Cambodia has a marine mammal problem. Dolphins, dugongs and other species are caught and killed in fishers’ nets or wash up dead on beaches regularly, but no one knows how many, exactly why or how to stop it.
To fill the void of data, a local NGO trained residents of 36 fishing communities along the country’s coast to join a nascent citizen scientist network documenting incidents of marine mammal bycatch and strandings.
The NGO, Khmer Ocean Life, delivered training sessions across Cambodia’s four coastal provinces — Kampot, Kep, Koh Kong and Preah Sihanouk — through July and August 2024.
By leveraging fishing communities’ local expertise and presence on the water through the citizen scientist network, the group will track the frequency of bycatch and strandings and identify hotspots. The data will inform mitigation strategies to preserve Cambodia’s marine biodiversity.
The training sessions, delivered by staff from Khmer Ocean Life and the Fisheries Administration, aimed to develop fishers’ understanding of different marine mammal species.
Community members learned how to identify the most common ones by shape, colour, size and features; how to use the personal protective equipment (PPE) needed when handling dead animals; and how to record physiological and geospatial data about bycatch and strandings on a simple form. They also learned how marine mammals fit into the broader marine ecosystem.
“This is what we want the communities to understand,” said El Lokkaman, a project assistant who delivers the trainings. “That dolphins and marine mammals play an important role in the livelihoods of fishers, they help to maintain seagrass meadows, which in turn creates habitats for crabs and fish. Before, people only saw these mammals as fun creatures, but spreading this knowledge is one of the goals of the network.”
The fishers share fishing grounds known as a community fishery (CFi) — a government-recognised zone on the water that’s reserved for a specific community to manage. Two members of each participating CFi volunteer as liaisons to the citizen scientist network and receive PPE and other equipment to collect the data.
Each community liaison agrees to investigate incidents of marine mammal bycatch and strandings and to share their findings in real-time with Khmer Ocean Life’s staff via the messaging app Telegram.
In Neang, a commune councillor at Tomnop Rolok commune in Preah Sihanouk, became one of the liaisons. In his community, 80 per cent of residents still rely on fishing as their primary source of income, and Neang said he was keen to see dolphins return as it would likely indicate a healthier environment from which his community derives its income.
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Coastal marine mammals face more intense threats due to their proximity to fishing activities. Gillnets have been highlighted as one of the fishing gears causing the most predominant threat, along with longlines, trawls, traps and surrounding nets.
Sarah Tubbs, co-founder, Khmer Ocean Life
“Since the ports expanded, we no longer see the dolphins when we go out fishing,” he said. “The water quality is not good, there is pollution from the port, pollution from the city, but I’m hopeful they will return.”
Neang was equally optimistic about the level of cooperation from neighbouring CFis. “They don’t kill dolphins for food, they are not trying to catch them, so they will tell us if they see them [caught as bycatch or stranded],” he said.
An unquantified threat to marine life
At least 10 species of marine mammals are commonly found in Cambodia, including dugongs (Dugong dugon), Indo-Pacific finless porpoises (Neophocaena phocaenoides), Indo-Pacific humpback dolphins (Sousa chinensis) and endangered Irrawaddy dolphins (Orcaella brevirostris). But all of these species, along with much of Cambodia’s marine life, face an array of threats as habitats succumb to ongoing coastal development and unsustainable fishing practices.
“Bycatch is the biggest threat facing marine mammals around the world,” said Sarah Tubbs, Khmer Ocean Life’s co-founder and co-director. “Coastal marine mammals face more intense threats due to their proximity to fishing activities. Gillnets have been highlighted as one of the fishing gears causing the most predominant threat, along with longlines, trawls, traps and surrounding nets.”
Currently, data on marine mammal bycatch and strandings are lacking in Cambodia. Even rough population estimates are scarce. Fifteen Irrawaddy dolphins were individually identified over the course of 2018 through Tubbs’ research and at least 10 fatal strandings of the species were recorded between 2017 and 2020, but these studies were confined to Cambodia’s smallest province, Kep.
Fisheries Administration officials estimated in 2020 that there were only between 15 and 20 dugongs left in the waters of Kampot and Kep provinces, although conservation efforts focused in Kep have resulted in a newfound hope for the species.
Beyond this, though, the abundance of marine mammal species and the scale of the threats they face from human activity are hard to measure.
Hoping to fill this gap in the data, Newcastle University in the United Kingdom, where Tubbs is a PhD student, conducted interviews with fishing communities across all four of Cambodia’s coastal provinces between September and November 2023.
From this, Tubbs hopes to estimate annual marine mammal bycatch across each province, but the results won’t be published until sometime in 2025. Until then, data collected through the citizen scientist network will provide real-time insights into where bycatch mitigation efforts are most needed.
Collateral damage
The need for enhanced conservation efforts off Cambodia’s coast has become more urgent in recent years as fish stocks have plummeted.
Communities along the coast reported that their fish catches decreased between 40 per cent and 60 per cent from 2017 to 2022, according to research from the Asian Development Bank (ADB). More than two-thirds of coastal fishers the ADB surveyed said their income from fishing had dropped by at least 50 per cent between 2019 and 2022, leading to a vicious cycle of destructive, often illegal fishing methods.
“We’re seeing our catches decline each year; I think it’s because there are so many illegal pair-trawlers operating in these waters, it affects our livelihoods,” said Suon Doeun, a veteran fisher who was not involved in the citizen scientist network but has worked on trawlers out of Stung Haev port in Preah Sihanouk province for more than 20 years.
Pair-trawlers take the basic concept of bottom-trawling and stretch a net, often hundreds if not thousands of meters long, between two boats, which then scoop up any and all life caught between them. Pair-trawling is illegal in Cambodia, but it’s lucrative compared with legal forms of fishing. And limited law enforcement capacity on the water has resulted in pair trawling and various other illegal forms of bottom trawling picking the waters clean with impunity.
“Pair-trawlers are destroying the marine biodiversity; the problem has become much worse in the last two years, and the natural resources have declined significantly,” Doeun said. “Years ago, the waters were bountiful, but now there are so many pair-trawlers that it is a struggle to survive. … Legal trawling, like what we do, is becoming harder as a result.”
The prevalence of such indiscriminate fishing methods is why Doeun believes he sees fewer dolphins now than he did in the past.
“They try to eat the fish out of our net; we see them following from behind,” he said. “I’ve never had one get caught in our nets, but I’ve heard they get caught in other people’s nets when they’re trying to get the fish.” This, he added, is more likely to be fatal for dolphins caught in the nets of illegal fishers, who he contended are more profit-driven and less concerned about sustainability.
Other fishers from across Preah Sihanouk province echoed these sentiments.
Speaking to Mongabay shortly after attending a Khmer Ocean Life training session, Ung Vannath, a fisher from the Ou Tres flooded forest CFi, also pointed to pair-trawlers as the reason for declining fish stocks, lost income and dwindling marine life.
“It’s not easy to capture dolphins or dugongs, but the pair-trawlers can do it — there are many of them operating out of the ports in Sihanoukville,” he said. “If they caught dolphins in their nets, they wouldn’t disclose that information because they’re operating illegally.”
Of the 15 fishers attending the training, Vannath signed on as one of the liaisons to report back to Khmer Ocean Life.
“I’m 28 years old now, but when I was 15 and learning how to fish, I saw groups of 10 or more dolphins at once,” he said. “Now it’s much smaller groups; we see them less frequently and usually farther out to sea. The decline is due to the increase in illegal fishing; many boats have nets that catch everything.”
Changing attitudes and preserving marine life
Kem An, a senior official with the Fisheries Administration in Preah Sihanouk who accompanied Khmer Ocean Life representatives at the training sessions across the province, called on communities to help preserve Cambodia’s natural resources.
“We need to change attitudes in terms of preservation,” he told a group of 11 fishers at Tomnop Rolok commune. “If we talk about the ecological system, it will continue to provide for us if we preserve it, we can benefit sustainably.”
Maintaining a balanced marine ecosystem, he said, was key to ensuring that Cambodia’s coastal waters could continue to provide a livelihood for fishers.
“We need clean water, we need sustainable fishing practices, so please do not be discouraged by restrictions to fisheries,” he said, explaining that these measures were designed to reduce the strain on marine resources.
While illegal fishing does present a threat to marine mammals, Lokkaman of Khmer Ocean Life said it is only one among several. Habitat loss, climate change, ecosystem degradation and ghost nets (abandoned fishing gear that can ensnare dolphins and other marine life) all add up to create an increasingly challenging environment for marine mammals.
“Pair-trawling happens along the whole coastline; we hear about this a lot,” he said. “People understand how that impacts their community, but there is less understanding about what marine mammals eat, which habitats they like and how it’s connected to ecosystems like seagrass meadows, which are often lost in areas that get developed.”
The rapid changes sweeping Cambodia’s coast create an urgent need for more conservation efforts in line with the country’s Aichi Biodiversity Targets and existing frameworks for sustainable development across coastal provinces.
But to do this, more data are needed to better understand the threats and how they can be mitigated. To date, Khmer Ocean Life’s citizen scientist network has filed one report on bycatch and seven on strandings, but over the coming months and years, the network aims to build a robust data set that will help guide the preservation of Cambodia’s marine life.
This story was published with permission from Mongabay.com.
