Oskaloosa.com

May 2, 2013

Rathbun netting crews strike while the walleyes are hot


The Daily Iowegian

---- — MORAVIA — Rathbun Lake had one of its best walleye netting seasons in years, filling the hatcheries incubators with eggs to spare.

Rathbun Fish Hatchery supervisor Jay Rudacille said hatchery staff are expecting those eggs to start hatching any day now.

“It’s just over three weeks for the first eggs taken, which is a concern, but the hatch is being delayed by the 45-49 degree water, which is on the cool side,” he said. “Typically we get a hatch rate of 70 to 75 percent. The longer it takes the eggs to hatch, the poorer the hatch rate.”

Netting crews hit the water on April 6, and caught the spawn just right.

“We want to be as efficient as possible with our netting crews and this year we nailed it,” Rudacille said. “Our netting operations caught the spawn on the upswing, we netted through the peak and some on the downside and we were done.

“It was an excellent season,” he said.

Female walleyes from Rathbun averaged 1.4 quarts of eggs, an increase over the 1.04 quarts per female in 2012, and 1.11 quarts in 2011.

Crews netted 817 females and spawned 450 that provided 631 quarts of eggs. Rudacille estimates that each quart contains 135,000 eggs bringing the egg take total to a little more than 85 million for 2013. They collected 978 males to fertilize the eggs.

Rudacille said at least 30 quarts of eggs will go to Guttenberg after they receive a triple rinsing of water filtered through a 10 micron filter to ensure that no invasive species go along for the ride.

Once the eggs begin to hatch, 38.5 million of the young fry will go back in to Rathbun and 16 million will go to Clear Lake. Other fry will grow in Rathbun’s ponds to larger fingerlings before being stocked.