A Fish in Swinsto

[Ian P]

On a trip through Swinsto today, I was “shocked” to see a fish swimming towards me on the “long crawl”. It was located about 30m in from the bottom of the first pitch.
It was in a shallow section of streamway with no pools.
The fish was about 100mm (4inch) and swam straight between my legs. I have named him “Bob”.

 

[thehungrytroglobite]

@BigTom

 

[PeteHall]

How the hell did it get there?!?

It surely can't have come from downstream, but I can't see how it could have got in from upstream either!

A PhD in that for someone?

 

[ChrisB]

Maybe a batch of fish eggs were washed in from upstream, and the first to hatch cannibalised the rest?

 

[PeteHall]

Perhaps it's obvious to those that know, but how would fish eggs end up all the way up there to wash in?
Is there a swimable route up the hill from anywhere? All the underground rivers have significant pitches and I'm not aware of a surface stream...

 

[Cantclimbtom]

Maybe a batch of fish eggs were washed in from upstream, and the first to hatch cannibalised the rest?

The sole survivor?

 

[mikem]

Has been suggested that fish eggs get stuck to waterbirds and transported upstream that way (the same could apply to cavers' clothing, as it already appears to be cave adapted, although often there will be too long between trips for eggs to survive)

 

[Pitlamp]

For the best answer to this conundrum, consult the writings of Graham Proudlove. (His 50 Short Passages book gives valuable detail on this in a very readable way.)

Trout are not uncommon in upland Dales caves (they're sometimes reported in Long Churn and the Penyghent canal for example). They're not spotted as often as they might be, because the water is usually very peat stained but at the moment the water in Dales cave streamways is pretty clear, so the fish are more noticeable.

Well done for getting a picture or two.

They're not cave "adapted" in the evolutionary sense; when trout enter caves they gradually lose pigment so they look very pale. But if they're brought out to daylight they recover their pigment again. They're also not blind, as is often thought. I don't think we have any true cave fishes in the UK.

If Graham spots this topic he can give a far better explanation than I can (and may correct some of the above).

 

[mrodoc]

I have always wondered how the eels get into the lake in Pridhamsleigh Cavern.

 

[mikem]

Eels can travel overground to get around obstacles in the river, so underground no problem either!

 

[kay]

They're not cave "adapted" in the evolutionary sense; when trout enter caves they gradually lose pigment so they look very pale. But if they're brought out to daylight they recover their pigment again.

That makes sense. As a child fishing for gobies in the rock pools of N Devon, I was fascinated by the way the changed colour when I put them into my red or yellow bucket, from dark coloured in the rock pool to pale sand colour once in the bucket.

 

[Lankyman]

The sole survivor?

He obviously came up a gill

 

[Pitlamp]

That makes sense. As a child fishing for gobies in the rock pools of N Devon, I was fascinated by the way the changed colour when I put them into my red or yellow bucket, from dark coloured in the rock pool to pale sand colour once in the bucket.

Here's one I photographed a long way into Malham Cove Rising a while back. Definitely paler than when in a surface stream

 

[Andy C]

He obviously came up a gill

A perched aquifer?

 

[Lankyman]

A perched aquifer?

That's a brill answer

 

[Pitlamp]

You lot get worse!

 

[mikem]

Some fish can change the extent of different pigments in their skin to help blend in with the background

 

[wellyjen]

It surely can't have come from downstream,

Not unless someone rigged Swinsto, rather than doing it as a pull through. Since Petzl shrinkflated the size of their jammers, fish prusikking has become much more practical.

 

[Emsy]

Not unless someone rigged Swinsto, rather than doing it as a pull through. Since Petzl shrinkflated the size of their jammers, fish prusikking has become much more practical.

Cod it be possible for someone to generate an AI image out of that? It would be turtley hilarious.

 

[Cantclimbtom]

I was going to post a comment that if you tried it you'd flounder, then I felt guilty (for starting the silliness) and I'd be continuing to derail an interesting topic complete with pictures of cave fish! So in a rare event of me not actually being daft , I thought best leave it to more serious comments