Muskie: Size by Age, Weight by Length, and How to Tell It From a Pike

The muskie, or muskellunge (Esox masquinongy), is the largest member of the pike family: most fish an angler meets are 30 to 42 in (76–107 cm), and 50 in (127 cm) is the line where a muskie becomes a trophy. It is Wisconsin’s state fish, a lone ambush hunter of weed edges and drop-offs, and the hardest freshwater fish in North America to put in a net. Below: how big muskie get and how old a fish of each length is, what a 50-incher weighs, how to tell a muskie from a northern pike in ten seconds, and what the surveys say it takes to catch one.

Wisconsin’s creel clerks counted it: one muskie for every 27 hours of fishing. And when biologists opened the stomachs of 1,092 Wisconsin muskies, they found six walleye.

How big do muskie get?

The National Park Service gives the average as 30 to 42 in (76–107 cm). Muskellunge kept by Wisconsin anglers between 1990 and 2011 averaged 38.5 in (98 cm). On a good lake a female can pass 50 in (127 cm) and 40 lb (18 kg), and the heaviest muskie certified in the United States this century weighed 58 lb (26.3 kg).

How fast a muskie gets there depends on the water. The Wisconsin figures below are the statewide average of 5,043 aged fish; Michigan’s come from its own statewide table.

So a 40 in muskie is about eight or nine years old, and a 50-incher is a fish in its late teens. Jerry Younk, a Minnesota DNR research biologist, puts it this way: depending on the lake, a Minnesota muskie needs 13 to 21 years to reach 50 in. The oldest fish he aged was 22; Wisconsin has documented muskies of 30.

Many never get there at all. Lake size explains about two thirds of the difference between lakes in northeastern Wisconsin: waters of 2,000 acres (800 ha) and more are the ones that grow 50 in fish, while lakes down to 100 acres can still grow a 40 in fish.

And nearly every giant is a female. In a Minnesota sample of fish that anglers kept, 26% of the females were longer than 47 in (119 cm) against 1% of the males. Females there grow toward an average final length of 54.2 in (138 cm), males toward 46.1 in (117 cm).

How much does a 50 inch muskie weigh?

Between 30 and 40 lb (14–18 kg) for an average fish, and 39.5 lb (18 kg) for a well-fed one. The two answers come from two different curves.

Wisconsin DNR publishes the average: 10 lb at about 33 in, 20 lb at about 41 in, 30 lb at about 47 in and 40 lb at about 52 in. The chart copied across the internet is the standard-weight equation of Neumann and Willis, built from 4,343 fish in 16 states. Rob Neumann himself notes that it describes the 75th percentile, a fish in above-average condition.

Trust the chart less as the fish gets longer. It says 64.8 lb for a 58 in muskie. Joe Seeberger’s 58 in Michigan fish, weighed on a certified scale in 2012, went 58 lb (26.3 kg). Nolan Sprengeler’s Minnesota record of 2021 measured 57¾ in and weighed 55 lb 14.8 oz (25.4 kg). For any muskie over about 50 in, measure the girth as well; length alone flatters it. The fish weight calculator works it out from both.

Muskie or northern pike: the ten-second check

Three marks settle it, and every state agency lists them in the same order.

1. Count the pores under the jaw. Iowa DNR: five or fewer on each side is a pike, six or more on either side is a muskie. This one works on faded and unmarked fish too.
2. Look at the pattern. A muskie has dark bars or spots on a light body, or no marks at all. A northern pike is the reverse: rows of pale, bean-shaped spots on a dark green body.
3. Look at the tail. Muskie tail tips are pointed. Pike tail tips are rounded.

Two more for a fish in the hand: a muskie’s cheek carries scales on its upper half only, where a pike’s cheek is scaled all over, and muskie fins are pointed and usually rust-colored. Muskies come in three patterns: clear, barred and spotted. In Michigan the spotted fish are mostly Great Lakes muskies and the barred ones live in the southern inland lakes.

The tiger muskie is the cross of the two. It has the pike’s rounded tail tips and bold dark bars on a light body.

Where muskie live

The native range runs through the Great Lakes and St. Lawrence basin and the upper Mississippi, from Quebec to southeastern Manitoba, and south through the Ohio River country. Wisconsin alone has 667 muskie lakes and 100 river stretches, almost nine in ten of them in the north of the state. Minnesota manages 101 waters, Michigan 116. Stocking has carried the fish well beyond that, and in Maine’s St. John River it is an unwanted invader with no size or bag limit.

A muskie is a solitary fish with a small home range. Wisconsin DNR places it near drop-offs, rock and sand bars, weed edges and weedy bays, and in the deep, slow pools of medium and large rivers. It is comfortable in water up to about 78 °F (26 °C); big fish avoid water warmer than 77 °F (25 °C) and slide deeper in a hot summer. The temperature chart for 25 species shows where that sits next to pike and walleye.

There are never many. A good Wisconsin lake holds about one adult for every two or three acres. Michigan DNR reckons a 1,000-acre lake probably holds fewer than 500.

What muskie eat, and the walleye question

Fish, almost entirely, and not the ones anglers accuse them of. In 34 northern Wisconsin lakes, biologists examined 1,092 muskies. Yellow perch made up 30% of the diet and white suckers 8%. Six walleye turned up.

Minnesota repeated the work on 12 lakes between 2019 and 2022. Of 350 stomachs with food that could be identified, four held a walleye. Yellow perch again came first, then suckers. A separate Minnesota study found that muskies ate 6 to 16% of the food taken by the top predators in three lakes, while northern pike ate 38 to 50%.

A muskie can swallow a fish two thirds of its own length; Wisconsin DNR’s example is a 50 in muskie handling a 33 in meal. Muskrats, ducklings and frogs are on the record too, rarely. The fish hunts by sight, which is why clear water and daylight suit it.

When muskie spawn

When the shallows warm from 50 to 60 °F (10–16 °C), which is mid-April to late May in Wisconsin and a week or two after the northern pike have finished. There is no nest. A pair swims side by side over several hundred yards of shoreline in the warm shallows, scattering 20,000 to 200,000 eggs, and then leaves them. The fish return to the same bays each year.

How to catch a muskie: what the surveys say

“The fish of 10,000 casts” has a measured version. Across Wisconsin’s better muskie waters, creel surveys from 1990 to 2011 recorded one muskie per 27 hours of fishing. On 18 Minnesota waters the figure runs from 11 hours to 200, with an average of 40. On Green Bay in 2021 it was just under 20.

What the agencies say improves those odds:

• Season. Catch rates are best in the warm months, and the biggest fish come late. Minnesota DNR: many of the largest muskellunge are caught in October and November.
• Weather and light. Wisconsin DNR lists windy, rainy or muggy overcast days and the hours before a front. Minnesota adds dawn and dusk.
• Water. Small, shallow, weedy lakes give more action and smaller fish. Big, deep, clear lakes give long waits and the chance of a giant.
• Tackle for casting. A 7 to 9 ft (2.1–2.7 m) heavy casting rod, 50 to 80 lb braid and a foot-long steel or fluorocarbon leader. Lures run 5 to 10 in and more: bucktails, spinnerbaits, jerkbaits, big crankbaits.
• The figure eight. Muskies follow a lure to the boat without striking. Both agencies describe the answer: keep the lure moving and sweep it in a wide figure eight beside the boat at the end of every cast.

Releasing a muskie alive

Almost every muskie caught today goes back: members of Muskies Inc. release more than 99.9% of the fish they report. In cool water that works. An Ottawa River study radio-tagged 30 released muskies and lost none, and Wisconsin DNR puts delayed mortality under 5%.

Warm water is the exception. Maryland DNR tagged Potomac River muskies released above 80 °F (27 °C), and 10 of 21 died. The agency asks anglers to stop targeting muskie at that temperature.

Unhook the fish in the water, in a large net, with long-nosed pliers; cut hooks that will not come free. Lift it level with a hand under the belly for the photo, never by the jaw alone.

Records and size limits

Three fish are called the record, and each has a body behind it. The IGFA lists Cal Johnson’s 67 lb 8 oz (30.6 kg) muskie from Lac Courte Oreilles, Wisconsin, caught July 24, 1949. The National Fresh Water Fishing Hall of Fame and Wisconsin DNR list Louis Spray’s 69 lb 11 oz (31.6 kg) fish, caught three months later near the same town, Hayward. Art Lawton’s 69 lb 15 oz St. Lawrence muskie of 1957 held the title for 35 years until both bodies threw it out in 1992, after an investigator matched it to a photo of a fish captioned at 49 lb 8 oz.

Size limits show how each state values a big fish: 40 in (102 cm) on most Wisconsin waters, 42 in (107 cm) in Michigan, and 54 in (137 cm) statewide in Minnesota. Check the current regulations for the water you fish; several lakes carry their own limit.

Related

• Pike, muskie and pickerel: the whole family told apart, with the record for each.
• Fish species: every species guide in one place.
• Water temperature for fishing: feeding, spawning and stress temperatures for 25 species.
• Yellow perch: the fish a muskie eats most.