ESTIMATING FISH WEIGHTS
In the last issue of Ohio Smallmouth News we passed along some information on how to estimate the weights of smallmouth bass that are caught and released. Our sources were noted anglers Al Agnew of the Missouri Smallmouth Alliance and Dick Bengraff from upstate New York. After the article was published we received some additional information from the Ohio Division of Wildlife, courtesy of Mike Wilkerson who heads up the special regs program for smallmouth bass in 5 Ohio streams. In this article we’ll compare and contrast the three methods for estimating fish weights.
Fish Weights Vary by Body of Water and Time of Year
As you probably know the weight of an individual fish, regardless of species, often varies depending on the body of water it is caught in and the time of year. For example, stream smallmouth bass are leaner (and often meaner) than their lake cousins, while smallies caught during fall/early spring are usually heavier than at other times of the year (regardless of the water body). Perhaps this is why so many of us who practice catch & release simply refer to the length of a fish when relating its size. Fact is, an 18-inch smallie (whose weight can vary by _ pound or more depending on the body of water and time of year) is a quality fish that we all would like to catch on a regular basis!
Check Out the Table
The accompanying table compares three methods of estimating the weight of smallmouth bass no matter where they are caught. As a general rule, use Method A or Method B for stream-caught fish, and Method C for smallies caught from larger flows or lakes.
In comparing the methods directly, a 15-inch smallmouth caught from a stream (a 7-year old fish in Ohio) should weigh from 1 _ to 1 3/4 pounds (Methods A or B). However, the same 15-incher caught in Lake Erie would weigh over 2 pounds (Method C) and be only half as old as its river cousin (3 to 4 years of age). One minor difference between the two stream estimates, is that the Ohio data (Method A) rounds the ‘tweener’ sized fish to the nearest whole inch, so a 15-inch fish is slightly heavier than its Ozark stream counterpart (Method B). Finally, always keep in mind that the weights of very large smallies (20+ inches) are highly variable, especially stream specimens. Smallies in the ‘twenty-plus’ range are the oldest fish in a system and often lose weight as they grow older.
Of course, rather than relying on estimates such as these, you could carefully weigh the fish that you catch on an accurate scale before releasing them. Another option would be to simply ignore these estimates and use the ‘heavy thumb’ approach employed by many TV fishing personalities: “OH SON, what a big bass! Probably weighs 4, 5, maybe even 8 or 10 pounds!”
This article was intended to provide some helpful and interesting information for anglers who practice C&R for smallmouth bass. Obviously, large specimens of smallies are not abundant in Ohio streams and despite the notoriety that Lake Erie has received, experts suggest that its smallmouth bass fishery, particularly for trophy fish, is feeling the effects of increased angling pressure. Clearly, all Ohio waters would benefit from increased protection for these great fish from conservation-oriented anglers and agencies.
PRACTICE CPR: CATCH, PHOTOGRAPH, RELEASE!
FREE THE FIGHTER!
METHODS FOR ESTIMATING SMALLMOUTH BASS WEIGHTS
|Method A||Method B||Method C|
|Source:||Ohio Stream Sampling 1996- -99
(Ohio division of Wildlife)
|Missouri Ozark Smallies
(Courtesy Al Agnew)
|Comments:||Average weights calculated for all fish within that inch range.||Estimates based on years of evaluating Ozark stream smallies.||Accurate for most northern lakes, and large rivers. (LxLxL/1600)|
|Length||Average Weight (0.0lbs.)|
Note: The weights of smallmouth bass over 20 inches in length are highly variable (particularly stream-caught fish)