The Warmouth . . . a Species at Risk

This species has been identified as Special Concern by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). It is listed under the federal Species at Risk Act (SARA) and is afforded protection under the SARA. Additional protection is afforded through the federal Fisheries Act. Under the SARA, a management plan has been developed for this species.

General Description

Lepomis gulosus

© J. R. Tomelleri

The Warmouth (Lepomis gulosus) is a member of the Sunfishes family (Centrarchidae) and has the following characteristics:

• Small sunfish (up to 30 cm long) with an oval, compressed shape;
• Large mouth with projecting lower jaw;
• Band of tiny teeth on the tongue;
• Dorsal fin comprises both soft and spiny rays;
• Approximately five dark lines radiating from the snout and eye across the cheek;
• Dark markings on the sides suggestive of vertical bands; and
• Usually yellow or brown above fading to yellow or white on the underside.

Distribution

The Warmouth is widespread in the eastern United States, ranging from the lower Great Lakes south to Florida, and west to Kansas. In Canada, the species has only been reported in Lake Erie in southwestern Ontario at Rondeau Bay, Long Point Bay and Point Pelee.

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Habitat and Life History

A warmwater species, the Warmouth prefers silt-free marshes, ponds and lakes with abundant aquatic plant cover and mucky substrates. In spring and early summer, males gather in loose colonies and build nest depressions for the females to lay eggs. The males then guard their nest and eggs fiercely. The Warmouth spawns at one to two years of age, and females lay 800 to 34,000 eggs depending on size. The lifespan is eight to nine years.

Diet

The Warmouth feeds on small fishes, crayfishes and aquatic insects, and is likely to eat proportionally more fishes than most sunfishes.

Threats

First recorded in Ontario in 1966, the Warmouth may be a relative newcomer. Alternatively, it may have always been uncommon and gone undiscovered. The draining of marshes is a potential threat to the species, but currently Ontario populations live in protected areas and are in no immediate danger. With similar ecological requirements to other sunfishes, suitable habitat should theoretically be abundant in Ontario.

Similar Species

Similar in appearance to the Rock bass (Ambloplites rupestris) and Green Sunfish (Lepomis cyanellus); however, Rock Bass have more anal spines (six versus three) and Green Sunfish do not have teeth on the tongue or dark lines radiating from the eye.

Text Sources: Trautman 1981; Crossman et al. 1994.

For more information, visit the SARA Registry Website at www.SARAregistry.gc.ca.