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Hey I found these in an article and thought I'd share... I seen the Bass one before but not the others.

What is the formula for determining the weight of a fish based on its size?

The rule of thumb for fish weights of various body types are:

Pike (length X length X length) divided by 3500

Walleye (length X length X length) divided by 2700

Bass (length X length X length) divided by 1600

Bluegill (length X length X length) divided by 1200

Another generalized formula is:

(girth X girth X length) divided by 800

All of these will result in reasonable approximations.
 

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Haven't checked the formulas for all the species but it seems to me the number for bass gives an estimate that is just a tad high. Bass lengths and weights that I have recorded this year come out about right if I use a divisor of 1750 rather than 1600.

It's probably not possible to be real precise, though, the length to weight ratio of fish might even vary a little from one body of water to another.
 

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Walking Eagle said:
Haven't checked the formulas for all the species but it seems to me the number for bass gives an estimate that is just a tad high. Bass lengths and weights that I have recorded this year come out about right if I use a divisor of 1750 rather than 1600.

It's probably not possible to be real precise, though, the length to weight ratio of fish might even vary a little from one body of water to another.
So you are saying if I am catch and release use 1600, but if I'm bringing them home and others witnessing use 1750? :p
 

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ePiC said:
So you are saying if I am catch and release use 1600, but if I'm bringing them home and others witnessing use 1750? :p
You catch on real fast. ;D
 

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most of those are just based on lenght and fish varry quite abit in girth. arnt there some formulas that take the girth into account especialy for bass?
 

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The formulas I've tried on weighed fish never actually matched up with the scale. The formulas would always add at least two pounds over the actual weight of the fish.
 

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roadkill said:
most of those are just based on lenght and fish varry quite abit in girth. arnt there some formulas that take the girth into account especialy for bass?
fwiw, the link I posted above does include a girth measurement...
 

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work2fish said:
roadkill said:
most of those are just based on lenght and fish varry quite abit in girth. arnt there some formulas that take the girth into account especialy for bass?
fwiw, the link I posted above does include a girth measurement...
that's why i said "most", the one that does include girth was listed as "generalized" i was hopeing for some species specific formulas
 
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