If you stand on a bridge for long enough around here someone will come past who will stop to bemoan the passing of the fish. They will tell you about the trout they tickled in childhood and the salmon their grandfathers netted when times were hard. They may also tell you how they outwitted the game keeper in their youth.
The only trout we’ve seen in our stream, that was more than an inch long, arrived in a bucket taken from the boot of a car, caught elsewhere by a friend’s grandson and rehomed in our stream, never to be seen again.
Accepted wisdom blames acid rain, too many pine trees, insecticides washing off the backs of the sheep, the reduced use of lime on the fields, too much sewage running into the water, not enough sewage running into the water, over fishing, weirs, flooding and sheep dip.
Now, we’ve just acquired a trail camera which we’ve placed by the stream in an isolated open area (most of our stream has cover) and guess what the first thing we spotted was — not an otter (sadly)
European Otters
but a mink who appeared to be (guess what?)… Fishing!
Mink! by jsutcliffe (CC BY- NC-SA 2.0)
The following day, shortly after dawn, we spied a heron patrolling the same stretch of water. What are they up to, if there are no fish? I know they do eat frogs. Or are they the reason that there are no fish?
Lots of the streams in this area have pasture right down to the water’s edge so that any fish that there might be have no cover from overhanging vegetation which is what they need to hide from these dastardly predators.
The problem is what to do about it. Bring back the game-keeper? I know what he’d do!
The predators that the game-keepers used to kill are perhaps more common than we thought — we just don’t get up early enough these days to see them.
dianaashworth 
If I remember correctly, mink are not native to your country. Like nutria (coypu) over here, they were brought in for the fur trade, and either escaped or were released. Humans around the world have historically have either imported or brought plants and animals along with them that they find useful, without knowledge or consideration of the consequences.
Brilliant as usual Diana! When we first moved here we told that there was a mink in our stream that had taken the previous occupant’s chickens. Over the seven years we’ve been here we have never seen it. Perhaps a new alarm clock is in order!
J > Mink are voracious predators. In the Outer Hebrides they – and hedgehogs (which are also alien to the islands) had decimated wild bird populations (by predating the eggs on the nest, and the mink also kill the chicks). Both species have now been brought under control (hedgehogs by relocation to the mainland), and wild bird populations have recovered.
Thanks for that information. We need to assess the scale of our mink problem and will certainly tap into the Hebridean experience.