ROLLING FORK — Men and machines keeping the catfish alive at Carter Brothers Farms are using a little less energy these days in a process that’s helped the fish farm’s bottom line.

Maintaining oxygen supply to more than 3,500 fish per acre swimming in the farm’s 32 ponds became a computer-controlled process in March, when the solar panels were installed on aerators.

While they keep batteries on the buoys charged, radio signals sent every 4 minutes from a central repeater station to a main processor adjust how much energy is used by each buoy.

For supervisor John Abney, it’s time and money saved daily.

“It used to take four to five checks and 2 1/2 hours by our guys to turn the aerators off,” he said. “They’d have to individually read them. In the summer, when the oxygen drops, we’d lose fish.”

The 360-acre catfish and row crops farm off U.S. 61 won a $29,958 grant from the U.S. Department of Agriculture for the down payment on the system. It was one of 15 awards to Mississippi businesses and individuals from more than $27 million in grants and guaranteed loans this year from the agency’s Rural Energy for America Program.

The system lets Abney or either of two farm hands check oxygen levels, water temperature and the voltage — the latter of which has coupled with market forces to cut power bills. From March through October, the company paid $34,318.04 in utility bills — down from $108,526.78 for the same time span a year ago, company officials said.

“The system is a good investment and it will keep our energy costs down,” said president James R. Carter, also a member of the Twin County Electric Power Association board of directors.

Higher prices for farm-raised catfish this year — currently $1.25 a pound, Abney said — has meant more of the whiskered delicacy swimming in the ponds compared to last year, which has kept aerators busy during the day but leveled out to about 12.5 volts per buoy. At night, they’re switched off, which made scorching weeks in August and September easier to bear.

“It’s saving us some hours at night, and just one guy to work at night,” Abney said. “It’s easier to sit in here and watch DVDs and just watch the laptop.”