Learning from line bites

[The Flying Tench]

Thanks for helpful comments on how to avoid liners, but my original question is why we don't get many more of them. When you think of a swim buzzing with fish you'd expect to get one every few seconds. It occurs to me that, even in murky water, you don't get many liners on many occasions. Could it be that they can detect the line with their ventrical line (have I got the right word?) or in some other way?

[Vagabond]

What you do get very often, (but only if you fish at very close range can you see it easily) is a slight swaying of the float - not by an actual line bite, but because the line and shot are being displaced sideways by the vortices caused by the fins of feeding fish. Very noticeable with tench.

 

If line bites become frequent, you risk spooking the fish - usually I try to get a feeding area going about two or three feet across and fish at the edges of it rather than smack in the middle. Line bites are fewer if you do that. The further out you fish, the more difficult this is to achieve - fishing just a rod length out give you much better control.

 

Not only that, but you can see the water displacements caused by fish - boils, swirls, clouds of mud and silt etc, so much more easily at close range. If you are lucky you might see the black tails of your target tench as they feed with their heads in the silt - "bouncing" on their heads like a lot of slow-motion Zebedees

[Newt]

johnclarke - the carp 'paylakes' in the US are known to be a bit rough on the fish and have to replace part of their stock each year. The replacements are either 'wild' fish or farm raised but in either case, fish that haven't seen any angling pressure.

 

The usual there is for new fish to give line bites quite often but after 3-4 weeks in an environment where they swim with rigs & lines on a daily basis, the liners almost completely quit.

 

This happens even with most paylakes being quite muddy so what would be almost zero visibility to human eyes.

[The Flying Tench]

That's an interesting piece of evidence, Newt. Would it be a reasonable argument to say that, since liners aren't particularly more frequent when the water is muddy, the way they learn to avoid the lines is probably not by sight (or not only, at least). Fish swim about in the pitch dark, and must have ways of not bumping into things. So the carp in the paylakes learn to avoid the lines by their brains getting more tuned in to whatever mechanisms they use for sensing slight pressure differences in the water?

 

I'm only spelling out what I think you're implying anyway. I think I'm convinced, but what we don't know is whether the detection of anglers' lines in this way results in greater wariness by the fish.

[Newt]

I'm really not sure how they spot (and avoid) the line. Nor can I even begin to say for sure if the line makes them wary. Wish I knew answers to both.

 

The paylake thing seems to be pretty universal though. I rarely fish them myself (aversion to puddles and crowds) but paylakers on a US angling forum seem to be in agreement that the new fish hit lines and that after a while any line bumps become very rare even when the water is almost muddy enough to walk on and certainly too clouded for human eyes to see anything.

 

Maybe one of the fishery biologist folks could tell us if fish see further into the IR or UV ends of the spectrum and if that makes the cloudy water less of an issue to them.

 

Or maybe it is a feature of their lateral line or some other structure. If so, no idea how since my understanding of the lateral line is that it is a vibration sensor and hopefully we don't have our lines vibrating.

 

[ 14. June 2004, 11:12 PM: Message edited by: Newt ]

[ginger]

It is probably completely irrelevant to this topic but make up your own mind. I was fishing on Saturday evening until duskish and the bats were out, skimming over the surface and wheeling around. There were 3-4 directly in front of me and several times they collisded with the line between my rod tip and the water. I was under the impression that the bat's radar was highly sophisticated but it struck me as odd that it happened more than once, it was almost as though they trying to 'catch' the line. Perhaps fish are as 'blind as bats' or maybe they too have sonar of a sort that needs a bit more development!

[The Flying Tench]

As I understand it, bats send out high frequency sound waves, and their brains process the echoes to avoid them bumping into things. It doesn't surprise me that a fine line doesn't reflect enough of an echo to stop them bumping into it, though strangely I've never had a bat bump into my line.

 

Now a fishes' lateral line system responds slightly differently. (In case you think I'm knowledgeable I'd better admit I've just looked this up.) The nearest equivalent for a human apparently is feeling air moving past your face when someone waves their hand past you, but of course a fish's sensitivity in water is hugely greater, and they are probably constantly aware of subtle pressure differences. It tells them, for example of a nearby predator or, conversely, of food. Though this sense is thought to be 'deafened', for example, in fast running water. The question is, is the lateral line system sensitive enough to pick up the presence of a fishing line? Based partly on Vagabond's comments about the vortices from a fish's fins moving the line, my vote would be 'yes'. The fact that the line moves, ie the water doesn't just flow round it but experiences it as resistance, means it could well be detectable in still water - though that's simply one person's guess, as you appreciate.