Northern Pike eggs now in Spirit Lake hatchery

PHOTOS BY GARRY BRANDENBURG — A fish with a lot of fight, the Northern Pike, (Esox lucius), will grow from its tiny egg hatchling size of late March to maybe six to eight inches long by this fall. By the end of their third year, a northern pike may be 17 to 23 inches long. This species of fish, if it has a long life and can survive to age 12, may be 46 inches long. In today's image, Catherine Brandenburg, now living in Fort Walton Beach, Fla. with husband Craig, hooked a northern at Kettle Falls Lodge in Ontario, Canada on Aug. 2, 2019. She was fishing for walleyes with a small minnow for bait when instead of a walleye, this northern took the bait. Iowa's Spirit Lake fish hatchery is one facility in Iowa that will raise northerns from eggs released from spawning adult fish. Near around-the-clock activities are required by DNR fisheries staff at Spirit Lake at this time of year. The Spirit Lake hatchery is open to public visits that began on April 9. Public hours are 8 a.m. until 8 p.m. daily, until all northern netting is completed. Iowa's Spirit Lake and adjacent East and West Okoboji Lakes are glacially created depressions in the landscape that were likely made when large blocks of deteriorating retreating ice were isolated and melted in place at about 12,000 years ago.

Fish, primarily walleye and northern pike, are subject to a lot of attention at this time of year. From late March, ice out times, and into early April, adult fish are feeling the urge to spawn.

Reproduction is one of their life goals. So fisheries biologists have to work long hours to gill nets or use other special nets to capture these large adult male and female fish.

Northern Pike is one species that requires a bit of help to insure the survival of eggs from hatching, through fry stages, and into young fingerlings able to grow large enough for eventual stocking into other satisfactory Iowa lake waters. Stocking of these hatchery-raised fish helps out a lot where natural reproduction is very low or non-existent. Crew from the Iowa DNR fisheries bureau understand their jobs, and work long and hard to help Mother Nature do her job.

Northern Pike like to move into shallow slough waters with lots of emergent aquatic vegetation even before the ice from last winter has melted away. As the adult fish seek out egg laying areas, biologists have noted the vulnerability of northerns being captured in special nets.

Once caught, the live fish are taken to the hatchery located at the south end of Spirit Lake. The adult female can be massaged to release her eggs. An adult male’s milt will also be extracted, and eggs and milt will be gently mixed in special jars for incubation. Fresh water is allowed to continually flow over the eggs and bring oxygen into the mix.

DNR fisheries crews captured 254 adult northerns in 10 days. From those adult fish, over 1.3 million eggs were obtained. Two weeks time is all that is needed to ensure most of those 1.3 million eggs will hatch into small critters called fry.

Most will be transported to other selected lakes for release. Some will be retained to grow larger for other special stocking areas.

You can observe the fish hatchery operation at Spirit Lake. Take a road trip to the Great Lakes region of Iowa and see for yourself how the intense operation of assisting these fish to get a head start on life is accomplished.

Hours are 8 to 8 daily at the hatchery. From now until a few weeks from now, it is open for public viewing by visitors. To learn more about the Spirit Lake hatchery, a recorded phone message is available at 712-336-1840.

Northern pikes are a common species but are rarely abundant. Most native northern habitats that are suitable are found in larger natural lakes, major inland streams and boundary waters of the Mississippi and Missouri.

Yes, they can be found in other streams occasionally. They are voracious by nature, being a top predator that seeks out insects and insect larvae while young, and switching over to smaller fish, frogs, crayfish and even if the opportunity presents itself, young ducklings and other birds on the water.

The stomach of a northern was carefully examined, a long time ago by a former biologist, to determine the diet of that fish. The discovery showed 27 young of the year yellow perch. Other fish eaten could include shiners, and young pan fish like bluegill. Then on occasions, stomach contents may show frogs, small rodents caught swimming at the surface, a duckling or even young muskrats.

Another biological fact about northern pike females is that the number of eggs she produces goes up as she ages. Females 13-15 inches long can easily have 7,500 eggs.

Larger fish from 25 to 28 inches produced 63,000 eggs, and when even bigger at 25 to 30 pounds of live weight, the egg tally can be as much as 250,000 to 500,000!


Walleye fish are also a top priority to receive hatchery attention. Walleye netting by DNR crews are well underway at Clear Lake, Rathbun Reservoir, Storm Lake and the Iowa Great Lakes. Gillnets are set at night in lake site places known to be sought out by adult walleyes that are ready to spawn. When the nets are pulled, the fish have to be carefully removed and placed in aeration tanks on the boat.

It may be an almost all night operation at this time of year. Females with a ripe internal egg mass are carefully released of her eggs. She and her male counterparts will very quickly be returned to the main lake water body that same night.

The goal of walleye fish eggs to be collected numbers in the millions. In fact, 141 million eggs is the goal for hatching in 2024.

Walleye fry will in a few weeks be distributed to many other Iowa lakes all across the Hawkeye state. Hatcheries at each of the aforementioned sites will allow public visitation.

If you have time, or make time, it is an adventure in learning.


Northern Iowa has many large glacially carved lakes. The geologically youngest Ice blanket, many hundreds of feet thick, “surged” southward out of Canada, the Dakotas and Minnesota to enter Iowa about 15,000 years ago. It made great progress, fast for a glacier, from the intense pressure of all the Laurentide ice fields of Canada where ice thicknesses were in the thousands of feet.

This latest ice tongue made it as far south as where Des Moines is now located. Its western edge helped determine the eventual course of the Raccoon River. Its eastern edges have a local connection of hilly and hummocky terrain in Marshall County from Hendrickson Marsh vicinity, and continuing north to just west of State Center and then into Hardin County.

Out of the glacier came water, lots of it, melting slowly from on top of the glacier, internally through weak ice pocket holes and under the ice at the interface with the barren glacial till matrix of ground up precursors of soil. Water draining from and off the east edges of the glacial ice pack ran southeast to form the Cedar, Iowa, Skunk and other rivers.

In Marshall County, glacial water flows during brief warmer summertimes flowed in massive torrents that carved valleys of Timber Creek, Linn Creek, Minerva Creek, Honey Creek, all of which are now local major tributaries to the Iowa River. This thumbprint shaped ice mantle of north central Iowa defined the landform shapes of most of north central Iowa.

Left behind on the generally hummock type land surface were depressions filled with water. Many were shallow and ephemeral. However, the deepest of these sites are now Iowa lakes, natural lakes such as Clear Lake, Storm Lake, West and East Okoboji Lakes, Twin Lakes and many, many more.

Spirit Lake has a flat bottom and is generally only 20 feet deep. Contrast this with West Okoboji Lake where its deepest parts are 135 feet deep. All were glacially made.

As this last naturally warming interglacial time frame began to dominate, it made for the ice mantle’s deterioration (melting) to gain momentum, but the ice retreat was not uniform. It periodically stalled out, or even had temporary but short lived re advances.

Moraines developed that still show up today as multi-county long ridges (moraines) of extra hilly regions across some Iowa counties. The moraines have names given by geologists such as Bemis, Altamont, and Algona.

Reading landscape shapes is a special aspect of geology called geomorphology, understanding how and why land surfaces came to be. Learning all the varied processes of deposition, erosion by wind and water, are timeless ongoing forces of nature. How they made land surface shapes is intriguing.

Glaciers carved, molded, filled, sculpted, eroded and left its imprint in the shape of Iowa’s land surfaces. In many places where large natural lakes still exist, the message for fishermen and women who like to fish for walleyes and northerns, and other species, is that these special areas today have a long natural history tens of thousands of years in the making.

You can contemplate all these facts while waiting for a fish to bite. Enjoy your time outdoors. Enjoy your time spent fishing.


Prairie fires, the controlled types, are being conducted this week, when winds allow, by crews of the Marshall County Conservation Board. They started with select areas at the Arney Bend Wildlife Area.

In no particular order, other sites with native and/or reconstructed prairie grasses, will come parts of Stanley Mill Mitigation Area, Marietta Sand Prairie, Iowa River Wildlife Area, Klauenberg prairie, and Green Castle. Soon a decision will be made for the night burn at the Grimes Farm.

Weather will determine the specifics of this public observation opportunity. Stay tuned to local radio announcements concerning the Grimes Farm prairie management fires.


Wild turkey hunting seasons have begun. Statewide, the total take is over 2,000 tom turkeys. Marshall County turkey hunters as of mid week have recorded 11.

Turkey season number two has dates of April 12-16. Season three is April 17-23. Season four is from April 24 to May 12.

By the end of the fourth season, turkey hunters will have harvested about 14,000 of this biggest game bird.


Garry Brandenburg is the retired director of the Marshall County Conservation Board. He is a graduate of Iowa State University with a BS degree in Fish & Wildlife Biology.


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