Otters are prime suspects in fish raids on local ponds

OTTERS are suspected to be responsible for a number of raids on ponds in Westbury and surrounding villages, killing expensive pond fish.

Westbury Leigh local Trevor Weaire who lives near Biss Brook discovered that 33 of his 34 pond fish, worth approximately £3,500, had been killed and scattered across his lawn. “In the early hours of Monday morning last week, around 2.30am, I heard a noise in the garden, a splash, but couldn’t see anything,” explained Trevor.

“Later that morning I discovered that 33 of my 34 fish, including koi carp, had been killed. All their livers were missing, which is what otters do, they eat the livers and leave the rest.

“All the frogs that live in the pond had been killed too, another sign that it was an otter.

“Luckily I found one fish still alive on the lawn and quickly got him back into the pond.

“We live about 300 to 400 yards from the brook, so the otters have travelled a fair distance to get to the pond.

“It’s definitely not a heron as it happened at night, plus some of the rockery around the raised pond had been demolished to gain access to the pond.

“Unfortunately I can’t claim on my home insurance as livestock aren’t covered in the policy, but I will replace the fish in spring next year.”

Other Westbury locals have also reported similar incidents on the Spotted Westbury Facebook page, with ponds as far as Heywood and Hawkeridge believed to have been cleared out by otters.

The number of otters in Wiltshire have been steadily increasing over the past 15 years, with the Bristol Avon and its tributaries now fully colonised.

Steve Smailes, wildlife information volunteer for Wiltshire Wildlife Trust explained, “Otters will tend to explore watercourses right up to their sources, all the tiny headwaters and ditches,  and  in the process will nocturnally venture a little way away from the immediate river corridor, to fully exploit the feeding possibilities in their territories.

“Feeding possibilities involve chiefly (but not exclusively) fish, and should an otter come across a pond stocked with fish, it will naturally be interested.

“Some ponds they will find, most they won’t.  Luck will play a part, and proximity to watercourses.  This can be a particular problem for people with precious collections of Koi carp, which are both sizeable and highly visible.

“Otters will eat the most nutritious/tasty part of the fish when food is in plentiful supply. When food is short they are more likely to eat the fish entire – depending on the size of the fish of course.

“The otter is not the only raider of ponds – the mink, a smaller but related non-native mammal, will not pass up a fish supper if it finds one, and the heron is a resourceful plunderer of ponds at first light when the homeowner is probably (in the warmer months at least) still tucked up in bed.

“So, the picture is not clear-cut, but some pond raids are clearly the work of otters.

“Where otters have increased in number, mink have been in decline, and I know for certain that otters have been responsible for some fishpond raids.

“It would not be that easy to distinguish between mink and otter raids.  Raids might involve more than one individual – a mother and cubs for example. Either mammal might kill more than they need, though mink are more likely to remove and stash the dead fish.

“The sheer physicality of an otter raid might be apparent, for instance the weight of fish they can tackle – otters weigh up to 10 times as much as mink, and can catch and subdue very large prey – and the rearrangement of in-pond furniture might give a clue.

“Having said that, mink are quite ferocious and determined, so they do punch above their weight.

“A sand trap (an unobtrusive tray of flat damp sand) by the pond might possibly get you a clear footprint to identify, and any faeces found nearby might be examined. Otter poo is reputed to smell a bit tarry, vaguely of jasmine, or at least, not unpleasant.  It is also likely to contain visible fish scales and bones, and be in a conspicuous place near water.”

With netting proving no obstacle for otters wanting to gain access to a pond, the Wiltshire Wildlife Trust suggest a more secure way to protect fish. “A metal grid, secured well above the water and with no access underneath (blocked or bricked up around the perimeter if necessary) is probably the only sure way to make a garden pond otter-proof.  The grid should be fine enough to keep out both otter and mink.”