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Florida or Northern Largemouth?

You can become an expert scale counter — or ask an expert.

By Larry D. Hodge

If you catch a largemouth bass weighing 14 pounds or more, chances are good it has Florida largemouth genes. The Texas state record of 13.5 pounds stood for 37 years, from 1943 until 1980, a pretty good indication that the northern largemouths native to the state don’t grow much beyond 13 pounds.

Only after Florida largemouths were introduced into Texas waters in the 1970s did Texas bass begin to grow bigger than 13 pounds with regularity. It takes a fish of at least 15.2 pounds to make the list of 50 biggest largemouths caught in Texas, and more than half the 423 entries in the Budweiser ShareLunker program top the 13.5-pound mark.

Anglers looking for a way to tell if the big fish they just boated is a Florida or a northern largemouth had better have either a crystal ball or a fish finder capable of performing genetic analysis on board, according to Dijar Lutz-Carrillo, TPWD’s fish geneticist.

“There’s no quick, sure way to differentiate between northern and Florida largemouth bass when looking at them,” Lutz-Carrillo says. Biologists know that the number of scales along a bass’s lateral line (the dark line running the length of its body) is an indicator. Florida bass typically have from 69 to 73 scales and northerns 59 to 67, but there are problems with using this approach. For one thing, the correct scales have to be identified and counted accurately.

In addition to the number of scales along the lateral line, Floridas and northerns also typically differ in the number of rows of scales on their cheeks, the number of scales above and below the lateral line, and the number of rows of scales around the tail. “Summing these counts, you can use the resulting index to categorize the fish to a subspecies group,” Lutz-Carrillo says. However, you can’t be 100 percent positive using this index. One reason is a large number of fish in Texas reservoirs are hybrids of the two subspecies, and scale counts for hybrids commonly fall somewhere between the counts for Floridas and northerns.

If counting tiny, translucent scales isn’t your cup of tea, you’re not alone. Given the complications, Lutz-Carrillo uses DNA analysis to determine the genetic makeup of fish. All three types of largemouths Texas anglers encounter prefer the same general kind of habitat and will attack the same kinds of baits. While it might be interesting for anglers to know if a fish is a northern, Florida or hybrid of the two, the bottom line is: knowing the combination of chromosomes in a fish’s cells isn’t nearly as important to anglers as the adrenaline rush hooking a trophy bass brings.

Thanks to TPWD’s hatchery and stocking programs, the chances of catching a lunker bass are perhaps better in Texas than anywhere else in the world. Only California and Georgia boast state record largemouths bigger than the 18.18-pound Texas record.

For many anglers, knowing how to distinguish among largemouth, smallmouth and Guadalupe bass is of more interest than whether a largemouth is a Florida or a northern. Fortunately, it’s also fairly easy. You can download a printable, illustrated brochure at <www.tpwd.state.tx.us/publications/pwdpubs/bkbass_diagrams.phtml>.

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