What do fish feed on?

[jacques]

Might seem like a daft question but just how do the fish in a river like the Tees survive.
Summer time from say Broken scar down to the barrage its heaving with the current years coarse fish fry and last years three inch silvers. Plus the larger fish and lots of them.
Theres is in reality considering the length of water very little fishing activity. What there is is fairly concentrated to easy access points. So in most parts theres no feed going in from anglers.
Back 50 odd years ago the river say at Croft, Nesham, Middleton one row would see a fly hatch most days of the entire year. Fish would always be topping in your swim. So apart from the maggots thrown in by the considerable number of anglers the fish were fly feeding.
These days you rarely see a rising fish. Theres very little for them to rise to.Hence the now the total lack of one abundant fly feeding birds.
Yet fish at night and the bats hitting your line drive you mad. So there are flies about.
As l say just what keeps a 4lb chub going?
Are they like big trout and feed mainly on smaller fish?

[andy76]

Small fish
Shrimp
Water snails
Flies
Leech
Anglers bait
Midge bloodworm
At night bigger moths and flies
Corixa
Water beetles

[iffy]

where has all the fly life gone ??

[blacktasker steve]

Oct 21, 2019 8:49:53 GMT iffy said:

where has all the fly life gone ??

brexit!

[samvimes]

Riverine invertebrate life has been in decline for years on our local rivers. It offers a reasonable explanation for some of the woes of the rivers. There are a few theories as to why this decline may have occurred, the prime candidate being the use of agricultural pesticides.

[dunsmuir]

Very interesting question. There will be a fair amount of terrestrial stuff like worms, slugs and snails gets washed into the river, I always assume. And now there are so many American crayfish they must be a decent new food source too when younger, as well as added competition when full grown, of course.

And I often wonder what mid Tees pike eat in winter when all the silver fish have migrated downriver? Just the odd dead or dying fish once in a while, perhaps.

[samvimes]

Oct 21, 2019 16:17:40 GMT dunsmuir said:

Very interesting question. There will be a fair amount of terrestrial stuff like worms, slugs and snails gets washed into the river, I always assume. And now there are so many American crayfish they must be a decent new food source too when younger, as well as added competition when full grown, of course.

And I often wonder what mid Tees pike eat in winter when all the silver fish have migrated downriver? Just the odd dead or dying fish once in a while, perhaps.Not

Not knowing the Tees well enough, I couldn't say for definite, but do the majority not simply follow the food source? That's what happens in the case of most migrating prey.

In the case of pike, it's certainly what used to happen on the river Hull. Roach and bream would move downstream, or into more sheltered feeder streams, in the winter. The pike werenever far behind.

[Marc]

Very good question. fish dont feed as much during colder months and probably not wanting move around much either. The river floods more during winter so My guess would be inside bank for slugs and worms as already said. I also think specimens dont move we much on tees as to other rivers I fish. The tees is fairly constant in depth through out middle section so I think the fish dont find deep water and stay close to summer homes. I've had chub and pike in shallows throughout the winter whereas I struggle in them sort of depths on other rivers.

[jacques]

Its something I've wondered about for years now.

Now back in the still water rainbow trout fishing days it was dead easy. Well on waters that contained invertebrate lif
Say Kipling Lake. Early on and throughout the year the resident feeding fish would contain bloodworm and the buzzer larvae as they rose to the surface to hatch and daphnia. Scaling they would contain bloodworm and stickle backs. And terrestrial flies of the season.  Such things were easy to find out as you killed them and spooned the stomach.
River Coarse fish are much more difficult.
In regular fished locations( very few and small in area locally) they must eat a fair bit of anglers feed.
Natural stuff in the form of wind blown terrestrials are small in number(never see many rising fish these days).
Worms and slugs only in flood times.
Signal Crayfish, ok a population in the mid Tees(Barnard castle to Broken Scar) 
Not seen any below Darlington,
Minnows( main form of food for larger fish) are getting fewer as the years go by below Darlington.
Midge pupa, very small 2to4MM but huge concentrations and possibly what keeps the huge population of silvers going. Possible algae growing on the river bottom. 
My guess is the bulk of larger fish eat the smaller ones.
I've put a fine mesh sieve through the lower parts of the river for years now during summer. Midge pupa, and tiny fish are what comes out.