Redear sunfish are native to the central and southern United States and can be found in the St. Lawrence-Great Lakes and Mississippi River drainages, as well as the Atlantic and Gulf Slope drainages. Redear sunfish have been introduced as game fish throughout the United States, as well as in Morocco, South Africa, Panama, and Puerto Rico.

Biogeographic Regions: nearctic (Introduced , Native ); palearctic (Introduced ); ethiopian (Introduced ); neotropical (Introduced )

occurs (regularly, as a native taxon) in multiple nations

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Native to Atlantic and Gulf Slope drainages from about Savannah River, South Carolina, to Nueces River, Texas; north in Mississippi River basin to southern Indiana and Illinois (Page and Burr 1991). Introduced in many areas west and north of native range. Common.

Redear sunfish have laterally compressed bodies that are green, grey, or black. They can be distinguished from other sunfish via 3 different characteristics: 1) the red or orange margin on the opercular flap, 2) cheeks without conspicuous orange and blue streaks, and 3) pectoral fins that are greater than a third of the length typically found in sunfish. They often have small green specks on their heads and grey or black specks covering their bodies. Their pectoral fins have 13 to 14 pectoral rays, which taper to a terminal point. Their dorsal fin has 10 to 11 spines, and the anal fin has 3 spines. The terminal end of the opercular flap is marked by a large black spot, accompanied by two smaller white spots. The brightly colored terminal margin on the opercular flap is red in males and orange in females. At sexual maturity they are approximately 224 mm and can weigh as much as 454 g.

Redear sunfish are similar in appearance to their close relative, pumpkinseed sunfish (Lepomis gibbosus). As a result, the two species are often confused for one another. However, pumpkinseed sunfish have a number of wavy iridescent lines along the check and opercular flap that are not present in redear sunfish.

Range mass: 1.3 (high) kg.

Range length: 35.5 (high) cm.

Average length: 22.4 cm.

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry

Sexual Dimorphism: sexes colored or patterned differently

Length: 25 cm

Redear sunfish prefer warm and calm or stagnant waters. As a result, preferred habitat is restricted to ponds, lakes, river backwaters, and reservoirs. The riverine habitats in which they are found, tend to be large and slow flowing with moderate amounts of aquatic vegetation. Redear sunfish are mainly found in water that is at least 2 m deep. They commonly live in low salinity waters (less than 4 ppt) but have been found in waters with salinities as high as 12 ppt.

Average depth: 2 m.

Habitat Regions: temperate ; tropical ; freshwater

Aquatic Biomes: lakes and ponds; rivers and streams

Wetlands: marsh

Habitat Type: Freshwater

Comments: Deeper waters of warm quiet ponds, lakes, backwaters of small to medium rivers, reservoirs, and swamps; usually in clear water with abundant vegetation, stumps, logs, or other cover, with substrate of mud or sand. Occasionally occurs in brackish water. Eggs are laid in a nest made by the male in shallow water on bottom; often nests in colonies.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Redear sunfish are mainly bottom feeders. Fry stay in benthic waters and feed on algae and microcrustaceans. Juveniles eat insects, insect larvae, and small snails. Once their jaws fully develop, usually at about 1 year old, they begin to feed exclusively on snails. Adults feed on snails, aquatic insects, copepods, and organisms with hard shells, such as crustaceans. Evidence suggests that redear sunfish prefer snails with moderate shell thickness, as opposed to thin or thick shelled snails.

Animal Foods: insects; mollusks; aquatic or marine worms; aquatic crustaceans; zooplankton

Plant Foods: algae

Primary Diet: carnivore (Molluscivore )

Comments: Eats snails, aquatic insect larvae, and small crustaceans obtained from bottom or from plant surfaces (Moyle 1976). Pharyngeal jaws are specialized for crushing hard-shelled prey.

Introduced redear sunfish have significantly impacted native fish populations. For example, when introduced into habitats occupied by pumpkinseed sunfish (Lepomis gibbosus), pumpkinseed populations significantly declined. Redear sunfish have strong jaws, which allow them to crack mollusk shells more easily than pumpkinseed sunfish can. As a result, redear sunfish likely decrease food availability for pumpkinseeds.

Redear sunfish are host to the non-native parasitic copepod, Neoergasilus japonicus. Neoergasilus japonicus attaches to the outer surface of its host, likely feeding on the dermal tissue underlying the scales. Gut content analysis, however, shows that the primary diet of free-swimming N. japonicus consists primarily of blue-green algae.

Commensal/Parasitic Species:

• Parasitic copepod (Neoergasilus japonicus)

Redear sunfish have several predators, including humans (Homo sapiens). They are considered a sport-fish species and are stocked in many lakes and streams. Humans commonly consume them and their larvae are prey to many other sport-fish species, including largemouth bass (Micropterus salmoides) and catfish (Genus: Ictalurus). Redear sunfish avoid predation by retreating to shaded areas and deeper waters. Redear sunfish carcasses are often scavenged by birds and raccoons (Procyon lotor).

Known Predators:

• largemouth bass (Micropterus salmoides)
• catfish (Ictalurus)
• humans (Homo sapiens)

Anti-predator Adaptations: cryptic

Redear sunfish use several modes of communication. It has been suggested that Lepomis species use chemical cues during nest building. During spawning, redear sunfish swim in a circular pattern around their mates. Males produce a popping sound to induce egg laying in females, which they produce by clapping the jaws shut. Finally, females select mates, at least in part, based on the pattern and intensity of a potential mate's coloration.

Communication Channels: visual ; acoustic ; chemical

Perception Channels: visual ; acoustic

Optimal incubation temperatures for redear sunfish eggs range from 22°C to 24°C. Incubation normally lasts 50 hours. After hatching, fry hide in gravel nests until about 3 days after hatching. Juveniles stay close to aquatic plants for protection and at 1 year old, leave the protective cover of aquatic plants to prey on open-water snails.

Growth rates appear to be dependent on turbidity as redear sunfish grow more rapidly in less turbid water. Different age classes can be identified according to size. First year fish range from 50 to 100 mm in total length (TL), and second year fish range from 110 to 140 mm TL. Fish that are 5 to 6 years old range from 200 to 250 mm TL.

Development - Life Cycle: indeterminate growth

Redear sunfish have an average lifespan of 6 years. The oldest wild-caught redear sunfish was 8 years old at time of capture. In captivity they can live to be 7 years old.

Range lifespan

Status: wild: 8 (high) years.

Range lifespan

Status: captivity: 7 (high) years.

Average lifespan

Status: wild: 6 years.

During mating season, male redear sunfish make popping sounds while in close proximity to females, which are used to gain the attention of potential mates. During courtship, males repeatedly surge toward potential mates while making popping sounds, which are made by clapping the jaws shut. Males also gain the attention of females via chemical and visual cues.

Male redear sunfish construct nests made from sand, gravel, and mud. Nests are typically found near aquatic plants, which provide cover for juveniles prior to maturation. Nests are approximately 25 to 61 cm wide and occur anywhere from 1 to 6 m deep. After fertilization, males do not leave the nest until all their eggs have hatched. Female sunfish lay their eggs in several nests each mating period.

Mating System: polyandrous

Redear sunfish mate once per year. The start of spawning season depends on water temperature, with warmer temperatures resulting in earlier spawning. Spawning typically occurs in shallow water at temperatures between 21°C and 24°C. Spawning begins in early spring and ends in mid-summer but may extend into early October in warmer climates. Maturation rates are also dependent on climate, as individuals start to spawn at 1 year old in warmer climates and at 2 years old in colder climates. Finally, female sunfish produce between 9,000 and 80,000 eggs per mating season.

Breeding interval: Redear sunfish breed once yearly.

Breeding season: Redear sunfish breed from early spring to mid-summer.

Range number of offspring: 9000 to 80000.

Average time to hatching: 50 hours.

Average time to independence: 3 days.

Range age at sexual or reproductive maturity (female): 1 to 2 years.

Range age at sexual or reproductive maturity (male): 1 to 2 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; sexual ; fertilization (External ); oviparous

Male redear sunfish build nests prior to spawning and protect their nest for up to 3 days after spawning.

Parental Investment: male parental care ; pre-fertilization (Protecting: Male); pre-hatching/birth (Protecting: Male); pre-weaning/fledging (Protecting: Male); pre-independence (Protecting: Male)

Spawns throughout warmer months; males guard eggs and hatchlings; spawners are generally 2 years old or older; often nests in colonies (Moyle 1976, Manooch 1984).

Redear sunfish exhibit stable population trends throughout its range and are in no danger of decline.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

There are no known adverse effects of redear sunfish on humans. However, when redear sunfish populations are introduced to non-native waters, they may negatively affect the ecosystem and out-compete native fish species. This may affect the fishing industry and overall health of ecosystems that humans depend on for food and water.

Redear sunfish are considered a sport fish and are regularly consumed throughout United States.

Positive Impacts: food

Comments: The ranges and morphological characteristics of the two formerly distinct (but unnamed) subspecies have been obscured by extensive translocations.