It is a centuries-old tradition in Wales, but coracle fishers on a major river have said pollution has meant there are "no fish" left.
Testing by campaign group Save the River Tywi showed evidence of industrial, agricultural and human waste pollution, with fishers saying they often see dead fish bobbing up and down in the water.
One fifth-generation coracle fisherman described the situation in Carmarthenshire as "dire" after only catching one fish in the three-month season between May and July.
Natural Resources Wales (NRW) said it took all reports of pollution seriously and had "a number of ongoing enforcement and compliance investigations within the Tywi catchment".
The tradition of coracle fishing has been part of life on the Tywi for centuries.
Typically done at night, fishermen use small rounded boats with nets cast among them to catch salmon and sewin [sea trout].
It was once an important livelihood in west Wales, but today it is mostly a heritage tradition, rather than a full-time source of income.
US President Jimmy Carter even loved fishing in these rivers, but according to fishermen, recent pollution has made it impossible.
Chairman of Carmarthen Coracle and Netsman Association, Andrew Davies, said he thought the four coracle men on the Tywi had caught 12 fish among them in the whole of the 2026 season when, a few years ago, "you'd catch that many in a night".
Keith Elias's family have been fishing on the river for 300 years - he said he had only caught one fish this season.
"It's been in my family for so long, I love carrying the tradition on, but it's getting to the point where you get to the end of the season and you're not hitting fish.
"You just don't want to go."
Last year, the nearby River Teifi had been noted as one of the UK's most polluted rivers, with 2,232 spills lasting more than 22,000 hours recorded in 2024.
It has been reported that some incidents of pollution were made by Welsh Water.
The company said it would invest £889m on storm overflows between 2025 and 2030, including six projects to reduce their impact on the Tywi.
It added: "We are determined to play our part to improve river water quality on the Tywi, but this isn't just an issue for water companies, collaboration is needed across sectors, including industry and agriculture, to ensure improvements."
Local people have also shared videos online of discharge across the river, which they claim appear to be from a nearby electronics recycling company Mekatek.
The company has a discharge licence from NRW.
Mekatek said it shared concerns about the drop in sewin and had spent more than "40 years developing and improving our processes to ensure we are not a factor in that reduction".
It added: "Anyone wishing to understand what we do and how well we do it is more than welcome to arrange to visit the site and view our operations for themselves."
Davies, 63, said this year's season had been "a write-off"
"I've been fishing for 38 years, I've never seen a season as bad as this," he said.
"When I first started, this river was black with fish, it was alive with fish. But it's gone now - there's no life in the river."
He said only four fishing licences had been taken out this year, compared with 12 when he started: "People have just, I won't say given up, but the enthusiasm's gone."
He said that the bad smell coming from the river "doesn't help" and he and others had reported cases of pollution to NRW "all the time", but "nothing seems to be done".
"I think something needs to be done to clean the rivers up in Wales, people have been dodging the bullet," he said.
Citizen scientists on behalf of Save the River Tywi, who have been conducting tests on the river, said there had been evidence of pollution coming from farms, companies based along the river and people.
Mayor of Carmarthen Russell Sparks said the river had been in a "really tough situation".
He added: "Over the last couple of years it's been really sad to see it, feel it and smell it."
Sparks said the smell was a combination of pollutants and algae blooms "creating this negative cycle".
Carmarthenshire MP Ann Davies wants "firmer action taken" against those who "constantly pollute the river".
She also said - as someone who farms herself - farmers have a responsibility to not pollute the river, along with people and businesses.
"We have a collective responsibility on what we buy, what we flush down the toilet."
Huwel Manley, head of south-west operations for NRW, said "Like many rivers, the Tywi faces a range of environmental pressures, including pollution and is also impacted by the current dry weather conditions which are seeing an increase in the water temperature along with wider ecological challenges.
"We take all reports of suspected pollution seriously. We currently have a number of ongoing enforcement and compliance investigations within the Tywi catchment, including cases that are progressing towards court proceedings."
The Welsh government said: "The Tywi is one of Wales' most important rivers, supporting internationally important habitats and species, local communities, recreation and cultural traditions such as coracle fishing."
It had been "aware of recent concerns regarding foam, odours and discolouration in the River Tywi" and "NRW have investigated and confirmed the impacts were linked to natural environmental conditions".
It said NRW had been investigating a separate potential source of pollution entering the Tywi and as those investigations remain ongoing, it would be inappropriate to comment further.
