One day on a dai

A Cambodian fishing platform worked around the clock and hauled in nearly 30 species despite another slow season

January 28, 2022
One day on a dai
A photo illustration of 16 of the nearly 30 species researchers from Wonders of the Mekong documented during their survey of the catches from the dai platform. Illustration by Emilie Languedoc and photos by Anton L. Delgado for Southeast Asia Globe. Front wave, left to right: Redtail botia (Yasuhikotakia modesta), Smith’s barb (Puntioplites proctozysron), Betta fish (Betta siamorientalis), Siamese mud carp (Henicorhynchus siamensis) also known as trey riel in Khmer and Boseman croaker (Boesemania microlepis). Middle front wave, left to right: Sevenspot archerfish (Toxotes chatareus), Red Eye puffer (Carinotetraodon lorteti), River sprat (Corica laciniata), Freshwater garfish (Xenentodon) and Pale rasbora (Rasbora aurotaenia) Middle back wave, left to right: Blackhand paradise fish (Polynemus melanochir), Sheatfish (Phalacronotus sp.), Shark catfish (Pangasius sp.) Back wave, left to right: Giant sharkminnow (Osteochilus schlegelii), Banded loach (Syncrossus helodes) and Puzzle barb (Crossocheilus reticulatus)

The steady hum of a bag net being drawn from the Mekong River, followed by the thump of the catch spilling onto the platform floor, composed the rhythmic soundtrack of a dai platform. Each net came in with hundreds of kilos of fish and each of the 24 hours brought a fresh haul.

With migration season ending in February, the dai fishermen near the city of Longvek on the provincial borders of Kampong Chhnang, Kampong Spueu and Kaandal were fervently trying to make up for what they considered another season of light catches.

“Fish have been declining each year and the catches we are getting this month are still low, even though it is supposed to be peak season for fish,” said Sothon Chet, who has been a dai fisherman for eight years.

Five of the ten lowest annual water flows on record in the Mekong River have taken place since 2010, according to an analysis by the Mekong Dam Monitor of data from the Mekong River Commission. This steady stream of low water flows threatens fish biodiversity and populations, and thus the livelihoods of fishermen like Chet.

A hammock provides respite after a busy day at the dai

“This migration is important because these fish are used for everything from prahok, to fish sauce and other products,” said Bunyeth Chan, a postdoctoral researcher with Wonders of the Mekong, a USAID project. “Cambodians and people across the basin are highly dependent on fish for food and finances.”

Dai is Vietnamese for “bag.” In this context, dai fishing refers to “stationary trawl” or “stationary bag net” fishing.

Chan said the fisheries work indiscriminately, taking in whatever they can catch and unintentionally aiding researchers.

“These dai platforms catch all kinds of species at any size, from the top of the river to the bottom, from the largest fish to the smallest,” Chan said. “This means we also catch a lot of information because the nets catch most of the migratory species we are studying.”

While stepping on stray fish, slipping on slime, eating prahok fish paste and napping in hammocks, the Globe took nearly 3,000 photos and almost 50 minutes of video to partner our feature on the impact of record low water flows on the Mekong’s communities and environment. Here is a look at a day on a dai:


The dai fishery’s first row of platforms by Longvek, a little more than 40 kilometres from Phnom Penh, hauled in between 350 to 500 kilos (about 770 to 1,100 pounds) of fish with each bag net. There is one net per dai platform, which when full can only be pulled from the Mekong and its tributary, the Tonle Sap River, by a combination of manpower and machinery. For most dai platforms these catches are brought in 24/7 during fish migration season. In Cambodia, that season generally goes from mid-November to mid-February. These images are from the peak period of January 11th to 15th. 


After the bag net is pulled from the river, the haul is unceremoniously dumped onto the deck of the dai platform. The following minutes are filled with fish flipping across the floor in a desperate attempt to flop to freedom. Not a single fish seemed to make a successful escape back into the Mekong.


Once the haul is dumped on deck, a crowd of humans descend on the fish to sort the catch. Either by hand or armed with tongs, men and women toss the fish into baskets in two categories: large and small. The larger fish, usually more profitable, are often cooked on their own. The smaller fish are processed into products such as prahok – a salted, fermented paste common in Cambodian cuisine – and fish sauce. 


When sorting through each catch, dai fishermen often engross themselves in the work. The smallest of fish often find their way into every crack and crevice.


Researchers from Wonders of the Mekong measure and remove a 5-kilogram (11-pound) sample from every other haul for surveying. Sequestered at the corner of the platform, the researchers identify, measure and weigh each fish within the sample. In the course of 24 hours, the team documented nearly 30 fish species caught by 12 different hauls.


Sixteen of the nearly 30 species the research team from Wonders of the Mekong documented during their survey of the dai platform catches. From left to right, top to bottom: Freshwater garfish (Xenentodon), Redtail botia (Yasuhikotakia modesta), Banded loach (Syncrossus helodes), Sevenspot archerfish (Toxotes chatareus), River sprat (Corica laciniata), Puzzle barb (Crossocheilus reticulatus), Betta fish (Betta siamorientalis), Shark catfish (Pangasius sp.), Blackhand paradise fish (Polynemus melanochir), Giant sharkminnow (Osteochilus schlegelii), Pale rasbora (Rasbora aurotaenia), Boseman croaker (Boesemania microlepis), Sheatfish (Phalacronotus sp.), Redeye puffer (Carinotetraodon lorteti), Siamese mud carp (Henicorhynchus siamensis) also known as trey riel in Khmer and Smith’s barb (Puntioplites proctozysron). 


When approximately 20 baskets of small fish are separated from the hauls, the dai fishermen take them to a nearby processing station, where the fish are minced, diced and stored for eventual use in various products.


Sothon Chet, who has been a dai fisherman for eight years, said a decrease in the number of hunting birds is proof of the lack of fish during recent migration seasons. At the end of dai platform 15E, he pointed towards a small flock diving into the water for dinner. “See how few there are? When we have a normal year of fish, there are thousands of those birds. Now look, less than a hundred.”


Sleep is difficult to come by on dai platforms, which often operate around the clock during migration season. Late into the night, the lights from the mouth of the platforms illuminate the darkness and stretch across the width of the river.


Cambodia’s main dai fishery consists of 15 rows of dai platforms stretching from platform 15E by Longvek, pictured here, down to Phnom Penh just over 40 kilometres (about 25 miles) away. The last row of platforms is just north of the Sokha Hotel in Chroy Changvar, the northeast district of the capital. Each row has three to five platforms, totalling just over 60 platforms for the entire fishery.


Entire families live on dai platforms during fish migration season. With hauls coming in every hour of the day, it doesn’t make sense to stay anywhere else. Despite their proximity to work, the fisherman and their families still have to make short commutes away from the river to resupply.

Text and photos by Anton L. Delgado for Southeast Asia Globe


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