Rotated tail.
Total Length
Squeezed tail.
Total Length
First, place the fish on its side on a flat board with its jaw closed.
For
total length, measure in a straight line from the tip of the snout to the
extreme tip of the tail fin. Rotate OR squeeze the tail so you can determine the
maximum length of the fish.
For
fork length, measure in a straight line from the tip of the snout to the fork of
the tail.
For
curved fork length, measure tracing the contour of the body from the tip of
the upper jaw to the fork of the tail.
For
carcass length, measure the curve from rear edge of gill opening to the front
edge of the caudal keel (the ridge found just before the tail fin).
For
lower jaw fork length, measure from the tip of the lower jaw to the midline of
caudal fin. This measurement is used for billfish such as swordfish.
Measuring Fish
Fish illustrations by Duane Raver.
Fork Length
Caudal Keel
Carcass Length
Gill Opening
Upper Jaw
Curved Fork Length
Tail
Fork
Lower Jaw Fork Length
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