MOUNT IDA - Looking down into the clear water in a Lake Ouachita cove, the big fish resembled German U-boats in World War II. They circled the nets like submarines around a freighter.

These were blue catfish, large ones, and they were in their regular habit of cruising the net pens of the Arkansas Game and Fish Commission, where crops of channel catfish in warmer weather and rainbow trout in cool weather are raised.

Food in the form of pellets is fed the penned fish daily, and this is what the wild blue catfish were after. Trouble is, they aren’t bashful about slamming into the floating nets in search of easy eats.

“They are big enough to do real damage to the nets,” said Leonard Dean, who is in charge of the Jim Collins Net Pens on the upper end of Lake Ouachita. “There’s a net up there on the bank that has a big hole torn in it. It costs a lot to repair it.”

When a net is torn open, fish in it escape. That’s not altogether bad, not a total loss, as some of the fish are destined for the lake anyway - but later and at a larger size. Some of the channel catfish are trucked to other waters when they reach the desired “catchable” size.

Dean and other AGFC fisheries workers snare the prowling blue catfish when they can and relocate them at other places, usually in other lakes.

It can be a rodeo.

A 15-pound blue catfish is a handful at the end of a large dip net. A 40-pounder is a double handful or more. And some of these U-boat imitators are in the 100-pound range, Dean said. When they are that big, they are virtually unmanageable as far as trapping and relocating.

The channel catfish inside the nets are produced in AGFC hatcheries then are grown out to catchable size before being released. They start as fingerlings three or four inches long and grow to 12 to 14 inches long. On the average, a net’s crop of channel cats is about 50,000 - a lot of fish, a lot of weight and a lot of feed required.

The net pens are suspended in a deep cove by a square of floating walkways. Work boats make daily visits to the pens with hundreds of pounds of catfish pellets. In the fall, when the fish are large enough, they’ll be released then replaced with small rainbow trout. These also will be grown to catchable size, 11 to 12 inches long, and released in the trout waters of southwest Arkansas.

The AGFC operates three net pen units - one at Lake Ouachita, another at Bull Shoals Lake in north Arkansas and the third at Lake Wilhelmina in western Arkansas. The Jim Collins Net Pens on Ouachita are named for a long-time fisheries biologist, now deceased, with AGFC.