Redbreast sunfish (Lepomis auritus) COSEWIC assessment and status report: chapter 2

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Executive Summary

Species information

The redbreast sunfish is a relatively small fish with a deep, laterally compressed body, which is golden brown to olive in colour, with the back being darker and the sides lighter. There are often inconspicuous reddish spots and bluish streaks along the sides, being most prominent on the head. The ventral surface, or breast, may vary from a yellowish hue to a bright orange-red from which it derives its common name. It is easily distinguished from other sunfishes by the long, narrow, opercular flap (gill cover) that is entirely black, lacking a coloured band around the border as found in some other species. The average size is 130 to 180 mm total length.

Distribution

Historically, the species (native) range was east of the Appalachian Mountains, from New Brunswick in the north, to Florida in the south. It has been introduced west to Mexico, and abroad to Italy and Puerto Rico. In Canada, the redbreast sunfish has been reported from only southwestern New Brunswick where it has been documented from eight lakes and seven rivers or streams, all within the Saint John River drainage.

Habitat

This species is found in slower sections of rivers and vegetated lake margins over a variety of substrates. It appears to prefer clear waters with abundant cover. In winter, redbreast sunfish congregate in deeper waters and remain inactive under the ice until spring.

Biology

Redbreast sunfish spawn in the spring when water temperatures approach 20°C. The male excavates the nest, which can be as large as 102 cm in diameter, in depths of up to 43 cm of water. Females are assumed to quickly enter the nest and deposit eggs; the male defends the eggs and guards the developing larvae until they disperse 1-2 weeks after hatching. The young feed mainly on tiny aquatic invertebrates, while adults eat a variety of invertebrates, aquatic vegetation, and small fish.

Population sizes and trends

There are abundance data for only one population of redbreast sunfish; that is, a population estimate of 810 ±115 at Yoho Lake in 2005. However, there are additional sites for which sampling conducted over different years suggests the persistence of populations in some lakes and rivers, but populations in at least 3 lakes and 2 rivers have not been recently confirmed.

Limiting factors and threats

The redbreast sunfish is at the northern fringe of its range in New Brunswick. While there is potential for the documentation of additional sites, the patchy distribution suggests that the species is not widespread. Its apparently limited mobility makes it less likely to expand rapidly into available habitat, even within the same watershed.

Anthropogenic influences, including urban, agricultural, industrial, and forestry practices may have an effect on aquatic systems in general.

Special significance of the species

Sunfishes are not generally regarded by anglers as a sport or food fish, and the redbreast sunfish, because of its small size, is probably one of the least important of the family. However, they are known to take live bait and, on light tackle may be attractive to young anglers in particular. They do well in captivity and are good test animals in the laboratory. The redbreast sunfish is of special significance because of its limited distribution in Canada, occurring only in waters of southern New Brunswick.

Existing protection or other status designations

The redbreast sunfish was assessed by Committee on the Status of Endangered Wildlife in Canada (COSEWIC) in 1989, and listed as a species of Special Concern. It is currently listed on Schedule 3 of the Species at Risk Act (SARA), which requires a re-assessment prior to consideration for listing under SARA. General protection is available under sections of the Fisheries Act relevant to protection of fish and their habitat. They are given no specific status in the New Brunswick angling regulations, as anglers do not generally target the species.

COSEWIC History

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list. On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.

COSEWIC Mandate

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species for the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens.

COSEWIC Membership

COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal entities (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biodiversity Information Partnership, chaired by the Canadian Museum of Nature), three non-government science members and the co-chairs of the species specialist subcommittees and the Aboriginal Traditional Knowledge subcommittee. The Committee meets to consider status reports on candidate species.

Definitions (2008)

Wildlife Species

A species, subspecies, variety, or geographically or genetically distinct population of animal, plant or other organism, other than a bacterium or virus, that is wild by nature and is either native to Canada or has extended its range into Canada without human intervention and has been present in Canada for at least 50 years.

Extinct (X)

A wildlife species that no longer exists.

Extirpated (XT)

A wildlife species no longer existing in the wild in Canada, but occurring elsewhere.

Endangered (E)

A wildlife species facing imminent extirpation or extinction.

Threatened (T)

A wildlife species likely to become endangered if limiting factors are not reversed.

Special Concern (SC)^Footnotea

A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats.

Not at Risk (NAR)^Footnoteb

A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.

Data Deficient (DD)^Footnotec

A category that applies when the available information is insufficient (a) to resolve a species' eligibility for assessment or (b) to permit an assessment of the species' risk of extinction.