such as sea cucumbers, prawns and crabs – also live in seagrasses, which makes them very important to our food supply and security, Unsworth said.

Alarming losses

But while no study has been dedicated to examine the condition of seagrass meadows across Indonesia, reports of sightings – or lack thereof – by fishermen in many coastal areas in the archipelago suggest alarming losses of the important marine ecosystem.

Unsworth, who has been spending several years in Indonesia doing his seagrass projects, said in Jakarta Bay, for example, there used to be a lot of seagrass, but not anymore.

“That goes for many, many places,” the British scientist said, mentioning coastal areas in Sulawesi, Bali and Lombok.

“There are a lot of seagrasses I've seen around Indonesia in the years I've worked here that are looking unhealthy. And we know from some other works that have been done by LIPI [the Indonesian Institute of Sciences] and by some universities in Indonesia – that in many places seagrasses have disappeared [or] have been degraded,” he added.

Unsworth said it looked like only seagrasses in very remote locations in the country were in very healthy condition.

The Briton could not say exactly how many hectares of seagrass meadows have disappeared in Indonesia, only citing a rough estimate that there were some 30,000 square kilometers left now.

Around the world, seagrasses are estimated to be disappearing at the rate of one football field per hour, so this may also be the case in least-studied Southeast Asia, including Indonesia. But nobody knows for sure.

Seagrass and food security

Unsworth cited the findings of his team's previous study at Southeast Sulawesi's Wakatobi island – a popular diving spot known for its rich underwater life. The study found that seagrasses there provided a habitat for at least 70 percent of the fish species caught for consumption in the area.

The study was conducted between 2011 and 2014.

The project to be launched this week, meanwhile, is taking place off Selayar island and in the Spermonde archipelago in the neighboring province of South Sulawesi, and is targeted to last two or three years.

Unsworth said the new study was seeking to examine wider links between seagrass meadows and food security.

“There needs to be a lot more focus on this habitat because mangroves, seagrasses, coral reefs are all part of the connected sea scape, where if you lose one, it will impact the whole ecosystem,” he said.

“The loss, the damage of the marine environment is a very significant problem – because the world's population is increasing, Indonesia's population is increasing. And we need to feed people.”

Unsworth and his peers – including collaborators from Britain's Cardiff University and from Hasanuddin University in South Sulawesi's capital Makassar – wish to understand what causes the degradation and disappearance of seagrass meadows in Indonesia.

He said climate change was known to have long-term impacts on seagrasses, “but we need to understand the factors that are driving and disturbing seagrasses at a smaller scale. Because that's really important in terms of understanding how resilient they will be into the future.”

Unsworth and his team recently published a research article in an international journal called Marine Pollution Bulletin – which explains how seagrasses need to be made more resilient.

“And the ways to do that is to stop the small-scale disturbances that we know happen in seagrasses all around Southeast Asia and Indonesia,” he said, citing damaged mangrove forests and polluted rivers spilling out into the sea as among key factors.

The British scientist further added the newly-launched project in South Sulawesi was part of an ongoing regional study also taking place in the Philippines, Cambodia and Srilanka.

The project includes trainings and workshops for local fishermen, to teach them how to protect seagrass meadows in their areas – and not just the mangrove forests and coral reefs.

In Indonesia, Unsworth's team also collaborates with a Wakatobi-based environmental group, Forkani, to deliver the workshops.

To learn more about Richard Unsworth's work and his team's seagrass projects, visit http://www.projectseagrass.org/ and http://www.seagrass.org.uk/.