How fast does a bass grow?

Capt. Ben Hayes, a guide of Chickamauga Lake, with an 8 lb. largemouth bass. Growth rates vary greatly, but based on research by fisheries biologists, this fish is probably between eight and 10 years old. (Photo: Richard Simms)

How fast does a bass grow? That's a question a number of readers asked after seeing the photo of inch-long young-of-the-year largemouths netted by state biologists from Alabama's Lake Guntersville in The Fishing Wire a few weeks back.

The answer, according to James McHugh, former District IV Fisheries Supervisor for the Alabama Department of Conservation and Natural Resources, varies by lake and by weather conditions.

Fish can be aged by examining scales or various bones. Hard body parts grow as the fish grows, adding annual rings similar to the rings in trees. Scale ring counts, however, are not especially accurate. Biologists say the most accurate aging method is by using the otolith, a free-floating bone in the inner ear of fish. However bass must be sacrificed (killed) to retrieve the otolith. Biologists say that growth can vary greatly between individuals, even within a single lake, depending on the abundance and availability of baitfish.

According to McHugh, the average 5-year-old bass in Alabama reservoirs will be 17.2 inches long. However he adds that bass of the same age, in the same population, can have quite different growth rates. There is often a range of four or five inches between the largest and smallest individuals of the same age. For instance, he says in Alabama the average three-year-old largemouth bass is 13.3 inches long, however some will be as small as 11 inches and others as large as 15 inches.

He says that growth in length is greatest in the first year and decreases each year thereafter. Old fish increase in length very little from year to year, but do continue to add weight.

Mike Jolley, Region III Fisheries Biologist for the Tennessee Wildlife Resources Agency says in Chickamauga Lake their latest research (conducted in 2014) showed the average 5-year-old largemouth bass was 16.42 inches long. He said, however, that of all the 5-year-old largemouth aged in that study (67), they ranged from 12.95 up to 19.84 inches.

"It takes a largemouth bass in Chickamauga about four years, on average, to get to the legal creel size of 15 inches," said Jolley. "In our studies we didn’t record any [bass] more than 12 years old, which was the age of the state record bass Gabe Keen caught in 2015."

In other words, those four-to-five pound tournament winners everybody is always hoping for take well over five years to produce in most southern lakes. (Fish in northern lakes grow much slower due to slowed metabolism for half the year, and Florida strain largemouths stocked in some California lakes grow much faster, the result of stuffing themselves with stocked trout.)

Bottom line is that it takes time and good habitat to produce trophy bass.

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