Iowa’s Winter Trout Spawn
Iowa Department of Natural Resources 01.15.13
The scene is a trout angler’s dream come true. Or nightmare of the highest order. All around this corner of the Manchester trout hatchery, 2-pound, 3-pound…7 and 8-pound rainbow trout splash in holding tanks. Glistening, colorful…but with no room to flip a fly or redworm.
“We’re spawning rainbow trout today,” explains Randy Mack, DNR hatchery technician, as he and two co-workers wrestle 40 female trout (the big ones) and a similar number of smaller males inside the Manchester hatchery.
Longtime hatchery technician Kenny Linderwell ‘trays’ the fertilized eggs and sets them into place along the wall. A constant flow of 52 degree water washes over them for about 30 days. The water quantity and quality here have meant a trout hatchery has been on the premises for more than a century.
“We normally spawn enough to produce about 250,000 catchable-sized rainbow trout,” explains Mack. “In the wild, rainbow trout in Iowa reproduce very poorly. We spawn them here and raise them for a year and a half, until they are ready to stock.”
At some point in 2014, these now fertilized eggs will be half-pound rainbow trout, released into about 50 northeast Iowa streams or – increasingly – into urban lakes around Iowa.
Selective breeding over the years has produced a trout timetable. In October, brook trout are ready to give up their eggs. Iowa’s only native trout, they are spawned streamside on South Pine Creek in Winneshiek County. Eggs are brought back to the hatchery to hatch and grow. As they are stocked, they do better in certain streams and overall, are harder to catch than the angler friendly Shasta strain rainbow trout. About 50,000 brookies are stocked each year.
By November, brown trout are spawned. Brood trout are brought from French Creek to the hatchery. They will be raised until fingerling sized, then released to grow wild in several dozen stretches of streams throughout northeast Iowa, supplementing earlier generations of brown trout.
Through December and January, rainbow trout—the backbone of Iowa’s program—are ready to spawn. Once a week, crews check outdoor raceways for ripe female brood stock. Back inside, they firmly massage slimy trout bellies to produce a steady stream of golden eggs, to be fertilized, trayed and hatched.
The eggs hatch into sac fry and are switched to indoor raceways in the hatchery. As they consume their yolks, they swim up and learn to feed on commercial pellets; until loaded for the truck ride to a nearby stream. From there, they fend for themselves…or go home in the coolers of 40,000 plus trout anglers.
That number has grown over the years. First sold in 1962, fewer than 22,000 trout stamps were out there in 1970. The number rose slowly and, in 2010, first topped 40,000. Over 43,000 were sold in 2011; boosted in large part by late fall to early spring urban trout stockings.
That cold weather stocking program, rose from just three urban ponds 25 years ago to 16 quarries, ponds and small lakes this winter, brings trout to city anglers. They can fish locally, and if the urge strikes….use that good-for-the-year trout fee to head to northeast Iowa in the spring, summer or fall. In the meantime, several thousand people who might never have fished for—or tasted—trout are hooked.