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Fish

Roughly 20 different game fish live in Winnebago County ponds and rivers. To improve habitat for many of these species, the District installs “fish cribs” at several lakes. Fish cribs are made from wooden pallets, cement blocks, invasive brush, PVC piping, clay tiles, Christmas trees, snow fencing or old storm-sewer pipes. They provide shelter for smaller species and ambush sites for predators. In winter, ecologists place fish cribs on frozen lakes where the water below is over 18 feet deep. When the ice thaws in the spring, the cribs sink to the bottom.

Winnebago waters also contain over 30 species of smaller “nongame” fish, some threatened or endangered. Some of these fish, such as shiners and darters, may reach only 2 or 3 inches in length, but they occupy important places in the food web. They consume small organisms, such as aquatic insects and fish eggs, and in turn are prey for larger fish and water birds. Some even serve as beneficial short-term hosts for the larvae of certain freshwater mussels. Because many of these smaller species do not tolerate pollution, their presence — or absence — gives ecologists an idea of the overall health of a water system.

Black Bullhead (Ameiurus melas)

Average Length: 7 – 9″
Average Life Span: 3 years
Features: Olive to black with white to bright yellow belly; light band at base of slightly notched tail fin
Habitat: Tolerates muddy waters, soft bottoms and pollution more than other catfish
Diet: Insects, crayfish, worms and small fish at night

Black Crappie (Pomoxis nigromaculatus)

Average Length: 12″
Average Life Span: 5 – 6 years
Features: Mottled head, back and sides with dusky or black blotches; seven or eight dorsal spines
Habitat: Clear water; less tolerant of silt and turbidity than white crappie
Diet: Zooplankton and insect larvae as fry then small fish

Bluegill (Lepomis macrochirus)

Average Length: 5″
Average Life Span: 5 – 6 years
Features: Short black gill cover; black spot at posterior end of dorsal fin; bluish lower cover of dorsal fin
Habitat: Lakes, ponds and streams
Diet: Insects and larvae

Channel Catfish (Ictalurus punctatus)

Average Length: 14 – 15″
Average Life Span: 7 – 8 years
Features: No scales; eight barbels; deeply forked tail; rounded anal fin; single hard spine in pectoral and dorsal fins
Habitat: Lakes, ponds and rivers
Diet: Seeds, fruits, insects, crayfish, snails and worms

Common Carp (Cyprinus carpio)

Average Length: 18 – 30″
Average Life Span: 7 – 8 years
Features: Two pairs of barbels near corners of mouth; mouth opens downward; one saw-toothed spine in dorsal and anal fins
Habitat: All waters
Diet: Plants and animals

Flathead Catfish (Pylodictis olivaris)

Average Length: 20″
Average Life Span: 15 – 20 years
Features: Flattened head; tiny eyes; squarish tail; protruding lower jaw
Habitat: Deep pools, lakes, and large, slow-moving rivers
Diet: Bass, bream, shad, crayfish and other catfish

Gizzard Shad (Dorosoma cepedianum)

Average Length: Up to 22″
Features: Grayish or silvery blue above; silver on sides; white below; long last ray; deeply forked caudal fin
Habitat: Clear and silty rivers and lakes; typically near the surface
Diet: Zooplankton

Grass Carp (Ctenopharyngodon idella)

Average Length: 8″ – 4′
Average Life Span: 12 – 15 years
Features: Chubby, torpedo-shaped body; slightly oblique mouth with nonfleshy, firm lips; no barbels; nonbreeding hybrid stocked to control aquatic vegetation
Habitat: All waters
Diet: Aquatic plants

Green Sunfish (Lepomis cyanellus)

Average Length: 2 – 6″
Average Life Span: 4 years
Features: Dark green-blue fading to light green on sides; yellow to white along belly; faint vertical bars on sides; some turquoise spots
Habitat: Slow pools, moderate-grade streams or rivers
Diet: Insects and fish

Largemouth Bass (Micropterus salmoides)

Average Length: 18″
Average Life Span: 5 – 6 years
Features: Upper jaw extends beyond eye when mouth closed (versus smallmouth); dorsal fins separated by deep notch; dark lateral stripe length of body
Habitat: Lakes, ponds and rivers
Diet: Fish and crayfish

Muskellunge (Esox masquinongy)

Average Length: 2 – 5′
Average Life Span: 10 – 26 years
Features: Silver, brown or green with dark vertical spots (versus northern pike); dark on light background (versus northern pike); no scales on the lower half of gill cover
Habitat: Clear waters along weed edges, rock outcrops or other structures
Diet: Mostly fish; also crayfish, frogs, ducklings, snakes, muskrats and small mammals

Northern Pike (Esox lucius)

Average Length: 20 – 60″
Average Life Span: 10 – 26 years
Features: Olive back; yellowish or whitish belly; short, horizontal spots (versus muskie); scaleless lower half gill cover (versus muskie); light markings on dark background (versus muskie)
Habitat: Sluggish streams and shallow, weedy places in lakes; cold, clear, rocky waters
Diet: Mainly fish but also water voles and ducklings; other northern pike

Quillback (Carpiodes cyprinus)

Average Length: Up to 43″
Features: Silvery; large scales; long filament from dorsal fin
Habitat: Rivers, creeks, clear lakes
Diet: Insect larvae

Redear Sunfish (Lepomis microlophus)

Average Length: 8 – 9″
Average Life Span: 3 years
Features: Dark along back; yellow-green along belly; red edge on male’s gill cover, orange on female’s
Habitat: Deep-water, mollusk-feeding niches
Diet: Snails and other shelled creatures along lake beds

Rock Bass (Ambloplites rupestris)

Average Length:6 – 10″
Features: Similar to smallmouth bass but usually a bit smaller
Habitat: Prefers clear, rocky and vegetated stream pools and lake margins
Diet: Smaller fish, insects and crustaceans

Smallmouth Bass (Micropterus dolomieui)

Average Length: 10 – 20″
Average Life Span: 8 – 10 years
Features: Upper jaw extends mid eye when mouth closed (versus largemouth); dorsal fins nearly continuous; lines radiate from nose and eye; vertical stripes on sides
Habitat: Lakes, streams and rivers
Diet: Insects, crayfish and fish

Walleye (Sander vitreus)

Average Length: 14 – 15″
Average Life Span: 10 – 12 years
Features: Large glassy eye; olive-brown body with greenish yellow reflections; dark spot at back of first dorsal fin; lower tail fin often with white tip
Habitat: Rivers, streams and lakes
Diet: Fish and insects

White Crappie (Pomoxis annularis)

Average Length: 9 – 12″
Average Life Span: 5 – 6 years
Features: 5 – 10 vertical bars (versus spots on black crappie); dorsal fin starts further back than on black crappie
Habitat: Clear water with aquatic vegetation; rivers
Diet: Zooplankton and insect larvae as fry then small fish

White Sucker (Catostomus commersoni)

Average Length:12 – 20″
Features: Long, round-bodied fish with copper, dark green, grey, brown or black back and sides and light underbelly
Habitat: Highly adaptable; tolerant of turbid and polluted waters
Diet: Aquatic insect larvae, mollusks, crustaceans, worms

Yellow Bullhead (Ameiurus natalis)

Average Length: 4 – 11″
Average Life Span: 7 years
Features: Dark olive-brown back; yellowish belly; nonmottled sides; dusky to olive fins
Habitat: Warm pools and backwaters in ponds, lakes, reservoirs and rivers
Diet: Microcrustaceans, insect larvae and fish

Yellow Perch (Perca flavescens)

Average Length: 7 – 9″
Average Life Span: 7 – 8 years
Features: Yellow body with six to nine dark bars or rings running top to bottom; hump just behind head
Habitat: Rivers and glacial lakes
Diet: Fish and insects