Cormorants on the rivers

[Steve Arnold]

In France anglers are often talking about the cormorant problem. On the Lot, an area that I frequently fish is a resting place for many cormorants, as well as a spawning ground for barbel. Yesterday, I was in Cajarc drinking a glass of wine with my wife in a riverside bar, and what we could see on the river was not pleasant!

A hundred cormorants were working as a team up the river, chasing panicked fish to their doom. They would work their way up a stretch of river, about 300 metres, then surface and fly back downriver and repeat the process. They did this twice in the 30 minutes we sat watching. This might be viable if they hunted mackerel at sea, but the stocks of small fish in the rivers are nowhere near large enough for such a degree of predation.

Many of the fish I catch, some quite large, have wounds from cormorant strikes. One of my favourite fishing stretches is shallow and these bids roost nearby, the fishing is a shadow of what I could expect just three years ago!

Sorry for the poor photo but my phone camera on full digital zoom, into the sun, was only just good enough to get an image. I can still count at least 90 cormorants in that shot!

 

[peterjg]

Cormorants are a daily sight when fishing. There are so many cormorants (and otters) on the Thames it's a wonder that there are any fish left!

 

[@Clive]

Same here Steve. On one of the lakes last year you could have filmed an Attenbrough type wildlife documentary. They act like a pack and drive roach shoals towards the dam. It happens every winter yet the fisheries department recently added another 60 to 80 pike in that part of the lake. I wonder why I haven't catch any large roach there recently

On the River Vienne they are more numerous in winter, but present all year. I haven't seen any control measures being used since around 2014.

 

[John Aston]

They are an issue but non lethal control has worked on our big pit. We had a major problem and a combination of lethal (licensed, BTW ) and scaring tactics seems to have resulted in lots of over fliers but few landers .

I take no pleasure in killing cormorants and am happier to let loose a couple of barrels in their vicinity .

Like many aspects of angling , I'm afraid that some anglers and clubs prefer moaning to doing something. Some organised and regular scaring with shotgun and /or starting pistol worked for us.

 

[@Clive]

They are very wary and have keen eyesight. Just being there is often enough to divert incoming birds elsewhere.

The tactics that John describes used to be employed by the Charente, Vienne & Haute-Vienne departments of fisheries except that they did shoot them. It was similar to how we dealt with excessive wood pigeon numbers in that the three departments, or in our case farm pest controllers, arranged for everybody to turn up on their respective patches at the same time. That bounced the birds around without them finding safe havens.

When we first arrived in France we rented a cottage on a farm that had about 3 miles of the Vienne bordering it. On Saturday evenings in winter vehicles from the Charente Departement de Pêche would arrive on the farm and the volunteers dispersed along the length of river bank. For about an hour around dusk there would be gunshots heard near and far. In the last ten years I haven't seen the tactics being used and the numbers of cormorants and gooseanders has risen significantly in winter.

 

[nottskev]

I'm getting the impression, as with river pollution more broadly, that much depends on where you live and fish, with huge disparities between areas, and anglers, naturally, coming to different conclusions about the scale of the problems. Four out of five of the rivers local to me are now way inferior, two drastically so, to their states and stocks when I moved here twenty years ago The middle Trent valley is cormorant central. While the river itself somehow thrives despite them, many of the adjacent lakes and gravel pits have no more than a shadow of their former fish stocks, notwithstanding the efforts of clubs or owners (scaring, legal shooting, fish refuges, lines on poles across the water, stocking bloody carp etc etc) to protect from cormorant predation. I was a member of the Young Ornithologists Club at age 10, but I can't find a good word for the inland cormorant or the inland cormorant colony, both so grotesquely alien and out of scale with their environment and so damaging to fisheries.

 

[flightliner]

I went fishing on the tidal Trent about twenty five years ago, on arrival there was was an EA land rover in the car park.
My friend, ever curious, asked what they were doing, their reply was to do a body count of the comorants on a known bend of the river but as it was raining heavily they were waiting for it to stop, So as the swims we wanted were popular in the same area as the EA were going to survay we wasted no time and legged up to the bend.
On arrival we both counted some forty nine Comorants divng down to catch a fish.
By the time we had tackled up and started fishing the rain had all but stopped and the majority of the Comorants had cleared off, presumably on account of the disturbance they had made.
About fifteen minutes later we saw the EA guys approaching and they started their count which, if i remember was four that they logged in a book.
We said that if they had got there when we did they would have seen forty nine of the - - gg-rs to which they replied "we can only book what we see". Then they left!
NB, we had seen plenty of the birds in the past few years ( winter only) in the past they usually surfaced with a silver fish but tha particular winter all they surfaced with was eels

 

[silvers]

I'm getting the impression, as with river pollution more broadly, that much depends on where you live and fish, with huge disparities between areas, and anglers, naturally, coming to different conclusions about the scale of the problems. Four out of five of the rivers local to me are now way inferior, two drastically so, to their states and stocks when I moved here twenty years ago The middle Trent valley is cormorant central. While the river itself somehow thrives despite them, many of the adjacent lakes and gravel pits have no more than a shadow of their former fish stocks, notwithstanding the efforts of clubs or owners (scaring, legal shooting, fish refuges, lines on poles across the water, stocking bloody carp etc etc) to protect from cormorant predation. I was a member of the Young Ornithologists Club at age 10, but I can't find a good word for the inland cormorant or the inland cormorant colony, both so grotesquely alien and out of scale with their environment and so damaging to fisheries.

Notable absence of small fish for the Riverfest final at Burton Joyce … those more local than I put it down to cormorant herding.

 

[Alan Whitty]

Sadly I think your lack of silvers on the Trent is more down to conditions, when rivers are not right you ain't catching em, as we all know certain rivers are full of roach, or dace, or perch, then hey-presto their gone, then we anglers being such cockles gits believe they are dead, or eaten, nothing to do with the fact we are useless when they shut their mouths, lol.

 

[nottskev]

Sadly I think your lack of silvers on the Trent is more down to conditions, when rivers are not right you ain't catching em, as we all know certain rivers are full of roach, or dace, or perch, then hey-presto their gone, then we anglers being such cockles gits believe they are dead, or eaten, nothing to do with the fact we are useless when they shut their mouths, lol.

I did say there's no shortage of roach etc in the Trent in my area - it's the nearby stills, including formerly great silvers waters, that remain, many of them, decimated, and the tribs which seem afflicted by additional problems. As for them being there but not feeding for us, counting the cormorants and doing the math re weight of fish eaten per bird per day tells us no small quantity will never open their mouths again .... It's true that for a long time the silvers on the river around here baffled everyone by a winter vanishing act, but that's a different matter, and the "catching season" seems to be lasting a bit longer in recent years. I do factor in my own incompetence to catch, but there's no disguising that both mysterious fish shoaling/movement and cormorant predation are in play and likely related.

 

[@Clive]

In the lakes that I fish the roach shoal up in the deeper water close to the dams in November through to January. If the cormorants aren't there I would expect to be able to catch roach almost from the off with the catch rate increasing as the session goes on. On the two or three occasions that I fished after disturbing large flocks of cormorants on my arrival, I have caught nothing for over two hours. It is the same when anglers in float tubes go past. It unsettles the fish.

Similarly, in 2012 to 2015 pre-cormorants the size of the roach that I caught were much bigger than I get now.

 

[Alan Whitty]

On the Dorset Stour lower reaches, the tidal and bottom of Throop are full of silver fish, have been for years, yet the cormorants are plundering it continuously, summer and winter, yet still numbers of silvers seem strong the next season, it is true predation majes a difference but silvers seem to be able to boost successful spawning to counteract it, God knows how...

 

[Philip]

A hundred cormorants were working as a team up the river, chasing panicked fish to their doom. They would work their way up a stretch of river, about 300 metres, then surface and fly back downriver and repeat the process.

I have seen exactly the same thing on the Seine..amazing sight .the surface of the river was almost boiling with splashes as dozens of birds dive at the same time as they work their way down as a large group.

While fishing I have counted over 100 birds sat in trees opposite me on the river with probably the same number airborne.

 

[silvers]

Sadly I think your lack of silvers on the Trent is more down to conditions, when rivers are not right you ain't catching em, as we all know certain rivers are full of roach, or dace, or perch, then hey-presto their gone, then we anglers being such cockles gits believe they are dead, or eaten, nothing to do with the fact we are useless when they shut their mouths, lol.

Up to a point … but they were absent for the whole summer… whilst plenty caught on other stretches.

 

[Alan Whitty]

But that stretch is plundered by match anglers, look how poor Evesham has been over the years where often matches were fished up to 5 days a week, I'm not saying it definitely isn't down to cormorant predation, just that the fish could still be there, at Stewartby lake near Bedford we used to catch up to 100lbs of quality roach, then the cormorants turned up in numbers, you couldn't buy a bite, well not until half an hour before dark anyway, I decided to make a slider up with an isotope and try fishing into dark, for several trips I caught around 30lbs of roach in two hours or less doing this, the roach simply weren't prepared to feed in daylight, so maybe the dace and roach on the Trent are up to the same... I wouldn't blame em.

 

[Mark Wintle]

On the Dorset Stour lower reaches, the tidal and bottom of Throop are full of silver fish, have been for years, yet the cormorants are plundering it continuously, summer and winter, yet still numbers of silvers seem strong the next season, it is true predation majes a difference but silvers seem to be able to boost successful spawning to counteract it, God knows how...

I've found the last couple of years dire on the lower Stour, still some fish but there's a real absence of roach and dace all the way through from Wimborne downstream. The upper river is also more patchy, with the quantity and quality well down.

On the Frome the problem is not improved by frequent forays by seals from Poole Harbour.

 

[Alan Whitty]

Now seals, that's a different beast, on the Stour this year guys float fishing were telling me it wasn't fishing well (and the fish had gone), but when your barbel fishing(which was also crap) with pva bags your rod tip is being battered with roach and dace ripping it open to get the goodies, again, just because we don't catch much doesn't mean they aren't there, add to that the roach start topping just before dark in all the swims they proliferate, as I said earlier, decent anglers that are used to catching often think that when they don't, fish are absent, bur over the years I've seen this happen a lot, nobody mentions the fact that sewage going into the river daily could be having a detrimental factor on fish feeding....

 

[John Aston]

You are so right. Not aimed at anyone here but I get so tired of anglers telling me there's no fish and the reason for their absence . It can be anecdotal nonsense - 'no fish since they built the bypass', 'otters ate them all', 'Europeans.. (hold on I'm European too)... took them all' , followed by 'no mate haven't fished there for years- no effing fish innit '.

As a community we are bad at data collection and analysis , and prefer simplistic and glib explanations. Problems can have not one, but many causes ,some linked , others not - climate change(bigger floods , hotter summers, poor fry recruitment ) , sewage and/or chemical pollution , collapse of invertebrate population , agricultural run off, abstraction, one off pollution event , invasives as well as the old favourites of predation and poaching. I try to do my bit with bug sampling and water quality tests but it is frankly horrifying how few anglers show any interest . Instead it's the predictable call for restocking - FFS why do that when a river is in trouble ??

It's complicated and I think (with honourable exceptions like the Feargal Sharkies in our number) anglers oversimplify and often actively distrust any scientific analysis of a 'problem river' . I've even had one club tell me - without a scrap of evidence why there were fewer fish - " it's the XYZ estate doing drainage work , but it's been hushed up by the authorities " . I was the chair of the local fisheries forum at the time and I volunteered to help (FoI , contacts at EA, WTT , AT etc , as well as bug and water testing ). But guess what - I'm still waiting for their call ....

 

[steve2]

I have never understood why we restock rivers before finding out why they need restocking.

 

[bennygesserit]

interesting link from British Trust For ornithology unlike otters which have been here for yonks cormorants only came inland circa 1980 a recent addition of a top predator is bound to make a difference e.g. have Magpies had an effect on sparrows