Background
American mink entered U.K. rivers and waterways from poorly maintained fur farms and towards
the end of the last century there was a “mass release” by Animal Rights Activists. Since then,
American mink have decimated the water vole population in the U.K., making the water vole,
“Britain’s fastest declining mammal”.
Therefore, it is important to monitor that mink are not present in order to start restoring water voles
and other biodiversity to Britain’s’ rivers.
Meeting in Radwell 31st March
A group from RevIvel met with Josh Kalms, Water Vole Conservation and INNS Officer at Herts and Middlesex Wildlife Trust 31st March. The purpose of the meeting was to ensure mink monitoring
rafts were placed in two strategically important locations to protect Hertfordshire’s’ rivers from
mink coming upstream.
Firstly the “standard” mink monitoring raft in/ near the Mill Pond at Radwell (installed about
a year ago) was checked and evidence of mink footprints was noted in the wet clay area
within the raft
Secondly, a new Smart raft was installed in another strategic section of the river




How the Smart raft works
If an animal is captured, a text or email alert is generated to nominated individuals at RevIvel. The
raft will be checked as soon as possible or in any event within 12 hours if triggered. There is no need
to check unless alerted as there is “pulse” monitoring in place.
Animals other than mink (e.g. moorhens) should be released. Mink need to be dispatched swiftly
and humanely.

Looking forward
HMWT is considering locations for water vole reintroductions in rivers in North Herts in 2022 – one
such area under consideration is the Hiz. Next year – assuming no mink and water in the river
(Affinity Water, please note!) – the upper Ivel could also be a candidate for water vole
reintroduction.
Water voles are a vital part of river ecosystems and are a keystone species. Their burrowing, feeding
and movements help create conditions for other animals and plants to flourish. Ultimately also
helping achieve the mission statement of RevIvel which is to create an environment whereby brown
trout and ranunculus may once again thrive in the upper Ivel.