August 1, 2022
Photo courtesy of Vic Santucci.

Hail to The King

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By Frank Sladek

In the heart of Sand Ridge, Illinois’ largest state forest, stands a fish fortress. At 160-acres, Jake Wolf Memorial is Illinois’ largest fish hatchery. Surrounded by 7,500 acres of woods in Mason County, protected by barbed wire fences and flanked by dozens of ponds, a visitor could mistake the massive compound for a castle. Quite an appropriate comparison for a hatchery that houses royalty. Jake Wolf is not home to princes, dukes, earls or barons. It is, however, home to a king. Oncorhynchus tshawytscha, the king salmon.

A technician holds a small dark brown and silver fish in the palm of his/her hand. Overlapping the image on the right is a map of Illinois with a star indicating Mason County. The graphic has a dusky blue border.
A technician holds a six-week-old Chinook. Jake Wolf Memorial fish hatchery is in Mason County, Illinois. Photo by Frank Sladek.

Jake Wolf has been producing and stocking king salmon, also known as Chinook, for nearly 40 years. Since the hatchery began fish production in 1983, more than 25 million of these silver sportfish have been stocked in Illinois. Each May, approximately 180,000 kings are released, accounting for 6 percent of the 3 million fish the hatchery stocks each year. But out of the 16 species of fish Jake Wolf raises, only the king salmon reeks of royalty. From their pampered upbringing to the massive kingdom they eventually oversee, Jake Wolf’s salmon live up to their royal moniker.

The life of an Illinois king salmon begins in mid-October, when Jake Wolf staff travel north to collect eggs. Each fall, four-year-old salmon make their way into Great Lakes tributaries to spawn and ultimately die. Hatchery staff travel to these tributaries, such as the Little Manistee Weir in Michigan or the Root River in Wisconsin, to assist state fisheries staff with collecting and fertilizing eggs. Fertilized eggs are then divvied up amongst participating states, with a portion brought back to Jake Wolf for incubation.

Technicians sit in a row lined up in front of a set of shelves with shallow tubs. Each technician has a tub and is sorting through pink fish eggs suspended in water. The background is a gray, green, and stainless steel laboratory.
Photo by Frank Sladek.

In their early stages of life, the kings are constantly coddled. For a two-month period, starting when the eggs arrive, hatchery technicians act as handmaidens to more than 700,000 unborn kings. Technicians regularly apply chemical treatments to the eggs to prevent fungus and disease while also performing a tedious task known as “egg picking.” Each day, armed with nothing more than a pair of tweezers, keen eyes, and steady hands, technicians sort through hundreds of thousands of eggs. They remove dead and diseased eggs to keep fungus from spreading while also increasing survival rates in each incubation tray. The kings demand cleanliness.

Once hatched, the newborn salmon will feed off yolk sacs attached to their bellies while they develop. Once the yolk is used up, the fish can start on solid food. Like many monarchs, the kings at Jake Wolf are quite glutinous. Our salmon do not feast on spit-roasted swine or carafes of fine wine, but every 15 minutes—96 feedings per day—are fed a diet of fish meal pellets. In their first six months of life, one juvenile king salmon can consume upwards of 25 pounds of pellets!

Two small silver and dark gray mottled fish are held in a technician's hand. The fish on the left has an adipose fin intact, and the fish on the left has its adipose fin clipped. In the background is a nylon netting submerged in water.
On the left, the adipose fin is intact, and on the right, the fin has been clipped. Photos by Frank Sladek.

With their daily feasting, the kings grow from ½ to 6 inches in five months. At this size they are almost ready for release. Before that happens, though, they must be marked. Royal families are often marked by their crests; flags or banners adorned with symbols including lions, swords and crosses. King salmon don’t have crests, but they are marked by another method. Before release, each salmon has its adipose fin (a small fin between the dorsal and tail fin) clipped off. The process does not harm the fish, but the fin does not grow back once removed. A common practice with salmon, fin clipping allows hatchery fish to be identified as captive born if caught. This allows biologists to track natural reproduction rates, as large numbers of clipped fish mean less natural reproduction, while less clipped fish means more natural reproduction is occurring.

A large truck with the logo of the Illinois Department of Natural Resources on the side parks on a pier above lake water. The truck has a tube that allows water and fish to flow from the pool in the bed of the truck to the lake water. Three men are supervising the process. In the background is a partly cloudy sky.
Stocking salmon using a stocking tube, such as the one pictured in use at Waukegan Harbor, helps fisheries biologists reduce the number of fish lost to gulls. Photo by Vic Santucci.

Once released, the kings have full reign of their domain, also known as Lake Michigan to us commoners. In their massive kingdom, kings swim upwards of 20 miles a day in search of schools of baitfish, often in depths of 50 to 200 feet of water. And speaking of water, kings prefer their water quite cold. With an optimum operating temperature of 55o Fahrenheit, the salmon travel far and wide to stay at this temperature year-round, often utilizing a lake’s “thermocline” for temperature regulation. Many kings have been known to travel the tristate area (Illinois, Wisconsin and Indiana) to find food and ideal temperatures.

Oddly enough, the empire that the kings oversee is not their native land. Originally stocked in the mid-1960s, king salmon were introduced into the Great Lakes from the West Coast with another transplant, the Coho salmon, to control an invasive species of baitfish called alewife. These oily baitfish were once an enemy of the Great Lakes, drastically altering the lakes’ food web and washing up dead, by the millions, on public beaches. Like a knight in shining armor, the kings arrived and brought balance and prosperity to an ecosystem in shambles. With their insatiable appetites and strong swimming skills, the kings were the perfect alewife hunters, quickly knocking their numbers down to manageable levels.

The king’s introduction into the lake also birthed a multi-billion-dollar sport fishery. In just four years, a 6 inch fingerling salmon can reach 40 inches in length and weigh more than 40 pounds. Their large size and tackle testing power have earned kings a large following of loyal subjects, attracting millions of anglers from around the country. This includes fleets of charter boats, specifically designed to track down far-roaming pods of salmon in the lake’s vast expanses. But one does not need a boat to catch a king.

A graphic with a photo of a pipe with water and fish flowing through it to the teal water below. Under the photo is a solid gray background with white text.
Find out more about the IDNR Hatchery system in Illinois here. Learn how to participate in the Lake Michigan’s world class fishery here. Photo by Frank Sladek.

Come late August in Illinois, the Chicago shoreline becomes lined with seekers of chinook. As water temperatures cool, four-year-old fish return to spawn in many of the harbors they were stocked. Most people will never lay eyes on the king’s subjects though, as the best times to target fall run salmon is from dusk till dawn. If you happen to see the king’s followers, you’ll be treated to quite the spectacle. Anglers lined up in darkness with large hunks of glowing metal hanging on the end of their lines. Known as “spoons,” these heavy lures are covered in glow paint to attract (and irritate) spawning salmon. To onlookers, a group of anglers slinging glow spoons resembles medieval archers firing flaming arrows into the night sky. The kings’ homecoming is always a flashy affair.

Talk with those who have battled kings and you will be regaled with wide-eyed tales of screaming reels, broken lures and epic fights. Out of all the sport fish in our state, king salmon are one of the few that can make an angler bow down to them. Is this due to their muscular bodies and incredible stamina or the respect their subjects have for them? Jake Wolf Memorial Fish Hatchery continues to stock salmon each year so anglers have a chance to rumble with royalty and find out for themselves what makes this fish the crown jewel of the Great Lakes. Hail to the king.


Frank Sladek is a naturalist/environmental educator from the West Side of Chicago. He has done presentations on YouTube, NBC and PBS. As the Natural Resources Coordinator at Jake Wolf Memorial Fish Hatchery, Sladek conducts public tours, visits schools, breeds zooplankton and raises endangered dragonflies.

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