blue or slate-gray above and light below; no dark spots that are characteristic of channel cat; 30-35 rays in anal fin; deeply forked tail
lower reaches of Mississippi and Missouri Rivers in Iowa
frogs, insects, crayfish, worms, host of other living and dead material
101 lbs., 53", Missouri River, Mills County, June 2004, Mike Rush of Bellevue, NE
Blue catfish, not to be confused with the "blue" color phase of the male channel catfish, is indigenous to the southern United States and is rarely found in the lower reaches of the Mississippi River in Iowa. Primarily a "big river" fish species, no specimens have been collected from any of the interior streams, although this fish might very well inhabit the lower Des Moines River. It has been reported in the lower reaches of the Missouri River in Mills and Fremont counties and has been collected in Lake Manawa. Blue catfish were stocked in Big Creek Lake in Polk County in l972, but no returns were reported.
Color of blue catfish, as its name implies, is blue or slate-gray above and light below. The body has no dark spots that are characteristic of channel catfish. The upper jaw protrudes slightly beyond the lower, and the head is prominently convex. The anal fin is very long, and its basal length is about one-third the standard length of the fish. Blue catfish are easily distinguished from the channel catfish by the number of rays in the anal fin, channel catfish having 24 to 29 rays -blue catfish from 30 to 35. The tail is deeply forked and the eyes are small. The air bladder has three lobes or parts, an anterior pair joined side by side and the smaller third lobe is placed behind.
Blue catfish spawn in June and early July when the water temperatures are 70 to 75 degrees F. They construct nests similar to those of channel catfish. The young attain a length of from 2 1/2 to 4 inches at the end of the first growing season. Adults are among our largest freshwater fishes and specimens weighing nearly 100 pounds have been taken from the lower reaches of the Missouri River. While fish of this size are rare, adults weighing up to 20 or 25 pounds are quite common.
The range of natural foods consumed by blue catfish is indeed very wide. They live principally upon aquatic insects and their larvae, crayfish, worms, frogs, small fresh-water mussels, fish, and a host of other living and dead material. Like channel catfish, they are omnivorous in their feeding and take everything that is available and palatable.