Mr Tansley said the decision to eliminate the mink population across Essex and the rest of the region had not been an easy one, but they had carefully weighed up the impact the predators were having on local wildlife.
“It’s really difficult, and it’s particularly upsetting for us as officers to have to do that sort of work, because we join a wildlife trust to protect animals,” he told the BBC.
“But the important thing was to decide, do we want a future where we have mink and very few other species on the river? Or do we remove the mink and allow natural wildlife to rebound and come back in force?
“We’ve shown that, yes, it can be done at this sort of scale.”
Mink are trapped for culling using floating platforms, or “smart traps”, which are fitted with a special excluder to prevent water voles and birds getting in.