Analyze this
Just how do you confirm which cat is which fish?
Years ago, as a fisheries research assistant at Iowa State University, I was given a task of gathering data for a life history table of species of fish in the Missouri River. For weeks, I waded through books, journals and theses to unearth such information as the growth rates of a river redhorse, the ovum diameter of a quillback, and the age at maturity of the sturgeon chub.
But the literature on the life history for one freshwater species seemed distinctly different.
Most information on the mighty blue catfish (Ictalurus furcatus) consisted merely of statements such as: "In 1847, Steve Hansen of St. Louis landed a 145-pound blue cat in the Mississippi River on a trot-line." That's great news for the 1847 Hansen family picnic, but hard biological data, it ain't.
Besides beefy bragging records, one of the few unique pieces of information that keeps turning up on Internet searches is the rumor of scuba divers visiting the walls of dams and seeing catfish "the size of Volkswagens."
Kim Graham, of the Missouri Department of Conservation, Fish and Wildlife Research Center, also noted a lack of data on the blue catfish in the paper "A Review of the Biology and Management of Blue Catfish," and suggested it might be due to the difficulty of sampling large rivers.
Perhap another factor is the difficulty in identification. What if the catfish are only the size of skateboards?
A few years ago, in Pennsylvania Angler and Boater magazine, a ranger reported citing a fisherman for keeping an undersized muskellunge. The angler's excuse was that he thought all the big ones were muskies, and all the small ones were pike.
My inner grad student was appalled by such ignorance. Pike can be identified with certainty in a glance by their horizontal body markings and a rounded caudal fin.
A glance may not be enough to identify the blue catfish.
Recently, I've come to grips with my own ichthyologic inadequacies in that I too may be guilty of catfish size stereotyping: Big catfish are blues; small ones are channel catfish.
Apparently I am not alone.
Keith "Catfish" Sutton, author of "Pro Tactics: Catfish" and three other books on catfishing, e-mailed that it is "often very difficult to distinguish blue cats and channel cats. When I was state fishing records coordinator for Arkansas, we often had people bring in large catfish that might have been either channels or blues ... hoping they were channel cats larger than the current record."
The recent North Carolina record "Barbie Pole Catfish" required a state fisheries biologist to verify it was a channel catfish and not a blue. Sam Eifling wrote the 1971 state record channel catfish was recently abandoned when "a magazine turned up photos showing that is was actually a flathead."
Again, I cringe.
With their protruding lower lip, flathead catfish are easy to identify. But how does one identify a true blue catfish?
Well, they are "blue-ish" in color, right?
Quoth Mr. Sutton: "Coloration is never a good way to judge species because it is so variable."
Pflieger's "Fishes of Missouri" describes blues as "never having dark spots." But it doesn't help us that some channel cats also may lack spots.
"Fishes of Missouri" also lists an anal fin that is straight edged "like a barber's comb."
But I recently returned from a lengthy viewing session of several large catfish at an aquarium in a mega fishing store and none of the anal fins inspired me to tjuz the few remaining hairs on my head.
"In the end," Mr. Sutton punned, "there's only one sure way to tell ... the anal fin rays. The anal fin ray of a channel catfish is 24-29 rays; the anal fin of the blue catfish is 30 or more."
I know what you are thinking. "Geez, this article sure uses the word 'anal' a lot!" And I'll have to agree. Plus, there is growing concern that this article will now appear in the wrong kind of Internet searches. But that leads me to my point: This identification method does not seem fitting for such a magnificent fish.
"Wow! What is it?!"
"I don't know yet. Let me take a peek at its 'nether region.'"
No other great predatory fish has to endure such a personal examination to settle an identity crisis.
The blue catfish is legendary for its tremendous size. According to Graham, of the United States freshwater fishes, only two sturgeon species and the alligator gar are capable of reaching sizes larger than the blue catfish. That's some rare company. A giant channel catfish may reach 30 pounds; blues can top the scales at over 100. Several sources even mention a 300-pound blue caught in the 1800s.
It seems the very least I could do to honor this great fish, if I do happen to catch one, is to properly identify it by, yes, counting anal fin rays. To assist in this slightly embarrassing predicament for both catfish and angler, I try to bring a bit of levity to my boat-side manner and say "turn your head and ... count" and try to console us both that at least latex gloves aren't involved. If questioned by a bystander, I generally resort to some important-sounding fisheries research terms:
"I'm executing a full 'Catfish Anal Fin Evaluation'," I might say. (Or I'll just call it "CAFE" if I don't want the word 'anal' to enter the conversation. Which, come to think of it, is far more likely.)
"Let's see ... 1, 2, 3, 4, 5, 6 ..."
Whap! (Massive tail slap across the face.)
"Son of a ... ! Now, where was I?! 1, 2, 3 ..."
Just doesn't seem right.
Andy Whitcomb, a freelance writer and designer, can be reached through his web site, justkeepreeling.com.
