How many lbs of fish do Cormorants need to eat per day to survive?

[cg74]

cg, can I ask if you are connected to one of the 'bodies'?

It means that over predation as a prime example, leads to a shortage of prey, this results in the predator either moving on or dying, simple!

This is what it's all about cg, when the prey are gone, they are gone.....

I've recently had dealings with the E.A hotline and to be honest I have no faith in them what so ever. I sent pics and was told I would be contacted, nothing!!! No email reply and no phone call

So what's the point? Underfunded and it's gonna get worse and what are the ATr doing about it? They are aware of the comorant problems and otters, but nothing. So I'm not surprised the P.A.G has been formed.

You may ask and I will answer your question, no I am not connected to any of the groups that listed, nor do I have any desire to be.

But what I have found is unless you push and really push the issues into their faces, they will just brush you aside.

I too can see exactly why PAG has been formed.
That said around me a lot of the blame for the demise of the rivers especially, lays squarely at the feet of the clubs who control the stretches of river most severely effected by poor stocks.
I am not saying this is always the case but if you look hard I bet you'll find in one hell of a lot of cases its poor water management that is the reason no action is/has been taken.

In my area (Oxfordshire) if the biggest club controlling the river Cherwell Banbury District AA had bothered to pursue the issues being faced by the river, firstly we'd be fifteen years ahead of where we're at now and secondly the river wouldn't have ever reached crisis state.

They had one of the most prolific barbel stretches on the river, now about 6 barbel reside on it.
They also had one of the best mixed river fishery's I've ever fished now thats f****d but still they don't contact the EA, why, IMO bloody apathy!!
Happy hiding away blaming otter predation for everything, apart from Trefor West and a few that follow his hear say, nobody else blames otters for the rivers demise.
So why do they, easy, well they're protected so what can be done...... So they've got their excuse sewn up!

 

[Steve Spiller]

Thanks cg.

My club is the same too, luckily it's an amalgamation of clubs, so I can buy a cheap ticket for the bit I want to fish. The main club thinks rivers are finished, so I haven't bought that ticket. It's a great shame because they've got some seriously devoted members and bailiffs.

So where do we go from here if the club don't give a sh*te? The E.A don't want to know it and the ATr aint gonna push it..........

 

[cg74]

TBH I wish I had an answer, me I'm toying with the idea of taking on a few of the better stretches that others have dropped, forming a new club and bombarding everyone who has anything to do with environmental issues.

On my local ditch no end of reasonable short stretches have been vacated, usual denial of the facts reason given, can't peg a match on it or land owner has increased the rent.

 

[geoffmaynard]

"The thing is Geoff you like many other anglers seem hell bent on complaining to other anglers rather than to the people who count, EA, NE, DEFRA to name but a few bodies."

That's right. I help spread the word, I hope. Apart from supporting the ATr that's about all I can do on my own. And you are correct, I no longer contact those authorities - though I used to, regularly. I got bored with the standard letters, evasions and no-replies. Don't forget that a lot of people in those authorities also read these forum posts, so the message is getting through.

"Geoff......sorry,but it is the right question for me to ask....I only want to know how much fish they NEED to survive.."

I haven't a clue. The Otter Trust could tell you if you can find any of them. I once visited the Otter Trust (in the 70s!) and they were tossing each otter a couple of sprats. They may have fed them twice a day, I don't know. I do remember the keeper telling me that it was all very unnatural though, sea fish as food, regular feeding times, caged etc.

Just back from a delightful but blank session on the kennet. Nice to be back on the river.

 

[tigger]

MMmm, how many fish does a pike eat to survive or a chub or any fish for that matter. All fish eat fish of one size or another including their own eggs. There's no bigger predator of fish than fish themselves, appart from us...the human plonkers who just seem to beam in a a bird or small mammal that actually needs fish to eat to live. The main reason fish stocks decrease is due to water conditions, pollution etc not some birds or mammals. The old witch hunt over and over....does my F***in yed in !

 

[Steve Spiller]

Too right they are reading it Geoff, but what response have we had?

Nothing..........

Perhaps the stories of an E.A 'keep it shtum' and say nothing is true?

Someone needs to grow some balls and stand up! And tell us the truth!

I'm not holding my breath though........

 

[cg74]

Geoff, you missed the opportunity to put the do-gooding otter keeper straight, it is perfectly natural for European otters to reside in the sea, therefore eat sea fish, you slipped up there....

I never missed my chance to put a keeper straight at Cotswold Wildlife Park last summer when he started bleeting on about how wonderful it was that otters were now wide spread through out the Thames valley and how he'd like to let his caged specimens go free.

My simple retort went along the lines of; when you do that cos they're Asian otters if they cross breed with our indigenous ones they will no longer be a protected and will be classified as vermin, same as mink, bang bang goes the 12 bore.
The jobs worth numpty wasn't best amused.

 

[Steve Spiller]

Sorry Tigger you aint got a clue!

The main reason fish stocks decrease is due to water conditions, pollution etc not some birds or mammals. The old witch hunt over and over....does my F***in yed in !

Cormorants are feasting on inland waters because 'we' overfished the seas!

They've moved inland because the sea is empty!

The beautiful Halcyon River is about four miles from my doorstep

Ignorance and apathy does my F***in yed in!

 

[cg74]

I'd say abstraction, pollution, habitat destruction, invasive alien species, predation, people thieving fish, global warming, over fishing (on and off shore)...... the list is endless

And it all does my F***in yed in!


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Still don't know how much a Cormorant eats, any thoughts and Geoff, too much, ain't really a good enough answer, before you say it.

 

[the indifferent crucian]

Just a second chaps.

It's my understanding that the sea and its fish stocks have nothing to do with out cormorant problem.


I am told that the marine cormorants are in decline and reduced fish stocks play a substantial part in this, however the cormorants that have invaded our waters are NOT marine cormorants.


I am told that they are inland cormorants, raised on European lakes for thousands of years, practically a separate sub-species, that have recently discovered our islands.

Now that we are aware of this it has been possible to obtain a licence to destroy these inland cormorants, whilst the marine cormorant remains a protected species.


Now I claim no expertise in this, so if any of you know different please speak up, but it does explain why we are allowed to take some out from what is otherwise a protected species.

 

[geoffmaynard]

When I was researching this about the time of the Moran Committee, I was told of two sub-species of cormorants. One lot were the originals who were sea-birds come inland about 1980 and the other lot, as IC says, more recently arrived, from inland asian lakes. For 'lakes' you can also read the vast inland seas. This last group can also be assumed to be birds driven West as their local supplies of food were wiped out. so the same cause has them arriving, they come looking for food. Once they find it, they eat it. If that source turns out to be a weak supply, they will decimate it first and then move on to places with richer pickings.

 

[the indifferent crucian]

So the Eastern Europeans have eaten all their own fish, thus driving their inland cormorants West to us in search of food.
Just as the Eastern Europeans turn up to join in and eat any od our fish their birds miss?

It's a pincer movement, it's a conspiracy...send a gun boat!

 

[Cakey]

and what about bears ?

 

[cg74]

So the Eastern Europeans have eaten all their own fish, thus driving their inland cormorants West to us in search of food.
Just as the Eastern Europeans turn up to join in and eat any od our fish their birds miss?

It's a pincer movement, it's a conspiracy...send a gun boat!

Reads like a near perfect appraisal of the situation, IMHO.

 

[Tee-Cee]

I suggest the argument needs widening...will Arsenal supporters die out over the next few seasons as the team fade away.......

and my wife suggest I'm the last of a kind.....spending too much time polishing the rods(or was that singular?)

 

[tigger]

Sorry Tigger you aint got a clue!

Obviously, I disagree with that statmant but I'll keep it zipped so not to offend

 

[Cakey]

I think we shoul cull/kill kingfishers they are photographed all the time with fish in their gobs .

---------- Post added at 13:41 ---------- Previous post was at 13:38 ----------

cant see mr 40lb pike being happy with a minnow once a year better dump them too
oh and theres them other ones

 

[keora]

Here's a summary of a report on cormorant food consumption by three scientists:

1.Great cormorants Phalacrocorax carbo, Linnaeus are large piscivorous birds which occur in Asia, Australia, Africa, Europe and North America. Their European breeding population has increased by at least 15% per annum over the last 15 years, reaching a total of c. 200 000 pairs in the late 1990s. There are concerns that this increase is adversely affecting freshwater fish populations throughout Europe, but real assessment requires a detailed knowledge of cormorant food requirements.

2. The daily food intake (DFI) of great cormorants has been measured during the breeding season, but little is known about DFI in winter when these poorly insulated birds experience consistently low temperatures. DFI is likely to vary widely according to abiotic and biotic conditions, making predictions about impact particularly difficult.

3. We modelled DFI for great cormorants wintering at Loch Leven, Scotland, using behavioural data recorded via radio-tracking of free-ranging individuals, metabolic measurements obtained from captive birds, and published data. DFI was estimated to be 672 g day-1 (predicted maximum range 441-1095 g day-1), values similar to DFI of great cormorants breeding under temperate conditions and of other aquatic bird species.

4. During winter great cormorants at Loch Leven decreased their average dive time and increased dive efficiency (higher proportion of time spent underwater). They nonetheless spent 130 min day-1 in the water and allocated more than a third of their daily energy budget to diving.

5. Synthesis and applications: In view of the need for the sound management of cormorant populations, we present a general bioenergetics model, based on simple behavioural and dietary inputs, that computes an estimate of DFI outside the breeding season for a range environmental conditions and habitats. An interactive computer programme for this model is available (http://www.cepe.c-strasbourg.fr) to help scientists and managers estimate local values for average, minimum and maximum DFI.

The report is entitled "Modelling the Daily Food Requirements of Overwintering Greater Cormorants" and was published in the Journal of Applied Biology in 2003.

The scientists estimate that daily winter food consumption is 672 grams per day per cormorant.

This is about 1.5lbs of food per day per cormorant - it's a lot of fish.

 

[Cakey]

still a lot more killed by polluters and anglers etc everyday

 

[geoffmaynard]

Every day? That's an opinion without back-up facts Cakey. If there is a major pollution incident then there will probably be fatalities from that event but it's not easy to estimate at the best of times, and they don't usually happen every day. Cormorant predation is every day of the year and relatively easy to calculate as Keith's figures above show.

How you come to think anglers are causing fish deaths to exceed those of cormorants is a mystery. As you well know, most fish are returned alive. So you'll have to explain that one to me.

You asked about bears (I don't know why) so try this:

A bear goes into a bar and asks the barman " Can I have a pint of.............................................. bitter please?"
The barman reaches for a glass but asks "Why the long paws?"