measuring fish

I'm glad you asked that Rockabilly. I always wondered that myself. Just to have an idea of how big they get. Thanks!
 
What about depth? Isn't that just as important? Some fish get VERY deep: discus, silver dollars, some rainbows are even extremely deep bodied.

How is that measured and taken into account?

I wanna know! :)

Roan
 
It varies--and this is precisely the reason inch/gallon rules are so inadequate. I'm sure that fish biologists in tropical regions do in fact have methods for including the depth of the fish--at a guess, it would show up in the calculations. For example, with trout, we take weight and length measurements, and can then use that to calculate the body condition. The condition factor used in this formula vary with species and location--lake versus riverine fish of the same species, lake trout versus rainbow versus walleye. The condition factor used for deep bodied fish would account for the body shape, I'm sure.
 
I think this might help. If you catch a fish and don't have a scale and want to know how much it ways, you take two measurements, length (nose to tip of pinched tail) and circumference of the widest part of the fish (usually stumach area). With those measurements, there is a formula to get the weight of the fish. I think these measurements are also used by people studying fish.
 
I'm a fisherman too. My friends dad has this thing in his living room. Its a fish head and tail attached in the middle by a soft spring, so you can make the fish as big as you want.
My brother has a scale/measuring tape for fishing, the name is "de-liar". I like a good fish story, we always(fisherpeople) try to get that extra inch in there!!:D
 
stingray4540 said:
I think this might help. If you catch a fish and don't have a scale and want to know how much it ways, you take two measurements, length (nose to tip of pinched tail) and circumference of the widest part of the fish (usually stumach area). With those measurements, there is a formula to get the weight of the fish. I think these measurements are also used by people studying fish.
Click to expand...

There are formulas to obtain fish weight based on length alone for estimation purposes. You must have the K-value for the species in question, though.

For instance, if we have an 14" Blue Tilapia, and we know the K-value (.00084), it's a simple matter of plugging the known values into this equation:

W = KL^3
(where W is weight in lbs, and L is length in inches)

Thus
W = (.00084)(2744)

Our 14" Tilapia is estimated at 2.3 lbs.

This method is used mostly for estimating large quantities of fish of a known length to find the rough weight of the group. It's very useful in hatchery setting when calculating the food and oxygen requirements (and waste production) of a large amount of fish.
 
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