Delta flows: The role Delta’s play in sustaining basin-scale fisheries in the Mekong and Irrawaddy rivers
In line with World Wildlife Day which is celebrated this year today under the theme ''Forests and livelihoods: Sustaining people and planet'', the basins of both the Mekong and Irrawaddy Rivers are complex social-ecological systems providing resources to support large, reliant local populations. Migratory fish species are a major resource provided by both rivers and an essential component of food security in delta and upstream areas. But fisheries are threatened by plans to fragment the rivers with the construction of dams and alter their flows to prioritize energy generation. This fragmentation cuts off critical migration pathways and flow alterations disrupt habitats required for different life stages of key fish species.
Investigating fish migration
It has been long suspected that many large upstream migrant fish in both systems possibly originate from the ocean. If this is true, planned future main stem dams will effectively destroy whole fish species by blocking access to critical habitat. It is not too late yet. If hard data on fish migration can be obtained now, there is a substantial opportunity to either alter the planning on such dams, and move them away from migratory routes, or at a minimum ensure they incorporate adequate fish migration facilities. Although fish migration has been a consideration in the Mekong over the last decade, fish migration work is still in its infancy in Myanmar.
The “Delta Flows” project aimed at gathering relevant information in relation to the key migratory species in the Mekong and Irrawaddy river basins to start a dialogue with government, and campaign for the importance of fish migration in infrastructure development. This project was led by National University of Laos in collaboration with the Research Institute for Aquaculture Vietnam, Can Tho University Vietnam, Yangon Technical University Myanmar, Ministry of Livestock, Fisheries and Rural Development Myanmar, Myanmar Institute for Integrated Development and Charles Sturt University Australia.
Building and strengthening local capacities
The first step of the project was to build and strengthen local capacity on delta fisheries in both basins, and to increase and expand the current state of knowledge and innovative technologies used to map migratory pathways. At the start of the project, very little information was shared or exchanged on between the Mekong and Irrawaddy river basins on fish migration and the potentially devastating impact of river infrastructure. To tackle this, a collaborative programme between Myanmar and Laos was initiated to foster knowledge exchange between the two countries, but also to communicate externally, early in the project.
Learning new skills
Together with researchers, authorities and communities from Myanmar, Laos, Cambodia, Vietnam, Thailand and Australia, the project team conducted training and fieldwork to obtain sample information on the most important subsistence, commercial and endangered fish species. From the information gathered, the key species identified were sampled, and using innovative technology, otolith microchemistry, the key migratory patterns of these fish have been analyzed and key migratory species were identified.
In both the Mekong and the Irrawaddy, a number of otoliths (earbones) had been collected from an important long-range migratory catfish species. These otoliths were analysed in two ways to test if these fish were migrating between the freshwater and the sea. This was the first time that fish otoliths were used as a mechanism to obtain information on fish migrations, across all three countries simultaneously. There were two types of equipment specific to this work (a) Laser ablation Mass spectrometry and (b) X-ray fluorescence using synchrotron science. The approach and techniques used were novel, innovative and cutting-edge and neither of these approaches had been used by the collaborating team before. As such, it was a significant challenge for the Australian team to build capacity across the three countries and to ensure the team worked on these collaboratively and successfully.
Confirmed suspicions
Results from the otoliths clearly show that fish have moved from the freshwater to the sea and back again, and this has far reaching implications for expanding tidal defence, irrigation and hydropower infrastructrure. Without consideration of these migration patterns, key commercial, livelihood and conservation status fish will be lost. Knowing this, what are the next steps? These crucial findings were shared with the relevant governmental authorities in charge of water control infrastructure plans, such as the Ayeyarwady Delta Plan and the Myanmar Agricultural Development Strategy.
Continued collaborations
The collaboration between the countries in the Delta Flows project has led to Myanmar being included in an extension of an existing fishways project in Laos, funded by the Australian Government, and two other Australian funded projects (Australian Water Partnership and ACIAR funding) that involve fish passage. Myanmar is now one of the five Greater Mekong countries that will participate in developing fishways on agricultural infrastructure that are impeding fish migration. This fish passage project has continued to the stage where a fishway will be built in Myanmar as a demonstration fishway.
Additionally, the Delta Flows project has provided a lot of support and information on how fish migration and the use of techniques of otoliths can help determine where infrastructure might affect migratory routes of fish. Concentrating on a key species such as the Hilsa Shad in Myanmar, a very commercially important species which migrate between the Bay of Bengal and inland rivers has provided incentive to the government to invest in fish friendly infrastructure, and has also led to closer ties between Myanmar and Bangladesh wanting to work together on the Hilsa fishery.
Similarly, in the Mekong, the concentration on Krempfii Catfish a commercially important species which migrates from the sea all the way inland through Cambodia, Vietnam and high into Laos has also given premise for the Mekong countries to work harder together on providing access to allow Krempfii to migrate. Laos and Myanmar have also continued to work together more closely on fish migration and passages, resulting in Laos representatives visiting Myanmar and initiating high level talks with the Minister of Agriculture, Livestock and Irrigation, Department of Fisheries in both 2018 and 2019. This has then resulted in Myanmar high officials visiting Laos to see some fishways and how they work.
Next steps
Informing the public of the importance of fish migration for local livelihoods and healthy ecosystems remains an important activity to keep the issue high on the political agenda. As such, WWF (with whom Delta Flows has collaborated for information dissemination and advocacy activities) has produced a short informative video on fish migration. watch the video here.
A series of guidelines and presentations have been prepared for conducting fieldwork and analysing of samples and during the project was followed in both basins where the same protocol was used for collecting data. This protocol has been improved and is now the standard for otolith collection in Myanmar and Laos. In relation to producing guidelines for each basin in relation to fish migration and infrastructure risk, the information from Delta Flows will be used in a new Australian Water Partnership Project in collaboration with Charles Sturt University and FAO who will work on developing regional fish passage guidelines for Myanmar and Indonesia. It is also being included in the next phases of the regional based Myanmar Fisheries laws to include migration, and within the upcoming 2020-2025 infrastructure investments program within the Ministry of Agriculture Livestock and Irrigation. Credibility and scientific standing for the project outputs have been substantiated with the publishing of a journal article titled Migratory fishes in Myanmar rivers and wetlands: challenges for sustainable development between irrigation water control infrastructure and sustainable inland capture fisheries. This journal article is part of a special research front on Irrigation and Fisheries for Sustainable Development.