What did it weigh?

By Gord Ellis

Question: How can you tell when a fisherman is lying? Answer: His lips are moving. Yes, I know it's an old joke, but it still has the ring of truth to it. Walleye anglers are the worst fibbers, turning a handful of half-pound cigars into stringers of 2-pounders. Following closely are truth-stretching rainbow trout anglers (who like to claim they catch big fish, in massive numbers) and salmon anglers (who are always doing great, no matter how poor the fishing).

Actually, I think few anglers mean to stretch the truth. We just get used to doing it to each other and learn to accept it. Then there is the excitement factor. Due to the widening of our eyeballs, we tend to overestimate the size of the catch. In these days of selective harvest, weight estimates of released fish can be exaggerated beyond belief. A quick guess, and it's back in the water. However, if you want a fair estimate of the weight of a fish before you release it, there are several methods.

You can weigh a live fish on a portable scale, but suspending it by the head can damage internal organs. It's better to weigh it in a net or a wet sack, then weigh the sack and subtract that from the total.

To estimate weight by measurement, you must use a specific formula. All fish are not created equally. This has been taken into consideration. For the first set of formulas, length is always multiplied by itself three times, but the denominator changes with the shape of the fish. Obviously a pike and a bass have different body shapes. Although not as accurate as weighing a fish on a certified scale, these formulas will give a ball-park idea of the weight of your big fish.

Smallmouth bass: length x length x length divided by 1600. This should be close to the actual weight of an average bass. Obviously, however, all bass are not average, and you must take that into consideration. The formula for an 18-inch smallmouth bass would be 18 x 18 x 18 divided by 1600 = 3.64 pounds (multiply by .454 to covert to metric; in this case it's 1.65 kg). Below are formulas for other species.

Pike and muskie: length x length x length divided by 3500. Walleye: length x length x length divided by 2700. Crappie and panfish: length x length x length divided by 1200. Formulas for trout are a bit different. They take girth as a primary consideration of weight. For girth, measure the thickest point of the fish, which is generally in front of the dorsal fin. There are two formulas for trout.

Rainbow trout, lake trout, and salmon: length x girth x girth divided by 800. Brook trout: 1.33 x length x girth x girth divided by 1000. This last formula has been tested against many weighed large brook trout, and I've found it to be very accurate. However, there are others who say this is still too conservative a formula for those really fat specs. You be the judge.