Pollution in the River Teifi is threatening otter populations, experts have revealed. 

The Wildlife Trust of South and West Wales has sounded the alarm that if the health of the country’s longest river continues to decline, so will the numbers of the playful semiaquatic mammals.  

The trust has called on landowners, water companies and environmental regulators to work together to reduce levels of harmful pollutants in the river such as nitrates and phosphates – as well as sewage.   

Otters are a near-threatened, protected species and are considered an ‘important biological indicator’ for the health of waterways.  

The trust says their presence maintains a flourishing ecosystem around the Teifi. West Wales is home to one of the healthiest otter populations in the country. 

The Teifi’s health has been on the radar of authorities for several years, with pollution caused by slurry and agricultural run-off a particular concern. 

Reserves manager Nathan Walton said: “Otter populations across Britain have been gradually recovering from significant declines in the 1970s.  

“However recent reports for certain areas of Wales, which includes the River Teifi, show a clear decline in numbers.   

“The otter is an important biological indicator for the health of our rivers and wetlands.   

“We know that the state of most of our rivers is in a poor condition and so it is not surprising to see the impact this has on species dependent on them.  

"It is hoped that with further action on improving the health of our rivers by undertaking measures such as reducing pollution incidents, removing invasive species and better controlling run off from farmland that species such as the otter will begin to thrive once more.”  

Geoff Liles, who runs the Otter Consultancy in Newcastle Emlyn, told the Cambrian News the decline in otter numbers is mainly down to habitat loss which has heavily reduced insect life and fish populations.  

He has dedicated his life to working to preserve their presence and describes their dwindling numbers as ‘depressing but inevitable’. 

“Until relatively recently the Afon Teifi has been one of Wales’ and the UK’s otter strongholds, with its estuary, rivers, streams, ditches, ponds and wetlands all providing otters with the food and secure sleeping and breeding habitats on which they depend,” he said.  

“The Teifi, like most of our river systems, is in poor health because it is under huge threat from pollution and habitat loss.  

“The Teifi catchment has suffered severe pollution incidents over many years, reducing insect life and fish populations.  

“Results of our habitat surveys have highlighted how changes in land use and management along watercourses (such as clearing scrub; creating bank-side footpaths; introducing grazing; felling trees) have led to the loss of secure, undisturbed places where otters can sleep and breed. 

“The declining health of the Teifi (and all of our rivers) can be reversed, but it will only happen if the government urgently introduces legislation that forces through the changes that are needed.  

“Simply ‘encouraging’ businesses and individuals to stop polluting rivers and damaging habitats is not sufficient.  

“Without significant changes to the way in which we use and manage rivers, otters and many other species will continue to decline.” 

He added that the Teifi has historically been an important research site for ecologists studying otters, with the first research paper on the native Eurasian Otter being carried out in the Cletwr, one of the Teifi’s tributaries, in the 1950s.  

The Teifi saw the second longest total duration of discharges of any river in Wales last year. There were about 1,900 separate discharges in the Teifi equating to about 14,000 hours of overflow.       

Ceredigion County Council was compelled into acting after dangerous phosphate levels prompted a total pause of nearly 100 planning applications along the length of the river. 

Carol Fielding, Ceredigion Environment Team Leader for environmental regulator Natural Resources Wales, said: “The 2021 sixth Welsh National Otter Survey showed a substantive decline in their populations for the first time since the 1970s, from around 90 per cent occupancy in 2010 to 70 per cent in 2015 to 2018.

"The declines were not universal but the worst affected regions included the Teifi catchment.

"We have recently undertaken a more in-depth survey of otter within the Teifi catchment and we are reviewing the results prior to taking any necessary actions.

"We continue to undertake river restoration on the Teifi and take action on water quality issues.”