Home to giant catfish and stingrays, feeding over 60 million people, and with the largest abundance of freshwater fish in the world, the Mekong River, and its numerous tributaries, brings food, culture, and life to much of Southeast Asia. Despite this, little is known about the biodiversity and ecosystems of the Mekong, which is second only to the Amazon in terms of freshwater biodiversity. Meanwhile, the river is facing an existential crisis in the form of 77 proposed dams, while population growth, pollution, and development further imperil this understudied, but vast, ecosystem.
“More than 850 species have been described, and researchers estimate there could be over 1,200 species. As a comparison, the whole state of California has about 67 freshwater fishes,” Harmony Patricio, a conservation biologist and the conservation director at FISHBIO, told mongabay.com in a recent interview. “The Mekong is also the most productive freshwater system on the planet in terms of fish biomass. The estimated annual harvest is over 2.6 million metric tonnes per year, which represents about 18% of the total global inland fishery harvests. That’s almost 1/5 of all freshwater fish harvest across the world, found just in this one river basin.”
A new program by FISHBIO, headed by Patricio, is working to compile and disperse data on the freshwater fish across the region, including gathering information on harvesting. The Mekong Fish Network, as it’s called, hopes to draft baseline data, so that information can be compared over regions and time.
 Catfish in Lao PDR market from the Mekong. Photo courtesy of FISHBIO. |
“The main goal of the Mekong Fish Network is to help people working with fish in the different countries of the Mekong Basin to collaborate across national borders and share information so we can better understand what’s happening with Mekong fishes throughout the basin,” she says. “These fish migrate between six different countries: China, Myanmar, Lao PDR, Thailand, Cambodia and Vietnam. These countries all speak different languages and have different cultures and government structures, but the fish don’t abide by national borders.”
The data is so important, according to Patricio, because the Mekong River Basin plays a vital role of the many communities that live along it.
“The river means everything to the people living in the basin, especially in rural areas. It’s their source of life. More than 60 million people depend on the fish for food, which typically accounts for more than half of their animal protein. There’s not really a substitute for that. People also use the river for transportation, for their household water supply, and for growing rice and farming.”
However, the river is imperiled by a wide-range of global and local environmental impacts including climate change, pollution, agriculture, logging, the aquarium trade, urban development, and a rapidly rising human population. One of the most immediate threats, however, is the proposed construction of 77 dams on the river, including the controversial Xayaburi Dam, which Patricio says could interrupt the migration of the giant catfish. Considered the world’s biggest freshwater fish, the giant catfish is listed as Critically Endangered and has largely vanished in recent decades. Despite it’s incredible size, scientists still know little about the animal.
“Overall, the cumulative effect [of dam construction] will probably be a reduction in the number of migratory species and a shift in the species composition to favor species that do well in reservoirs,” says Patricio. “Right now, we know more than a third (38%) of the total Mekong fish harvest consists of migratory species. If the biomass of the reservoir species doesn’t scale up to replace the migratory species, we could see a decline in total harvest or productivity.”
She adds, however, that there are ways to mitigate the damage of the dams, such as building massive bypass channels around the dam. In addition, officials could look at other power-generation technologies that wouldn’t involve damming the river.
 Big catch from the Mekong. Photo courtesy of FISHBIO. |
“Some cool research is looking into building small turbines that are bolted to the riverbed, like free-standing barrels. Screens protect the fish from the turbines, and there is lots of space for fish to pass around,” she says. “People are also designing mesh grids with tiny turbines, maybe the size of a cube of ice. You put that on the substrate, and the little turbines combine to produce a fair amount of electricity, although they can’t generate the amount of electricity that the large dams can.”
Given the immense human and development pressures on the Mekong River Basin, it’s worth wondering how much of the river’s environments can be salvaged, and, if degradation occurs, how many people—dependent on the river for their livelihoods and even their cultural identities—will be harmed? Such questions, which are being asked across the developing world, point to a similar theme: development at what cost? Most countries have been snagged by the idea of development hook, line, and sinker, but their focus remains on big, industrial projects, rather than smarter, smaller, and more locally-driven development.
“It’s quite frustrating that there is a lot of money being poured into development in the Mekong, but it’s hard to get that same level of commitment for environmental research, monitoring, or conservation. In river basins like the Columbia, billions of dollars are spent every year to study, monitor and manage a few species, mostly salmon. Why is the Columbia more deserving of that research and attention than the Mekong?” Patricio asks, adding that it’s time the international community comes to see the Mekong as one of our most important ecosystems.
“The world needs to realize that the Mekong is like the Amazon rainforest. It’s a global resource of incredible diversity and productivity, and the rest of the world needs to support local governments like Laos so they aren’t so pressured to just develop without maintaining the balance of natural resources or aquatic diversity.”
Erin Loury also contributed to this interview.
AN INTERVIEW WITH HARMONY PATRICIO
Hamrony Patricio (center) taking fish samples in the Mekong River. Photo courtesy of FISHBIO.
Mongabay: What’s your background and how did you start working in the Mekong?
Harmony Patricio: I studied conservation biology because I’ve always been fascinated by the incredible biodiversity found in aquatic ecosystems. When something captures your passion like that, you just have to do what you can to help protect it. I first worked in Costa Rica and Nicaragua, directing research for the Rainforest Biodiversity Group. Then I went on to study the impacts of climate change on diversity, food security, and livelihoods in West Africa for the United Nations World Food Programme. The fisheries consulting group FISHBIO hired me in 2009 to develop an international conservation program for the company. I was initially planning to start the program in Latin America because I speak Spanish and I’m familiar with the species. However, shortly after starting my work with FISHBIO I attended the International Congress for Conservation Biology in Beijing, where so many people told me about the amazing fish diversity in the Mekong, how little is known about the lifecycles of most species, how important the fish are for the people living in the Mekong Basin, and how many big changes were on the horizon in Southeast Asia. So I had a feeling that the Mekong would be the next hotspot for fish conservation.
I knew it would be challenging because it was a new environment for me and I didn’t speak the languages. I decided we had to face these challenges head on, because FISHBIO’s primary goal for our international work is to share our technical expertise in the places where it’s most needed. I felt like the Mekong region, and Lao PDR in particular, had a high need for technical capacity building to support local scientists. So we decided to base our regional office in Vientiane.
THE AMAZING MEKONG
Mongabay: What makes the Mekong River special in terms of fish?
Sample fish taken from the Mekong. Photo courtesy of FISHBIO.
Harmony Patricio: It has the second largest number of fish species of any river on earth, only after the Amazon River. More than 850 species have been described, and researchers estimate there could be over 1200 species. As a comparison, the whole state of California has about 67 freshwater fishes. The Mekong is also the most productive freshwater system on the planet in terms of fish biomass. The estimated annual harvest is over 2.6 million metric tonnes per year, which represents about 18% of the total global inland fishery harvests (Link to source: http://www.worldfishcenter.org/resources/publications/mekong-fisheries-and-mainstream-dams-fisheries-sections). That’s almost 1/5 of all freshwater fish harvest across the world, found just in this one river basin. What’s also special is how important the fish are for the people. There are over 60 million people that depend on the fish for protein and income, and the economic value of the fisheries is as much as $3.8 billion US dollars per year on first sale. So the river’s fish are highly diverse, feed a lot of people, and are worth a lot of money. There are also some really unique and endemic species that you won’t find anywhere else on earth.
Mongabay: Will you tell us about a few standout species?
Harmony Patricio: One obvious standout is the Mekong giant catfish (Pangasianodon gigas) because it is on record as the world’s largest freshwater fish. It’s like the blue whale of freshwater. It can grow to up to 3 meters long (9.8 feet), and weigh 350 kilograms (770 pounds). The giant catfish migrates long distances between several different countries, and is primarily vegetarian, which is unique for such a large fish. Another standout species would be the giant freshwater stingray, which can grow up to 2.4 meters long (7.8 feet) and 5 meters wide (16.5 feet), and weigh up to 240 kilograms (530 pounds). It’s huge!
In addition to the stingray, there are other fishes you’d typically expect to find in the ocean, like electric eels and puffer fish. Some of the Pangasiid (a type of catfish) species are also really interesting. One, Pangasius krempfi, is believed to migrate to the ocean, and they have been seen along the coast of the South China Sea in Vietnam. They also migrate extensive distances, past Cambodia and over major waterfalls at the southern border of Lao, all the way up to northern Lao. The fact that they use both freshwater and saltwater and also migrate through the entire Lower Mekong Basin is pretty amazing.
Mongabay: How do local people depend on the river?
Fisherman navigating the river in Lao PDR. Photo courtesy of FISHBIO.
Harmony Patricio: The river means everything to the people living in the basin, especially in rural areas. It’s their source of life. More than 60 million people depend on the fish for food, which typically accounts for more than half of their animal protein. There’s not really a substitute for that. People also use the river for transportation, for their household water supply, and for growing rice and farming.
One unique thing about the Mekong is that it has the highest range of flows of any river on Earth. The difference in flows between the wet season and the dry season is immense. During the rainy season, the water levels rise and deposit a lot of nutrients and sediments along the banks. In the dry season, the water level goes down and people in rural areas have this really rich soil where they plant riverside gardens, which are an important source of vegetables like beans and corn. So in the dry season, maybe they can’t catch as many fish, but they have these riverside gardens that are really productive. The river also delivers huge amounts of sediment to the delta in Vietnam, which supports some of the world’s highest rice production and the nutrients in the sediment create a marine plume that contributes to high fish abundance in the ocean off the coast of the delta. Scientists are just now starting to understand the role of this marine plume for fish production.
Mongabay: What is the cultural significance of the Mekong River’s species?
Harmony Patricio: The Mekong giant catfish has a lot of cultural importance for the local people. There is a lot of tradition surrounding how the fish is harvested in the wild. Now the wild population of giant catfish has gotten so low that most countries have made it illegal to catch a giant catfish in the river. I’ve talked to older fishers in villages that historically harvested the giant catfish, and it’s really a sad thing for them that their children aren’t going to experience that part of their culture. It was a very communal experience with a lot of ceremony involved.
In some places, the whole community would get together for ceremonies and prayers. You need a lot of people to catch this fish; it’s really big and heavy! After a successful harvest of a big fish, people would often share the meat and have a big ceremony and celebration. This really important cultural tradition has disappeared now.
There is also a freshwater dolphin in the Mekong, the Irrawaddy dolphin, that has a lot of cultural significance. People really honor the dolphin, and there are many stories about dolphins helping drowning people or helping fishermen to catch fish. So they never kill the dolphins.
RESEARCH IN THE MEKONG BASIN
Mongabay: What do you hope to achieve with your new project: www.mekongfishnetwork.org?
Scientists sampling fish species: black catfish is an invasive species from the Amazon. Photo courtesy of FISHBIO.
Harmony Patricio: The main goal of the Mekong Fish Network is to help people working with fish in the different countries of the Mekong Basin to collaborate across national borders and share information so we can better understand what’s happening with Mekong fishes throughout the basin. These fish migrate between six different countries: China, Myanmar, Lao PDR, Thailand, Cambodia and Vietnam. These countries all speak different languages and have different cultures and government structures, but the fish don’t abide by national borders. They use different parts of the river basin for different parts of their life cycle, so sustainably managing or conserving these fishes requires international cooperation.
We also hope to develop and implement standardized fish sampling methods throughout the basin to build a long-term monitoring program that studies how these fish populations change over time. No basin-wide program like this currently exists, and we need it if we want to achieve more sustainable fisheries management, conserve some of these rare or migratory species that are on the brink of extinction, and sustain the river’s productivity that people rely on for food and income.
FISHBIO worked with the U.S. Geological Survey to convene a consultation workshop in Cambodia in 2012, which brought together fish researchers and mangers from across the basin to talk about pressing issues and what tools they need to better study and manage Mekong fish. The Mekong Fish Network was designed in response to their requests to provide tools and resources that can help build technical capacity and advance scientific study across borders.
Mongabay: Why has fish research and conservation been so challenging in this river?
Harmony Patricio: A lot of good research has been done in the region, but part of the challenge is sharing that research and information across institutions and national borders. You either have to translate everything, or everybody has to learn one language. The river also covers a huge geographic area that is incredibly diverse, both culturally and ecologically. The habitat changes dramatically from northern Laos to Cambodia to the Mekong Delta in Vietnam. The river in northern Laos is bounded by high mountains with deep, rocky gorges. In southern Laos there are huge waterfalls, and in Cambodia the river spreads out, gets more sandy and flat. Cambodia’s great lake, the Tonle Sap, is like a huge flood plain of fish rearing habitat. A lot of the delta is very developed, with many different channels. It’s challenging to conduct research in such a wide variety of habitat types.
Traditional fishing on the Mekong. Photo courtesy of FISHBIO.
You also have many different people involved in fishing—men, women, and children—at all different scales. People will fish for just 20 minutes for subsistence, just enough to get dinner for their family that night. Then there are big commercial operations in the Tonle Sap that pull in huge hauls. Trying to measure and research the harvest at these different scales is really challenging.
Conservation has been a challenge since there is so much we don’t know about the basic biology, life cycles, and ecology of the fishes. There needs to be more funding and more technical expertise made available to the region so this basic species information can be used to design conservation strategies. In a multinational region with migratory fish, conservation also has to work across borders. The fish move between different countries, so you really need the countries to agree to work together and conserve the fish at all the different stages of their life cycles.
There is also a real need to build technical capacity for research and conservation among local agencies and researchers, particularly in Laos and Cambodia. Even something really fundamental like data management is a challenge. People may not have trained IT staff or the skills to build a database, maybe they can’t afford to buy licensed software, their data could get corrupted, or it never gets analyzed if project funding ends. To address some of these issues, FISHBIO has worked with the U.S. Geological Survey to develop the Mekong Fish Network Data Bank, which is a free tool to help Mekong researchers store, manage, and share their data. (http://delta.usgs.gov/fm/data/fm_fish/Home.aspx)
Mongabay: What data are you hoping to collect regarding fish species in the river?
Harmony Patricio: We want to improve fish distribution data and identify important spawning locations and migration periods. We also want to improve fish population estimates. Right now, all the population estimates are based on catch statistics, which I think is a good proxy, but it doesn’t tell you about the fish that people aren’t catching. For example, the giant stingray is very rarely caught, and isn’t targeted at all for fishing. People currently aren’t going out there trying to figure out where the giant stingray spawns, how much habitat it needs, where it eats, how much it moves around. So we want to improve our knowledge of fish that aren’t targets for harvest.
One of the main things we want to do is track trends over time and see what happens to fish populations as we see changes in harvest pressure and environmental conditions. The first thing we need to know if we want to manage fisheries is if the populations are going up or down. Developing a set of standard data that we collect across the basin will allow us to compare fish data between locations and over time —that’s a really important goal of the Mekong Fish Network.
THE DAM SPREE AND OTHER THREATS TO THE MEKONG DELTA
Mongabay: What impact do you think the Xayaburi Dam would have on fish species in the Mekong River?
Fish market in Lao PDR: millions depend on the Mekong for food. Photo courtesy of FISHBIO.
Harmony Patricio: The strategic environmental assessment for mainstem dams that was commissioned by the Mekong River Commission suggests that mainstem dams like the Xayaburi could block the migrations of some rare or economically valuable species. It could alter the species composition to favor fish species better adapted to a reservoir environment. The fish that can withstand lower oxygen levels or higher temperatures and can survive in a reservoir will do better than fish that need the free-flowing river environment or that are highly migratory.
Also, no one knows for sure where the giant catfish spawns, but based on local ecological knowledge, people believe they spawn upstream of the Xayaburi Dam location. It would be a problem if the giant catfish can’t make it past the dam, but they’ve already stopped showing up to these traditional spawning grounds—they’ve already been affected by changes to the river. Maybe they will be able to spawn somewhere downstream of the dam. The dam could also trap sediment that is very important for maintaining downstream habitat in the Mekong Delta in Vietnam. Ultimately, the Xayaburi is likely to have some impacts on fish, but there are plans for many other dams as well.
Mongabay: While the Xayaburi Dam has received the most attention, there are actually 77 dams planned for the river over the next few decades. What could be the cumulative impact of these?
Harmony Patricio: The impact is really going to depend on the development scenario: whether all of those dams are built in the locations where they’re planned now, and how they’re built. There are many alternative scenarios that could reduce impacts on fish and still generate a substantial amount of electricity. Overall, the cumulative effect will probably be a reduction in the number of migratory species and a shift in the species composition to favor species that do well in reservoirs. Right now, we know more than a third (38%) of the total Mekong fish harvest consists of migratory species. If the biomass of the reservoir species doesn’t scale up to replace the migratory species, we could see a decline in total harvest or productivity.
Toothy fish in market in Vietnam. Photo courtesy of FISHBIO.
The sediment trapping could reduce the productivity of the marine fishery off the coast of the delta and the delta itself could suffer land loss from erosion, which might affect rice production. People also talk about how dams will change the river’s flow regime. Right now the Mekong has a very dynamic regime, extremely high flows in the rainy season, and very low flows in the dry season. This difference in flows is one reason why people think the river so productive. It causes the flooding of the Tonle Sap, creates floodplain habitat, and the potential for riverside gardens. A lot reservoirs and dams will reduce the variability of the flow regime. The dry season flows will be higher and the wet season flows might be a bit lower. There are a lot of questions about how this will affect the system.
Mongabay: Can any dams be considered fish-friendly?
Harmony Patricio: Well, it depends on what kind of fish you’re talking about! There are definitely ways to design dams to minimize their impacts on fish. You might have to sacrifice a bit of the power generation capacity, but maybe it will be worth the gain you get from maintaining fish populations. One strategy they’re looking at now for dams on the Mekong mainstem is building big bypass channels, basically creating a new river channel that goes around the dam. It’s obviously not as big and wide as the natural river, but it provides fish with a more natural riverine environment, rather than trying to build an elaborate fish ladder or elevator system over the dam itself. I think that approach is probably the most “fish-friendly.”
Fish passage is a challenge because there are more than 100 highly migratory fish species in the Mekong, ranging in size from less than 10 centimeters up to 300 centimeters. Obviously, their swimming and jumping capabilities are going to be really different. In addition, huge volumes of fish move at the same time in the Mekong, and it’s hard to engineer something that can accommodate such a huge quantity of fish to pass a dam.
There are also ways of generating hydropower without making big dams. Some cool research is looking into building small turbines that are bolted to the riverbed, like free-standing barrels. Screens protect the fish from the turbines, and there is lots of space for fish to pass around. People are also designing mesh grids with tiny turbines, maybe the size of a cube of ice. You put that on the substrate, and the little turbines combine to produce a fair amount of electricity, although they can’t generate the amount of electricity that the large dams can. I would say the most fish-friendly approach would be to use these small-scale, alternative technologies that maybe can’t produce as much power per facility, but you could spread lots of them out in places that aren’t essential for spawning or feeding.
Mongabay: Aside from dams, what are other threats to fish biodiversity on the river?
Large construction project on the Mekong in Lao PDR 2010. Photo courtesy of FISHBIO.
Harmony Patricio: Dams are just one piece; there are a lot of other changes happening in the system. Global climate change will affect precipitation and water temperatures in the region. There is industrial pollution, and logging causes increased sedimentation of the river. Mining causes mercury and other chemicals to leach into the river. The human population is growing very quickly in the region, and harvest pressure is increasing. As people get more money, the amount of food they consume per capita also goes up, so not only are there more people, but each individual is going to consume more. A lot of fish are collected for the aquarium trade and sold all over the world. Structural changes to the river, such as creating levees and dykes for flood control, are changing the habitat. Agricultural expansion causes competition for water, and contributes pollution from pesticides, fertilizers, and animal waste. And industrial expansion is leading to filling wetlands for urban development. So there are many environmental challenges facing fish in the Mekong.
Mongabay: What do you think the future holds for the Mekong?
Harmony Patricio: I think the important point is that it’s not too late for conservation. They’re at a turning point right now in the region. We can look back at hydropower development in places like California and see what things we would have done differently if we had known more about the fish biology and ecology, how we could have balanced fisheries with the use of the river for other purposes. The exciting thing about working in the Mekong is that all these decisions are begin made right now, so there’s still time to move forward in a more sustainable way. There are lessons to be learned from the rest of the world about how to maintain your aquatic resources while still developing your economy and producing the electricity that you need. Doing that will require bringing people from all the Mekong countries to work together and collect standard data to keep tabs on the fish to inform management and development. The Mekong Fish Network can play a big part in supporting this type of research.
It’s quite frustrating that there is a lot of money being poured into development in the Mekong, but it’s hard to get that same level of commitment for environmental research, monitoring, or conservation. In river basins like the Columbia, billions of dollars are spent every year to study, monitor and manage a few species, mostly salmon. Why is the Columbia more deserving of that research and attention than the Mekong? The world needs to realize that the Mekong is like the Amazon rainforest. It’s a global resource of incredible diversity and productivity, and the rest of the world needs to support local governments like Laos so they aren’t so pressured to just develop without maintaining the balance of natural resources or aquatic diversity. The local governments are trying to bring their people out of poverty and meet their development goals. The international community needs to take some responsibility and take action for this really unique and precious place, to care about it like we care about the Amazon. Even if you don’t live there, it’s important to know that places like it exist, that those species and diversity exist somewhere. Many people feel that way about the Amazon—I think we need to think that way about the Mekong too.
Tiny pufferfish (left) in hand. Photo courtesy of FISHBIO.
Fish trap in Lao PDR. Photo courtesy of FISHBIO.
Fishing along the increasingly urbanized Mekong. Photo courtesy of FISHBIO.
About FISHBIO
FISHBIO is a fisheries and environmental consulting company with offices in Chico and Oakdale, California, and Vientiane, Laos. The group is dedicated to advancing the research, monitoring, and conservation of fishes around the world. To support global conservation efforts, FISHBIO partners with international agencies, NGOs, and local communities to provide technical assistance and share expertise developed through years of experience with freshwater fish monitoring in California. FISHBIO has provided funding and resources for a number of conservation projects in the Mekong region, reflecting the company’s mission to improve the study and sustainable management of fishes. For more information, please visit www.fishbio.com.
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