• Farmers remove thousands of dead fish from floating cages in the Lake Toba town of Haranggaol in May 2016. The fish died overnight from a lack of oxygen in the water.
  • The lake’s fishing industry lost more than 1,500 tons of Carp (Cyprinus carpio) and Tilapia (Oreochromis sp.) in the fish kill.
  • The mass fish kill took days to clean up. More than 100 Lake Toba fish farmers lost their entire stock, costing them thousands of dollars.

Photos: Binsar Bakkara

Photo Essay: How Pollution Is Devastating an Indonesian Lake
Uncontrolled fish farming, population growth, and logging have all taken a toll on Indonesia’s Lake Toba. Photographer Binsar Bakkara returns to his home region to chronicle the environmental destruction.
By Binsar Bakkara, 26th October 2016;

More than 1,500 tons of fish suddenly turned up dead in Indonesia’s largest lake earlier this year, a mass asphyxiation from a lack of oxygen in the water caused by high pollution levels. The event threatened the livelihoods of hundreds of fish farmers and the drinking water for thousands of people, and it shed light on the rapidly declining conditions in Lake Toba, the largest volcanic lake in the world.

Population growth, development, deforestation, and a booming caged fishing industry have severely degraded the lake’s water quality over the last two decades, scientists say. There are now 12,000 cages in the lake, each containing upwards of 10,000 fish, which is double or triple their capacities. Agricultural fertilizers, sewage, and most prominently, fish food have increased the levels of phosphorous in the lake three-fold since 2012, according to a government report. The lake, located in the northern part of Sumatra, is classified as either eutrophic or hyper-eutrophic, meaning it has excessive nutrients that can create dead zones with low oxygen levels.

Photographer Binsar Bakkara grew up on the shores of Lake Toba. While a kid in the 1980s and 1990s, “the clarity level of the water in the lake was very good,” Bakkara says. “Objects at 5-7 meters in depth could be seen clearly. But nowadays, it’s almost impossible to see any objects 2 meters deep because of the murky water.” When he heard news of the fish kill, Bakkara headed back to the lake to document the pollution.

Source: Yale Environment 360

Malaysia: Villagers urge Govt to review sample collection policies

19th September 2016;

Having twice lost valuable caged fish within 10 months to what appears to be river pollution, a community in Malaysia’s largest Ramsar site wants the government to review its policies on collecting water and other relevant samples.

One recommendation is for agencies entrusted with investigating such cases to relook at their standard operating procedures (SOP) as the delay in collecting samples does not translate into data that would be useful for mitigation or enforcement measures.

In July, Mumiang Village Development and Security Committee head, Mada Hussin had said 45 families lost four tonnes of caged fish such as Groupers (SubF. Epinephelinae) and Snappers (F. Lutjanidae) worth thousands of ringgit.

He said some caged fish were worth up to RM50 per kilogramme, a lucrative alternative economic activity for villagers who traditionally depended on catching fish but were no longer able to, due to dwindling stocks.

Mada said results of water and fish samples collected by the state fisheries department, environmental protection department and the federal Department of Environment were not shared with fishermen at Kampung Mumiang, following cases of suspected pollution last November and two months ago.

“It would be useful to hold a dialogue with the relevant agencies so that we can collaborate and look at the possibility of appointing water quality wardens from the community.

"We propose sampling stations be set up so that these community wardens can collect samples quickly. We also need to see how data collected by the community can be recognised.

"The relevant agencies must also frequently collect samples. The loss of aquatic biodiversity in the Lower Kinabatangan is an issue that impacts us and which is close to our hearts,” he said in a statement here today.

After the estimated RM100,000 losses last November, villagers received fish stocks from the government based on a subsidy mechanism and supplemented the supply by purchasing more.

“Now, most from this new stock have been destroyed. We only managed to salvage a few fish, the moment we noticed something amiss,” he said.

Mada believed the Malangking river, a tributary of the Kinabatangan was polluted with run-offs from an oil palm estate, especially when it rained heavily.

The waterway then turned light green, indicating algae-rich water which then impacted caged fish reared downstream.

Reacting to what happened in Mumiang, Ramsar Community Group Project lead facilitator Neville Yapp said a key focus of the project was related to water quality.

“We need the government to be supportive of this, including how data collected by the community can be taken as valid. We have identified the setting up of four water quality monitoring units in the near future under this project,” he said.

The Ramsar Community Group project falls under Forever Sabah, an ecology of partnerships that works to transform innovative visions for Sabah’s future into actionable solutions.

Mumiang is located in the Lower Kinabatangan Segama Wetlands, has no road access and is about an hour’s journey by speedboat from Sandakan town.

Mada said villagers had no choice but to continue rearing caged fish despite the risk of once again losing their fish in future.

“This has become a nightmare for us as there is not much else we can do here to earn a livelihood. We have families to raise and food to put on the table,” he said.

Source: Bernama

Malaysia: Villagers urge Govt to review sample collection policies

  1. A Maninjau fish farmer beholds a carpet of floating carcasses after the mass death last week.
  2. The dead fish are carried out of the lake in plastic bags.
  3. Dead fish in Lake Maninjau.
  4. Farmers use nets to clean the lake.

Photos: Vinolia

Indonesia: First Toba, now Maninjau: another mass fish death hits an Indonesian lake
It was only the latest fish kill in the volcanic Lake Maninjau, which scientists say is overburdened with too many fish farms.
By Vinolia, translated by Philip Jacobson, 9th September 2016;

  • Three thousand tons of farmed fish are thought to have perished in Lake Maninjau, the largest lake in Indonesia’s West Sumatra province.
  • The die-off follows a similar incident that occurred in Lake Toba, North Sumatra, in May.
  • As in Toba, scientists say there are too many fish farms in Lake Maninjau, exacerbating the natural factors that may have killed the fish.

Another mass fish death has hit Indonesia’s main western island of Sumatra.

Four months after millions of Carp (Cyprinus carpio) and Tilapia (Oreochromis sp.) died suddenly in Lake Toba, the archipelagic country’s biggest lake, a similar incident has occurred in Lake Maninjau nearby.

The latter event is thought to have been twice as deadly. Where in May, 1,500 tons of fish rose lifeless to the surface of Lake Toba, fish farmers in Maninjau said that an estimated 3,000 tons appeared to have perished there on August 31 — and that the losses were financially ruinous.

The Maninjau die-off was also greater in scope. Where in Toba, the fish kill was limited to the floating cages of Haranggaol village, where locals had packed a sheltered bay with vast rows of steel-framed net pens, the Maninjau incident affected several villages around the lake. Toba is 11 times the size of Maninjau and 19 times the size of Manhattan.

The fish in Maninjau appear to have been either poisoned by hydrogen sulfide gas from hydrothermal vents on the lake floor or asphyxiated by a sudden depletion of oxygen in the water. This may have been brought on by an inversion of the lake’s water layers due to strong winds or rains — “extreme weather,” as local officials and fish farmers termed it.

But these natural phenomena are exacerbated by human activity, said environmental geologist Ade Edward Darwin. The first problem is that there are too many fish farms. The lake’s carrying capacity for aquaculture is 6,000 cages, according to the Indonesian Institute of Sciences (LIPI), a government-funded thinktank. At present, 17,000 cages now lie suspended in Maninjau’s waters. Uneaten fish feed and feces from the net pens fuel a process called eutrophication, in which the water becomes excessively rich in nutrients. This nutrient loading can induce oxygen-devouring algal blooms that suffocate fish, as is thought to have happened in Toba in May.

An added complication in the volcanic Lake Maninjau is that sulfur from hydrothermal vents can morph into hydrogen sulfide which poisons fish. Sulfur can also trigger the release of phosphorus from fish-feeding sediments in the lake’s bottom, fueling the eutrophication cycle.

Fish kills are a regular occurrence in Lake Maninjau. In 2009, 7,000 tons of fish turned up dead in the lake. Another major incident happened in 2014. Darwin, the environmental geologist, said the die-offs had been growing in frequency as fish farming expanded. In 2001, a LIPI team visited the lake at the request of the provincial governor and recommended a reduction in the number of cages on the lake. “This could not be implemented by the district government,” Darwin told Mongabay.

When Mongabay visited Maninjau after the latest fish kill, a foul odor hung over the lake. Masses of flies hovered above the stinking pens. The rotting carcasses had begun to mar the water quality. A team from the Agam district fisheries agency was helping residents clean up the lake, using vans and excavators to transport the dead fish. The carcasses were buried in empty fields on the lake’s edge.

Eriandi, a local aquafarmer, said he lost 50 tons of fish and put his losses at nearly 1 billion rupiah ($76,000). “If one kilogram of fish costs 19,000 rupiah [$1.44], one ton of dead fish means a loss of 19 million rupiah,” he said. “If 1,000 tons, that’s 19 billion rupiah [$14.4 million].”

Many of the fish farms are backed by entrepreneurs from outside the area, with farmers going in debt to fund their operations, said Ermanto, head of the Agam district fisheries agency.

“It’s difficult to get them to change their ways because they have multiplied their debts and they want to keep farming so that the debt is paid off,” Ermanto told Mongabay.

Another problem is that farmers tend to use fish feed that sinks instead of the more expensive floating kind.

“For every 10 kilograms of feed dropped into the water, only 6 kilograms at most are absorbed. The remainder accumulates in the lake,” Ermanto said.

Source: Mongabay

  1. Dead fish are seen around Water Hyacinth (Eichhornia crassipes) in Haranggaol. The plants are a sign of excess nutrients in the water system.
    Photo: Aria Danaparamita
  2. Dead fish in one of the Haranggaol’s floating net cages in May.
    Photo: Ayat S. Karokaro/Mongabay

Indonesia: Why did millions of fish turn up dead in Indonesia’s giant Lake Toba?
A village of aquafarmers grapples with the aftermath of a mass fish death that nearly killed the local economy. Is it too late to prevent a repeat of the catastrophe from occurring?
By Aria Danaparamita, 30th August 2016;

  • In May, millions of fish died suddenly in the Haranggaol Bay of Lake Toba, Indonesia’s largest lake. Scientists chalked it up to a sudden depletion of oxygen in the water, the result of a buildup of pollutants in the lake, unfavorable weather conditions and unsustainable practices by local aquafarmers.
  • The local economy was badly shaken by the incident. Most residents of Haranggaol village rely on the fish farms as their only dependable source of income. Many villagers have had to go into debt to keep their businesses from collapsing.
  • Haranggaol residents have since tried to modify their practices to prevent another die-off, but without the resources and know-how of the lake’s corporate aquafarmers, they have had a difficult time.
  • Meanwhile, the government has big plans for Lake Toba as a tourist destination along the lines of a “Monaco of Asia” — one that might not include the unsightly fish farms.

On the morning of May 4, the fish farmers of Haranggaol were waking up to feed the Tilapia (Oreochromis sp.) and Carp (Cyprinus carpio) they raise in floating cages here on Indonesia’s Lake Toba. But when they got to the shore, the lake was gleaming white with fish carcasses.

“We were going to feed them, but the fish already died,” 39-year-old Mariando Nainggulan told Mongabay one recent evening in the village, home to 3,200 people.

Mariando, one of Haranggaol’s biggest aquafarmers, said he lost over 1 billion rupiah ($75,000) and had to borrow that amount from a bank to keep his business afloat. “It was sudden,” he said. “Of course I was sad. And of course I was confused.”

An estimated 1,500 tons of Tilapia and Carp perished in the first mass fish death to hit Toba, Indonesia’s largest lake, since 2004, when its Carp stock was demolished by the koi herpes virus.

This time, researchers pinned the blame on a depletion of oxygen in the water, brought on primarily by an excess of sewage, detergents, fertilizer — and fish feed. Met with overcrowded fish cages and unfavorable weather, the conditions became fatal.

It wasn’t the country’s first mass fish asphyxiation — notable incidents have occurred in West Sumatra’s Lake Maninjau and in the reservoirs of West Java — but it was the first time it happened in Lake Toba, according to a government agency that analyzed the Haranggaol incident.

Scientists have long warned that pollution in the lake is reaching untenable levels — and the Haranggaol fish kill may be the canary in the coal mine.

Surrounded by scenic mountains in North Sumatra province, Lake Toba was once a booming tourist destination. Formed by a volcanic caldera, the lake drew domestic and foreign visitors with its clear water.

But in the last two decades, tourism has slowed to a trickle, and even locals say that water in parts of the lake is no longer fit for drinking or swimming.

A damaged lake

In 2014, Bogor Agricultural University researchers classified the lake as eutrophic, meaning it had become excessively rich in nutrients like nitrogen and phosphorus — and prone to oxygen-devouring algal blooms. The Environment and Forestry Ministry’s inquiry into the May fish kill found that the lake’s phosphorus content had tripled since 2012.

The nutrient loading was worst near the floating cages, where large amounts of fish feed containing phosphorus, an essential element for fish growth, are daily dropped into the lake.

“Aquaculture shouldn’t be solely blamed for lake pollution,” Josh Oakley, an environmental specialist who studied the lake’s carrying capacity for aquaculture production, told Mongabay. Pollutants come from a variety of sources, such as agricultural runoff and sewage from houses and hotels.

Still, “The uncontrolled rising number of floating cages has caused grave environmental problems,” the Indonesian Institute of Sciences (LIPI) concluded in a report about the fish kill. “The number keeps rising, and is thought to have far exceeded the ecosystem’s carrying capacity.”

The 1,130-square-kilometer Lake Toba produces an estimated 76,000 metric tons of aquaculture products a year, much of it from local farmers. Two companies — Swiss-owned PT Aquafarm Nusantara and PT Suri Tani Pemuka, an arm of the Singapore-listed Japfa Group — also cultivate Tilapia on the lake and export fillets internationally, including to the U.S. and Europe.

PT Aquafarm — responsible for 40,000 tons of production in 2015 — has come under fire for introducing waste into the lake.

Haranggaol, the lake’s second-largest source of farmed fish, has also been criticized for pollution. Where in 2005 the village had 854 floating pens, today there are over 6,000. But that explosion, while a boon to the local economy, has come at a cost.

Sitting on an inlet ringed by steep hills on the lake’s northeastern edge, Haranggaol Bay is dominated by vast rows of steel-framed net cages across its 3-square-kilometer surface.

The bay’s small size and relatively calm waters means it particularly struggles to absorb all the effluents it receives. In a paper for the University of Rhode Island, Oakley determined its phosphorus concentration to be an average total of 110 milligrams per cubic meter, placing the bay “well beyond hyper-eutrophic status.”

The presence of domestic wastewater alone, he found, made it impossible for the bay to return to a preferred oligotrophic state, in which the water is low in nutrients and high in oxygen.

To achieve the next best thing — a mesotrophic condition — Haranggaol would need to drastically cut its fish production to only 20.12 tons per year, Oakley wrote. That’s a sharp cut from the estimated 27,000 tons it currently produces. Oakley notes that adopting more sustainable practices can help raise that production capacity. But even with the most optimal practices, Haranggaol would still only be able to farm 51.85 tons per year, he wrote.

Meanwhile, the environment ministry in Jakarta has called for a 44 percent cut in aquaculture production lakewide.

A military crackdown

The government has long struggled to curb the rise of unregulated community fish farms. A 2014 presidential edict stipulated that aquaculture would only be allowed in one district: Toba Samosir.

The campaign against fish farming ramped up in recent months after President Joko Widodo announced a plan to turn Toba — dubbed the “Monaco of Asia” — into a major tourist destination.

Local governments have wasted no time in carrying out the mandate. In late July, Simalungun district — which also covers Haranggaol — dispatched military and police officers to dismantle cages in Sualan village, about 70 kilometers south of Haranggaol.

After pleas from local fish farmers, the government agreed to postpone the eviction. Instead, the seven districts on the lake and the provincial government agreed on new zoning regulations, while asking the farmers to adhere to stricter environmental standards.

“Not zero — there are zones where they will be allowed so it is safe for the environment,” Mixnon Andreas Simamora, head of Simalungun’s development agency, told Mongabay.

Haranggaol is included as a fish farming zone. Still, news of the military operation in Sualan sent waves of panic to the village.

That, on top of the mass death, led the Haranggaol fish farmers to worry about what their future would look like.

A village of fish farmers

Haranggaol, a four-drive drive from Sumatra’s largest city, Medan, turned to fish farming in the 1980s after a virus wiped out its previous crops: onions and garlic.

“Haranggaol was threatened with starvation. Some wise people tried to farm fish,” said Hasudungan Siallagan, 45, head of the local fish farmers’ association.

Now, Hasudungan said, about 80 percent of the village relies on fish farming. “That includes laborers: net workers, delivery workers, they all live from the cages.”

For many of the villagers who don’t own land to farm, fish farming is currently their only dependable source of income. Many fund their businesses by taking out bank loans. Losing or severely reducing aquaculture would not only disrupt the families’ income — it would leave them under massive debt.

After the die-off, the farmers were forced to halt fish deliveries to local markets, and did not put in new crop for a month. Villagers rented trucks and machinery and banded together to bury the fish in a hillside mass grave.

In addition to the economic shock, the mass death forced Haranggaol’s fish farmers to reconsider the environmental impacts of their practices.

“The farmers don’t know good aquaculture techniques. We didn’t even know the carrying capacity per meter,” Hasudungan said, explaining that they mostly learned through trial and error.

After the fish kill, the villagers scrambled to find solutions to prevent another disaster.

“After the incident, we began to correct our practices,” Mariando said. “We rearranged the cages. Then we reduced the number of fish in the cages. We don’t put in 15,000 per cage anymore — just around 5,000 each cage. And the effect is visible: fish death has been significantly reduced.”

Yet to have any real impact on restoring the water quality, the farmers need to do a lot more than that.

‘Of course I’m worried’

It’s not just local farmers feeling the pressure to be more environmentally conscious. PT Suri Tani Pemuka, which also operates farming sites in Simalungun district, is experimenting with new cleaning technology.

The company began farming fish in the lake in 2012 and produced around 4,000 tons of fish in 2015.

Since last year, it has imported 12 “lift-up” cleaning systems from Norway to vacuum waste and dead fish from the net bottoms. The company also uses broadcaster machines that shoot out feed at a pre-programmed rate to reduce the amount of wasted pellets. And it’s working to reduce the phosphorus content of the Comfeed brand of pellets it produces, which is also sold to farmers.

“We do this because what is good for the environment is good for fish, and what is good for fish is good for the company,” Jenny Budiati, the company’s head of seafood processing, told Mongabay.

But although such innovations might be promising, local farmers who can’t afford Norwegian machinery are unlikely to replicate them in their own makeshift cages.

In his paper, Oakley outlined that certain practices could help increase Haranggaol’s carrying capacity. This includes placing the cages further offshore, where the water is deeper and currents can help maintain a healthier flow of oxygen and disperse waste. Farmers could also select feed that contains less phosphorus and ensure that fewer pellets are wasted.

In mid-August, PT Suri Tani Pemuka representatives held a workshop in Haranggaol on feeding practices and cage maintenance. But economic constraints are making it difficult for the Haranggaol farmers to make changes, even something as simple as switching to floating pellets with low phosphorus content since those cost more.

Since the mass death in May, the villagers have reorganized their previously haphazardly laid-out cages. Now the cages are arranged in lines, with some extending further offshore than before. That move alone cost the villagers the money they had saved to fix potholed roads in the village.

The Haranggaol farmers said they haven’t been told of any concrete plans from the government to help or incentivize local farmers to make their cages more sustainable.

“What does ‘environmentally friendly’ mean? What does that look like?” Hasudungan asked. “They have offered no solutions.”

Then again, improving fish farming is only one part of the solution. Haranggaol — and the lake region at large — must figure out better ways to treat pollutants from other sources.

Meanwhile, the question looms of whether Haranggaol’s pollution is so dire that large-scale fish farming simply can’t coexist with Lake Toba’s tourism dreams even with the most sustainable practices, as Oakley’s modelling suggests.

And while sustainability remains an elusive aim, Mariando says he has to think far more short-term: the two-month-old fish he’s currently growing in his nets.

“Of course I’m worried,” he said of continuing to farm in the wake of the die-off. “I’m waiting to harvest by the new year. Hopefully.”

Source: Mongabay

Photo: Ahmad Ridwan Nasution on Beritagar

Indonesia: Phosphorus pollutes Lake Toba, masses of fish dead
By Hans Nicholas Jong, 21st June 2016;

The government’s attempts to turn Lake Toba, the largest permanent body of water in Southeast Asia, into a first-rate tourist destination is facing a major hurdle, as a recent study found that pollution in the lake led to the deaths of millions of fish last month.

The study, conducted by the Environment and Forestry Ministry following the sudden death of millions of fish, revealed that the amount of phosphorus in the lake was 300 percent greater than it was in 2012.

Phosphorus is a common constituent of agricultural fertilizers, manure and organic waste in sewage and industrial effluent. It is an essential element for plant life, but when there is too much of it in water, it can speed up eutrophication (a reduction in dissolved oxygen in water bodies caused by an increase of mineral and organic nutrients) in rivers and lakes.

The mass death of fish in Lake Toba was down to an oxygen shortage, and led to losses of billions of rupiah. The oxygen shortage is believed to be caused by the alarmingly high amount of phosphorus in the water.

The ministry’s pollution director-general, Karliansyah, said that the toxic amount of phosphorus was caused by mismanagement of the lake.

“We have some recommendations. First, the sources of pollutants must be cut by 43 percent or 212,295 kilograms per year,” he said.

The pollutants originate from hotels, residences and agriculture, Karliansyah explained. “Detergents from households and hotels contribute the most. That’s why we’re asking domestic wastewater treatment plants owned by regional tap water companies to be optimized,” he said.

Besides that, the expansion of fish breeding in the lake has also worsened the water quality. The lake is home to 12,000 keramba (floating net cages) owned by local residents and entrepreneurs, but the local administration suggests that the number should be cut to a third of that.

Some cages, moreover, are overcrowded, containing 10,000 fish, despite their capacities being 3,000 — 5,000. The concomitant excessive use of fish fodder has increased the level of phosphorus in the water.

“We recommend that the number of fish in keramba be decreased by 44 percent,” said Karliansyah.

PT Aquafarm Nusantara, one of the biggest keramba fishery companies in Lake Toba, acknowledged the food pellets it had scattered in its keramba in Lake Toba had caused a decrease in water quality, but denied they had had a severe impact.

Long before last month’s fish deaths, the local Batak community had complained about environmental destruction and water pollution in Lake Toba, but the government has yet to outline any concrete actions to halt the damage.

Instead, it plans to promote tourism around Lake Toba, on Samosir island and in seven regencies that share the lake. Direct flights now operate between Soekarno-Hatta International Airport and Silangit Airport. A toll road is also to be built to shorten the travel time to reach the lake overland.

The government recently established the Lake Toba Authority to oversee licenses for the 500-hectare tourism area.

The environment ministry’s river and protected forest director-general, Hilman Nugroho, meanwhile said that the government was well aware of the problem, estimating that 16 percent of the lake was in critical condition.

Source: Jakarta Post

Photo: Julie Anne Jimena Celzo Facebook

Philippines: BFAR says heavy deposit of organic matters causing recurring fishkills in Pangasinan
25th May 2016;

Organic matters that had accumulated for years along the Caquipotan Channel, a body of water between the towns of Bolinao and Anda in Pangasinan, had made the area very susceptible always to fishkills, the Bureau of Fisheries and Aquatic Resources (BFAR) said.

Dr. Westly Rosario, chief of the BFAR’s National Integrated Fisheries Technology and Development Center (NIFTDC) based in Dagupan City, said the heavy deposit of organic matters in the bottom of the water was spawned by unsustainable aquaculture activities in the area for years.

At one area of the channel, the deposit of organic matter is measured at 32 centimeters thick and at another, especially the section from the steel bridge to Bolinao, it is more than one meter deep, Rosario said.

The Caquipotan Channel is the location of hundreds of floating fish cages and fish pens, all raising Milkfish (Chanos chanos) that need commercial fish for them to grow.

The commercial feeds unconsumed by the fish as well as the droppings of the fish in captivity are deposited in the bottom of the water to rot, causing pollution.

To date, the flushing out of water from north to south takes for sometime because of the heavy deposit of organic matters that are now decaying, Rosarfio said.

Rosario said that the biggest fishkill ever registered in the area happened in 2002, an incident which even caught world attention, prompting the Norway government to come to the aid of the Philippines by extending modern equipment and technical personnel who transferred improved fish farming technologies from their country to local technicians.

The equipment extended by Norway are now being used to help monitor water pollution in the aquaculture areas of Pangasinan as well as in other parts of the country, said Rosario.

He said following the advice of aquaculture experts after the 2002 record fishkill, the number of fish structures along the Caquipotan Channel was reduced a little bit but not substantially.

That was why in subsequent fishkills such as the one that happened last May 18, 19, 20 this year, aggravated by the occurrence of neap tide, fish losses were not as big anymore as the one registered in 2002.

Nevertheless, Rosario believes that the threat of further fishkill along the Caquipotan Channel will continue if fish farmers will not heed his call for moratorium of aquaculture activities there as well as the removal of heavy organic matter deposits.

Rosario maintained that because of years of overused, the Caquipotan Channel cannot accommodate anymore extensive aquaculture activities and must be allowed to rest for a while.

He repeated his earlier suggestion for the transfer of the fish cages in any feasible area in the Lingayen Gulf or in mid sea which is being done successfully in Norway that is now one of the biggest exporters of Salmon (Salmo salar).

Rosario also suggested that oyster props, beds and sticks be installed to replace fish cages along the Caquipotan Channel as Oysters (F. Ostreidae) and Mussels (F. Mytilidae), which have high commercial value both locally and abroad, can help clean the channel of organic matters.

Source: Northbound Philippines News Online

  • A carpet of dead fish in one of the floating net cages in Lake Toba.
  • Masses of dead fish are hauled away in plastic bags.

Photos: Ayat S Karokaro/Mongabay, Mongabay-Indonesia

Indonesia: Millions of fish die suddenly in Indonesia’s giant Lake Toba
Cause of death: not yet clear.
By Ayat S. Karokaro, 11th May 2016;

  • Government researchers are analyzing samples from the lake and should have a prognosis soon.
  • Hundreds of local volunteers have set about clearing the water of fish carcasses, which they fear will harm the ecosystem if left to fester for long.
  • The die-off means huge losses for local farmers.

When the sun rose over Indonesia’s giant Lake Toba on Wednesday last week, fish farmers saw that death in the night had visited their floating cages, and taken everything.

By Friday, millions of Carp (Common Carp) (Cyprinus carpio) and Tilapia (Nile Tilapia) (Oreochromis niloticus) had risen lifeless to the surface — ruinous losses for the aquafarmers.

The cause of death is not yet confirmed: government researchers are still analyzing samples from the lake. But early signs point to a precipitous drop in the water’s supply of dissolved oxygen, the suspected result of both natural and manmade causes.

One cage owner said that a week before the die-off began, the fish in their crowded cages appeared increasingly limp, and could be seen gasping to the surface for air.

Now, hundreds of volunteers are using heavy equipment and plastic bags to haul the stinking carcasses onto land. A giant hole has been prepared for their burial.

Lake Toba occupies the vast caldera of an ancient supervolcano whose eruption some 75,000 years ago ranks as one of the most violent events in geological history.

Volcanic activity is not thought to have triggered the fish deaths, though.

Krismono, a professor who works for the government, pointed to unfavorable weather. A lack of sun had shortcircuited oxygen production in the lake’s turbid depths, he said. It was possible that a mass of the depleted water had set off the catastrophe by rising to the top.

Overstuffed cages exacerbated the situation. “Cages should only have 3,000-5,000 fish, but these cages had 10,000 fish,” Krismono said.

Locals had also complained about water pollution, with some blaming aquaculture companies for contaminating the lake with uneaten food pellets and fish waste.

But the cages in Haranggaol, one of North Sumatra province’s biggest fish producing areas, are owned by individual small farmers.

“We can go bankrupt because of this,” said Hasudungan, a local aquafarmer.

Source: Mongabay