How many fish do catfish eat in a year?

fishplate42 · Nov 26, 2017

I was reading thecrow's post on the Predator forum about the size of bait and what catfish will eat. It got me wondering. How many fish will, say, a 50lb catfish eat in a year?

At my favourite commercial, they have a lake full of catfish some of which are well over 80lb. They seem to catch them on huge lumps of canned meat, like Spam etc. Would there be enough food 'lost' by anglers to prevent them devouring all the other fish in the lake? There seems to be a lot of catfish in the lake.

Ralph

mikench · Nov 26, 2017

No idea Ralph but it stands to reason that it must be a lot! They do not grow so prodigiously feeding on pond weed!

I will say no more about this species of fish as it would put me off my ......... fishing!

thecrow · Nov 26, 2017

fishplate42 said:
I was reading thecrow's post on the Predator forum about the size of bait and what catfish will eat. It got me wondering. How many fish will, say, a 50lb catfish eat in a year?

At my favourite commercial, they have a lake full of catfish some of which are well over 80lb. They seem to catch them on huge lumps of canned meat, like Spam etc. Would there be enough food 'lost' by anglers to prevent them devouring all the other fish in the lake? There seems to be a lot of catfish in the lake.

Ralph

What other species and sizes are in the lake? I have a feeling I know the water you mention just from the size of wels you mention.

Any predator fish or mammal will only exist in the numbers that the prey species allows, no predator would eat every fish in the lake no more than every lion would eat every wilderbeast, the balance of predator to prey is a constantly changing and very complex subject

As to your original question its impossible to know its like asking how many maggots a roach would eat in a year.

Hugh Bailey · Nov 26, 2017

I read an article about Wels being used to sort out signal crayfish issues in various lakes. A single wels would be introduced - left for a year or so , then removed upon capture. It sounded a very reasonable approach & guess it is nonsense as, for some southern rivers, it could be a real answer.

mikench · Nov 26, 2017

If that worked I would be in favour on an experimental basis and one cat cannot breed! Gosh I might become a fan!

sam vimes · Nov 26, 2017

I couldn't answer the question if I tried. I've never seen figures given for any type of predatory freshwater fish. However, I do wonder if wels aren't quite as predatory in colder northern environments as they might be in warmer, more southerly ones. I'd also wonder whether omnivorous cavengers like wels will be particularly predatory if they can find enough sustenance by other means. Sackfull of spodded pellet and a very easy life, or chase around after a fish that may escape?

mikench · Nov 26, 2017

You make valid points Sam save that I believe cats are ambush predators and lie in wait for their prey to come to them! I don't think they have a great turn of speed! They will no doubt devour all the surplus pellets, boilies, groundbait and discarded dead bits with gusto and little effort! In some locations that lot might be all they need to thrive!

sam vimes · Nov 26, 2017

mikench said:
You make valid points Sam save that I believe cats are ambush predators and lie in wait for their prey to come to them!

Pike are ambush predators, but they have a fair turn of speed. Wels aren't in the same league, but they aren't as sluggish as you might think. Any type of hunting live prey is going to be more active than scavenging.

YouTube

thecrow · Nov 26, 2017

sam vimes said:
Sackfull of spodded pellet and a very easy life, or chase around after a fish that may escape

It might be for that reason that the cats on my local water are always caught by Carp anglers, it could also explain how many waters with Wels in them also sustain a very healthy Carp stock.

tigger · Nov 26, 2017

We have some purpose built lakes nearby where they specialise in exotic species. The wels pool is only stocked with large carp as anything smaller will be eaten by the cats. These cats breed prolifically and they have pools full of kittens. I was talking to a couple lads in their tackle shop who look after the wels a few months back and they told me to put wels into any mixed fishery would be stupid and that eventually the cats will devour everything.
The waters i'm talking about are called Fir tree fisheries in wigan.

markcw · Nov 26, 2017

Tigger, I think it is only the specimen lake at fir tree that has cats and large carp in it, the others are mixed fishery and the match lake/teaching water has barbel in it, I like Fir Tree, a well run fishery that teaches youngsters both on the bank and in the classroom. My club has a few waters with cats in them and they breed regularly, we had a pool dug out and that has been stocked with the large cats and carp from an adjacent pool at the land owners request,
Cats should start hibernating around now so any smaller prey fish in waters should be safe for a coupe of months,

steve2 · Nov 26, 2017

You only have to look at a catfish to realise that it is just a mouth with a tail attached and that mouth needs feeding.

Philip · Nov 26, 2017

fishplate42 said:
How many fish will, say, a 50lb catfish eat in a year?

The anwser is 110.

Based on studies done on the continent the average Wels of between 1m and 2.50m (a range which a 50lb fish should fit into) gains 3-4Kg per year with a conversion rate of about 10%. For river fish.

This means that a 50lb Wels in a river would eat around 40kg a year, lake fish maybe a bit more say a maximum of 50kg a year. If we assume (finger in the air guess) that say 50% of its diet is fish and the average fish it eats is 8oz in size then it would eat 110 fish of that size a year.

Enjoy.:thumbs:

steve2 · Nov 27, 2017

When Catfish were stocked into one of our club waters to help control the numbers of small carp nobody told the catfish to eat them. What happened was they ate the Tench first. It’s now very rare to catch a Tench on this water. It is still overstocked with carp and was netted to remove some of the carp and catfish.
So if you are thinking about stocking catfish to control other species be careful.

fishplate42 · Nov 29, 2017

Thanks for all the repies, I was just wondeing how fisheries heep a balence when there seems to be a large head of catfish in a lake. At Beaver Fishery, they have a catfish lake that seems to keep on producing lots of sizable catfish. I was just wondering what and how much they eat. I know have some idea.

Ralph.

How many fish do catfish eat in a year?

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