Girth is critical to determining weight without killing fish
The formula used to estimate the live weight of a red drum, as stipulated by the South Carolina Department of Natural Resources, is pretty straightforward. All you have to do is measure the girth at the fattest part of the fish and the length of the fish from the tip of the bottom jaw to the V of the fanned tail, and then plug that information into this forumla:
(Girth x Girth) x Length/800
The resulting number is the estimated weight.
So, let’s apply the formula to a fish measuring 37 inches long, with a girth of 19 inches.
19 X 19 equals 361.
Now, multiply that by 37 inches (the length), and the result is 13,357.
Divide that by 800, and the final number is 16.69625 pounds.