Many Great Lakes fish species use wetlands for feeding, cover, spawning, and nursery habitat. Some fish stay in marshes for most of the year, but seasonal visits are more common.

Those fish that spawn in the early spring after the ice melts leave immediately after depositing their eggs. These fish, which include Northern Pike, take advantage of the warm shallow water temperatures and high dissolved oxygen levels in the water, which is required for egg respiration.

Other fish spawn in late spring to early summer, and the male stays with the eggs, fanning them to provide the needed oxygen, and guard the eggs from predators. An example of these fish includes the Largemouth Bass.

Second Marsh once sustained large populations of game fish such as Northern Pike and Smallmouth Bass. Due in part to water level changes and an increase in sediment loading, these species have been much reduced in numbers. The Common Carp is present in Second Marsh. This species has greatly increased in numbers and is becoming destructive, by disturbing sediments and destroying the vegetation. The marsh restoration project is designed to create a more balanced fish population and manage nuisance plant species.

The official list of species in Ontario according to the Ontario Ministry of Natural Resources (Oct. 1997) stands at 158 species.  Of these, 57 species have been recorded for the Second Marsh, Harmony, Farewell and Black Creeks and the immediate offshore waters.

Picture of Oshawa Second Marsh

American Brook Lamprey

Sea Lamprey


American Eel


Gizzard Shad


Common Carp

Brassy Minnow

Common Shiner

Golden Shiner

Emerald Shiner

Blacknose Shiner

Spottail Shiner

Rosyface Shiner

Sand Shiner

Pearl Dace

Northern Redbelly Dace

Finescale Dace

Bluntnose Minnow

Fathead Minnow

Blacknose Dace

Longnose Dace

Creek Chub

Longnose Sucker

White Sucker

Brown Bullhead

Channel Catfish


Tadpole Madtom

Northern Pike

Central Mudminnow

Rainbow Smelt

Coho Salmon

Rainbow Trout

Chinook Salmon

Brown Trout


Brook Trout

Banded Killifish

Brook Stickleback

Mottled Sculpin

Slimy Sculpin

White Perch

White Bass

Rock Bass



Smallmouth Bass

Largemouth Bass

Black Crappie

Rainbow Darter

Iowa Darter

Least Darter

Johnny Darter

Yellow Perch