Fisherpersons who practice catch-and-release fishing often want to know the weights of the fish they release. Because reliable scales for weighing the fish before release usually are not practical, you can use a formula based on the fish's length to estimate its weight. Calculate length and weight for salmon using the Sturdy Scale before you release your catch to get an idea of the size of the fish you let get away.
Measure the salmon fish with the tape measure from the tip of the fish's nose to the middle of the fish's tail where it curves inward. Measure the girth of the salmon immediately in front of the fish's dorsal fin.
Square the girth measurement. Multiply the length by 1.3333.
Multiply both products from the previous step together and divide the product by 800 to get a weight estimate.
Edward Sturdy created this weight scale and equation based on salmon fish from the Vosso river system in Norway.