Fish Size vs Maximum Pulling Force

Mr Cholmondeley-Corker (PaSC) · Oct 27, 2009

Here's something to think about:

1. What is the maximum pulling force that a fish of a given species and size can generate?

or put another way, what is the maximum breaking strain line that a species of a certain size can break?

For example, if an 8oz roach accelerates at it's maximum then what is the maximum bs line it could break?

Bluenose · Oct 27, 2009

Depends on the size of the current also and (I suppose) the viscosity of the water!

Edit: The force of an object depends on its mass and its acceleration.

So make a guestimate of it's acceleration, multiply this by its mass then you will have the rough force that the fish exerts.

Mr Cholmondeley-Corker (PaSC) · Oct 27, 2009

But, in the case of a fish, it's ability to accelerate depends on it's strength (or it's ability to develop a burst of strength)

Stealph Viper · Oct 27, 2009

Don't forget to include, where the fish is hooked.

If it's in it's lip and it's lip is soft and fragile, it would take less force to widen a hole in the lip enough to allow the hook to drop out.

There's a lot of variables to consider.

Imagine being hooked in the lip, and having to pull free of it by, tearing it from your lip, then imagine trying to rid it from being hooked in your gums.

Mr Cholmondeley-Corker (PaSC) · Oct 27, 2009

Not too many variables SV

F=mA

Where F = Force (Newtons)

m = mass (kilograms)
A= acceleration (m/s^2)

The key to my question is - what level of acceleration can a given fish achieve?

Bluenose · Oct 27, 2009

Varies on the fish too I expect Matty am sure there will be a scientific paper on google somewhere.

Generally speaking the more hydrodynamic the fish the faster I would suspect it can move. It wouldn't surprise me if a smaller (less trendy) species pulls harder pound for pound.

Stealph Viper · Oct 27, 2009

Blimey, you don't make things easy do you.

The bad one · Oct 27, 2009

Someone somewhere did a scale of the maxacceleration speed of coarse fish. Can't remember the speeds, only that pike came out on top!

Bluenose · Oct 27, 2009

There's also a connection with the amount of red and white muscle tissue if I remember right? White better for short bursts, red, better for longer more dogged bursts??? Maybe I dreamt that or made it up. We need some brainy fishery biologist types onboard.

Peter Jacobs · Oct 27, 2009

Stealph Viper said:
Blimey, you don't make things easy do you.

Well, I suppose that you also have to take into account the shape of the body of the fish as well; a torpedo shaped fish (Rainbow Trout) will have less drag around its' body than say a more 'rounded' shape, like a modern day Carp?

Then you might also factor-in the fatigue 'curve' for the study as well, not to mention the varying undulations in the fish's movement?

Too much for me on a Tuesday afternoon . . . pass.

Stealph Viper · Oct 27, 2009

Peter Jacobs said:
Too much for me on a Tuesday afternoon . . . pass.

I agree, i think i would rather yank out my last Pickle Stabber tooth with rusty pliers than wrap my head round the maths of this one.

Jeff Woodhouse · Oct 27, 2009

Mr. Cholmondeley-Corker (PaSC) said:
if an 8oz roach accelerates at it's maximum then what is the maximum bs line it could break?

Did it have porridge for breakfast?

Bluenose · Oct 27, 2009

The maths isn't that difficult Steph, I think actual accurate data of acceleration is the sticking point, as it is this (along with the mass of the fish) which gives us the actual force it can apply.

I wonder if there is a (near) linear relationship (for fish of the same species) between a fish's mass and it's acceleration?

ie If bigger pike accelerate faster than little pike is this difference proportional to their size?

I take it your not too busy today Matt?

Peter Jacobs · Oct 27, 2009

"Did it have porridge for breakfast? "

Don't be silly Jeff, everyone knows that in order to maximise pulling power then one needs at least . . . . . . . . . . . . . . . . .

3 Weatabix for breakfast!

Blimey gov' don't you know nuffink?

Stealph Viper · Oct 27, 2009

Ok, then, god i know this is going to give me a mega headache.

Let's say that the 8oz roach can accelerate from 0mph to 25 mph in 5 seconds, what then would be the Maximum amount of pressure it could apply to say 2lb breaking strain as a hook length.

I have no idea what so ever, i'll leave that up to the Boffens :wh

Bluenose · Oct 27, 2009

1. convert mph to m/s (metres per second)
2. acc'n is the velocity change in 5 seconds
3. Take said acc'n and multiply it by fish's mass (in Kg) to find force
4. Convert bs of line to newtons
5. If 3 is bigger than 4 then yes it will break.

Stealph Viper · Oct 27, 2009

Well, that's cleared that up then.

Bluenose · Oct 27, 2009

so (changing your numbers to make them easier) say your fish accelerates from 0 to 10m/s in 2 seconds

divide the change in velocity (0-10, so change is 10) by the time taken (2s) the acc'n is 5 metres per second squared (just say 5)

say it's mass is 0.25Kg

mass x accn = 0.25 x 5 = 1.25N

convert your line strength from lbs or Kgs to Newtons, Bobs your auntie

Ray Roberts · Oct 27, 2009

As we hook them in the head and not the tail, the angle at which they pull constantly changes and the fish would usualy kite to the left or right, once it's head is pointed back towards you it's not pulling at all, unless it can swim backwards.

Stealph Viper · Oct 27, 2009

I was right, my head does hurt now.

Fish Size vs Maximum Pulling Force

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