TPWD News Release — Nov. 12, 2007
Fish are aged by counting annual growth rings (annuli) in small ear-bones called otoliths that fish use for balance and hearing.
The official age estimate of 23+ years indicated that the big fish may have been as old as 25. Heart of the Hills researcher Dave Buckmeier said the two years Splash spent in captivity at the Texas Freshwater Fisheries Center in Athens may have been responsible for “fuzzy” growth rings on the outer edges of her otoliths.
“The estimate is 23+ because there were 23 annual rings plus some growth,” Buckmeier said. “Being held in captivity in a stable environment may have affected the formation of annuli. Plus old fish like that tend to be more difficult to age. As fish get older, their growth rate slows, so there is less space between rings.”
The two otoliths, one from each ear, were each about the size of a pencil eraser—or a diamond that would make any bride-to-be swoon. “They were actually pretty small considering Splash weighed 121.5 pounds,” Buckmeier commented. “All North American catfish have small otoliths. A three- to four-pound largemouth bass would have the same size otolith as Splash.”
To prepare an otolith for viewing under a microscope, Buckmeier used a small rotary tool to grind down one side and then polished it with 600-grit wetted sandpaper while holding it with rubber-tipped forceps.
Then he cooked it. Sort of.
“Heating the otolith on a hotplate until it was golden brown intensified the calcium in the rings so they showed up better,” he explained. “Different densities of calcium show up as rings—slower growth rings are denser. In a poor year when a fish gets little food, the distance between the rings is less.”
As for how Splash’s age compares to other fish, Buckmeier said 23 “was not young, but it’s pretty impressive. I’ve aged a blue cat from Tennessee that was in the 110-pound range and was about 19 years old. I also aged a 92-pound state record blue for Virginia at 12 years.”
Buckmeier’s findings confirmed the feeling many people have that there was something special about Splash. “We’ve been seeing that most fish 90 pounds and up tend to be fairly young relative to their size, whereas the older fish tend to be much smaller—blue cats weighing only 8 pounds have been aged at 32,” Buckmeier continued. “It appears that these really big fish are fast growers for some reason. Conditions in the reservoir are part of it, but growth can vary a lot, even in the same system. Perhaps there’s a genetic link, but we don’t know that.”
Is there another Splash swimming around in Lake Texoma waiting to be caught? Maybe, maybe not. “The growth of that one fish is not necessarily typical of Lake Texoma,” Buckmeier said. “But a lot of people around the country are starting to age blue catfish, so the database is growing.”
Bruce Hysmith, TPWD Inland Fisheries biologist whose beat includes Lake Texoma, says interest in fishing for blue catfish was sparked years ago by a striper guide who saw big, umbrella-shaped images on his sonar and wondered what they were. It turned out they were big blue catfish holding in deep water along the river channel. “The bite is from December through February,” Hysmith said. “Kill the engine and drift over the fish without putting out an anchor so as not to disturb them. Use shad for bait. Let it down and wait for a little nibble that feels like a little baitfish jerking. Set the hook and hang on.”
Hysmith said the blue catfishery is still good in Lake Texoma, but fewer people seem to be taking advantage of it. “Bright, sunny days with no wind, when the stripers aren’t biting, is the best time for blues,” he said.
Someday, perhaps 100 years from now, a future generation of anglers and big fish fans will know how Splash fits into the big picture. She may turn out to be one of only a handful of fish of her species ever to attain such size, or she may be proved to have been one of many big blues.
Either way, Splash’s memory will live on in an exhibit at the Texas Freshwater Fisheries Center, where her skeleton will be displayed along with the story of her life. During the two years she was at the center, Splash was the main attraction. “Splash had an amazing impact on visitation to the Texas Freshwater Fisheries Center,” said TFFC director Allen Forshage. “The first year she was on display, our annual visitation increased by more than 43 percent, and Splash was pictured on the front cover of several national magazines.”
The Texas Freshwater Fisheries Center is located 75 miles southeast of Dallas at 5550 F.M. 2495 east of Athens. For more information or directions call (903) 676-2277.
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