Invasion History

First Non-native North American Tidal Record: 1956
First Non-native West Coast Tidal Record: 1956
First Non-native East/Gulf Coast Tidal Record: 1973

General Invasion History:

Redear Sunfish (Lepomis microlophus) is native to the Mississippi and Gulf Slope drainages from Iowa and Indiana to the Nueces River, Texas (Page and Burr 1991). Its native Atlantic Slope range is less clear, and may have ended near the Florida-Georgia border, or as far north as the Cape Fear River (Smith 1907; Fuller et al. 1999). Redear Sunfish have been widely stocked in ponds and impoundments, largely by individuals and state agencies. Redear Sunfish have been introduced to river systems in 28 states, including the Great Lakes Basin, and the San Francisco Bay Delta, the Pamlico Sound and Chesapeake estuaries (Cohen and Carlton 1995; Mills et al. 1993; USGS Nonindigenous Aquatic Species Program 2018). In its native range, L. microlophus commonly occurs in brackish estuaries (Peterson 1988; Peterson and Meador 1994). In invaded areas in the San Francisco Delta and Chesapeake Bay, it is known primarily from tidal freshwater areas (Lippson et al. 1979; Cohen and Carlton 1995: Feyrer et al. 2003; Kraus et al. 2012), but could extend its habitat range in the future.

North American Invasion History:

Invasion History on the West Coast:

Redear Sunfish were first found in California in the Colorado River in 1951, resulting from stocking in the Colorado River. The fish was deliberately stocked in southern California reservoirs in 1954, as a potential forage fish for Largemouth Bass (Micropterus salmoides, believed to be less prone to stunting than Bluegills (L. macrochirus). In 1955, Redear Sunfish were transferred to the Central Valley Hatchery, and soon planted in many private ponds in the valley. They were present in reservoirs and ponds in the San Francisco Bay watershed in the 1960s and 1970s, and collected in several tributaries in the 1980s (Coyote Creek, the Guadalupe River, and Sanchez Creek) (Wang 1986; Leidy 2007). In the 1980s and 1990s, Redear Sunfish were the second to fourth most abundant fish species in the freshwater Delta, behind Bluegill, Threadfin Shad, White Catfish, Mississippi Silverside (Feyrer and Healey 2003; Brown and Michniuk 2007; Grimaldo et al. 2012), and generally increasing over time. Two specimens were caught in the brackish Suisun marshes (Matern et al. 2001).

Invasion History on the East Coast:

Redear Sunfish were apparently not among the 'bream' or 'sun-fish' introduced by the U.S. Fish Commission, but were introduced later by state agencies, fishermen, or pond-owners, as indicated by dates of first record (late 1950s, South Carolina (Poole 1978); 1958, Virginia; Jenkins and Burkhead 1993; 1964, North Carolina, USGS Nonindigenous Aquatic Species Program 2018). Jenkins and Burkhead (1993) indicated that the distribution of this species was undersampled, because of its widespread introduction in farm-ponds. Redear Sunfish are known from North Carolina estuarine tributaries in the Cape Fear River, Bogue Sound, the Neuse and Pamlico Rivers, and Currituck Sound. The range of this fish has expanded greatly since the 1970s, when it was mostly limited to farm ponds (Menhennick et al. 1974; Menhennick 1991; USGS Nonindigenous Aquatic Species Program 2018).

In the Chesapeake Bay watershed, it was first reported from the Potomac drainage in 1958, probably collected in a stream after escaping from a stocked pond (Jenkins and Burkhead 1993). In 1956–1974, it was collected off Indian Head and Blossom Point in the fresh-oligohaline region of the tidal Potomac River (O'Dell et al. 1976). First records in other tributary basins were 1967 in the James, 1971 in the York, and 1977 in the Rappahannock (Jenkins and Burkhead 1993). The Virginia Institute of Marine Sciences Striped Bass Survey captured specimens in the tidal James, Rappahannock, and York Rivers. Abundances were low (39 fish) compared to native Pumpkinseed L. gibbosus (1731), Redbreast Sunfish L. auritus (739), and introduced Bluegill L. macrochirus (700) (Virginia Institute of Marine Sciences 1998). From 1971 to 1973 Redear Sunfish have been stocked in the Pennsylvania drainage of the Susquehanna River (Denoncourt et al. 1975b), but were not recorded below Conowingo Dam (McKeown 1984).

In 1994, a population of Redear Sunfish was found in Wagamons Pond (Sussex County DE). In 1996, this species was collected in Trap Pond (Sussex County) and the St. Jones River (Kent County) (Raasch 1996).

Redear Sunfish were first introduced to the Great Lakes basin in 1928 in lakes and ponds in Indiana. It has been introduced into many lakes in the basin, but is not established in the Great Lakes proper (Emery 1985; Mills et al. 1993).

Invasion History on the Gulf Coast:

Invasion History in Hawaii:

Invasion History Elsewhere in the World:

Redear sunfish were first introduced to Puerto Rico in 1948 and became widely introduced in reservoir on the island (USGS Nonindigenous Aquatic Species Program 2018). They were introduced as a forage fish for Largemouth Bass and as biocontrol of the snail Biomphalaria glabrata, which hosts the blood fluke Schistosoma mansoni (Lever 1996). It is also established outside its native range in Mexico and in one lake in Morocco. It may also be established in South Africa, Panama, and Mauritius, but sources are conflicting (Lever 1996; Froese and Paul 2018).


Description

The Redear Sunfish (Lepomis microlophus) is a medium-sized freshwater fish. Fishes of the genus Centrarchidae (Sunfishes and Black Basses) have a strongly laterally compressed body. They have a spiny and a soft dorsal fin, which are fused. They have 3–8 anal spines, thoracic pelvic fins, and ctenoid scales. The sunfishes of the genus Lepomis have a shallowly forked tail, a smooth edge to the gill cover, and a fleshy 'ear-flap' projecting from the gill-cover. The gill-cover has a thin, flexible rear edge. Redear Sunfish have a deep, strongly compressed, oval body, a pointed snout, a small terminal mouth (not extending to the pupil of the eye), and long, pointed pectoral fins, which extend far past the eye when bent forward. The dorsal fin has 10–11 spines and 10–12 rays, while the anal fin has 3 spines and 9–11 rays. There are 34–47 lateral line scales. The maximum length is 269 mm, but a more usual length is 135–216 mm. The back is olive, with a golden sheen. The belly is white to yellow. Juveniles have dusky gray bars, while adults are marked with dusky spots. The ear-flap is black, with a bright orange-red spots, and a white margin. Breeding males are brassy-gold with dusky pelvic fins (Hardy 1978; Page and Burr 1991; Jenkins and Burkhead 1993; Moyle 2002).

In the southeastern US, a frequent common name is 'Shellcracker', because of this fish's habit of feeding on mollusks (Moyle 2002).


Taxonomy

Taxonomic Tree

Kingdom:   Animalia
Phylum:   Chordata
Subphylum:   Vertebrata
Superclass:   Osteichthyes
Class:   Actinopterygii
Subclass:   Neopterygii
Infraclass:   Teleostei
Superorder:   Acanthopterygii
Order:   Perciformes
Suborder:   Percoidei
Family:   Centrarchidae
Genus:   Lepomis
Species:   microlophus

Synonyms

Pomotis microlophus (Günther, 1859)
Eupomotis heros (Forbes, 1884)
Eupomotis notatus (Large, 1903)

Potentially Misidentified Species


Lepomis cyanellus (Green Sunfish) differs from the Redar Sunfish in having a more rectangular 'bass-like' body, a large mouth, rounded pelvic fins, and dark spots on the posterior of the anal and dorsal fins. Unlike the Redear, it has dark vertical bars running down the body, and it lacks the orange or yellow breast color of the Bluegill and Pumpkinseed (Page and Burr 1991). The Green Sunfish is native to the Great Lakes-Mississippi-Gulf basins (Page and Burr 1991). It is introduced in the San Francisco estuary, and on the Atlantic Slope from South Carolina to Connecticut (USGS Nonindigenous Aquatic Species Program 2018). South of the Potomac River, it appears to be rare or absent in Coastal Plain drainages (Jenkins and Burkhead 1993).

epomis macrochirus
Lepomis macrochirus (Bluegill) resembles the Redear Sunfish with an oval 'typical-sunfish' body, a small mouth, a bright red spot on the ear-flap, and long, pointed pectoral fins. The Bluegill has a black spot on the rear edge of the dorsal fin (Page and Burr 1991). The Bluegill is native to the Atlantic Slope from North Carolina to Florida, the Great Lakes basin, and the Mississippi-Gulf basins from Quebec and Minnesota to Texas (Page and Burr 1991). It is introduced to the San Francisco and Columbia River estuaries, and widely through the western US, and on the Atlantic Slope, from northern North Carolina to Maine (USGS Nonindigenous Aquatic Species Program 2018).

Lepomis cyanellus
Lepomis cyanellus (Green Sunfish) differs from the Redear Sunfish in having a more rectangular 'bass-like' body, a large mouth, rounded pelvic fins, and dark spots on the posterior of the anal and dorsal fins. Unlike the Redear, it has dark vertical bars running down the body, but it does lack the orange or yellow breast color of the Bluegill and Pumpkinseed (Page and Burr 1991). The Green Sunfish is native to the Great Lakes-Mississippi-Gulf basins (Page and Burr 1991). It is introduced in the San Francisco estuary, and on the Atlantic Slope from South Carolina to Connecticut (USGS Nonindigenous Aquatic Species Program 2018). South of the Potomac River, it appears to be rare or absent in Coastal Plain drainages (Jenkins and Burkhead 1993).

Lepomis gibbosus
Lepomis gibbosus (Pumpkinseed) resembles the Redear Sunfish in having a deeper oval 'typical-sunfish' body, a small mouth, a bright red spot on the ear-flap, and long, pointed pectoral fins. The Pumpkinseed has thin, wavy lines on the posterior of the anal and dorsal fins (Page and Burr 1991). The Pumpkinseed is native to the Atlantic Slope from New Brunswick to South Carolina, the Great Lakes basin, and the Mississippi-Gulf basins from Manitoba to Missouri (Page and Burr 1991). It is introduced to the San Francisco and Columbia River estuaries (USGS Nonindigenous Aquatic Species Program 2018).

Lepomis gulosus
Lepomis gulosus (Warmouth) differs from the Redear Sunfish in having a more rectangular 'bass-like' body, a large mouth, and short, rounded pelvic fins. It has dark lines radiating from the prominent red eyes. The color is brown, with dark-brown mottling (Page and Burr 1991). The Warmouth is native to Atlantic drainages from the James River to Florida, and the southern Great Lakes-Mississippi-Gulf (Page and Burr 1991). It is introduced in the San Francisco and the Columbia River estuaries, and from the Rappahannock River north to the Hudson River (USGS Nonindigenous Aquatic Species Program 2018).

Ecology

General:

The Redear Sunfish (Lepomis microlophus) is a medium-sized freshwater fish, which also enters brackish water. Adults mature at 8 months (Puerto Rico), 1–2 years in Tennessee, and (possibly) 3–4 years in California, at a size of 88 (North Carolina) or 130-180 mm (California) (Hardy 1978; Moyle 2002). Spawning takes place at 22–32 °C, in freshwater (Hardy 1978; Wang 1986; Jenkins and Burkhead 1993; Moyle 2002). Males excavate and guard a nesting site in shallow water, in sand or gravel, often nesting colonially, but guarding their nests individually. Males may spawn with several females, and guard the nests until they hatch. In one study, female fish had 64,000 eggs (Froese and Pauly 2018). Eggs hatch in 1–3 days at 21–29 °C. When the yolk-sac is absorbed, the larvae leave the nest and begin feeding on zooplankton (Hardy 1978; Jenkins and Burkhead 1994; Moyle 2002). Redear Sunfish are less considered prone to early maturation and stunting than Bluegill Sunfish (Moyle 2002).

Redear Sunfish have been collected at temperatures up to 34 °C (Hardy 1978). The lower temperature has not been reported. Based on its northern range limits (to southern Illinois, Indiana, Maryland, Page and Burr1991) it probably tolerates temperatures range as low as 4 or 5 °C, but may not survive very long winters. In estuaries in the southern US, it frequently ranges into brackish water at salinities up to 10–12 PSU, and has been reported from salinities up to 20 PSU (Hardy 1978; Peterson 1988). Reported habitats include swamps, lakes, vegetated pools with mud or sand bottoms, small to medium rivers, lagoons, and bayous (Hardy 1978; Page and Burr 1991). Adults prefer deeper water than most other sunfish, below 2 m. They often feed by biting the substrate, crushing their prey, and ejecting gravel and hard parts. Young Redear Sunfish are planktivores, while adults shift to aquatic insects larvae, and amphipods, and especially, snails, which they are able to crush with specially adapted molariform teeth (Jenkins and Burkhead 1994; Winwright 1996 Fisher Huckins 1997; Moyle 2002). Common predators include larger fishes, such as bass and catfish, birds, and humans (Moyle 1997).

Food:

Mollusks, other invertebrates

Consumers:

Fishes

Competitors:

Other sunfishes

Trophic Status:

Carnivore

Habitats

General HabitatFresh (nontidal) MarshNone
General HabitatGrass BedNone
General HabitatCoarse Woody DebrisNone
General HabitatSwampNone
General HabitatNontidal FreshwaterNone
General HabitatTidal Fresh MarshNone
General HabitatSalt-brackish marshNone
General HabitatUnstructured BottomNone
Salinity RangeLimnetic0-0.5 PSU
Salinity RangeOligohaline0.5-5 PSU
Salinity RangeMesohaline5-18 PSU
Tidal RangeSubtidalNone
Vertical HabitatNektonicNone

Life History


Tolerances and Life History Parameters

Minimum Temperature (ºC)5Based on geographical range (Page and Burr 1991)
Maximum Temperature (ºC)34Hardy 1978
Minimum Salinity (‰)0This is a freshwater species.
Maximum Salinity (‰)20The maximum salinity given here, 20 PSU was a field record from Mississippi. This salinity seems high for a freshwater fish. There are numerous records from 10-12 PSU (Hardy 1978; Peterson 1988).
Minimum Length (mm)88Size at first maturity (Hardy 1978)
Maximum Length (mm)269a more usual length is 135-216 m

General Impacts

Redear Sunfish (Lepomis microlophus) are a popular pan-fish and are believed to be less prone to overpopulation and stunting than Bluegills (Dill and Cordone 1997; Jenkins and Burkhead 1993; Moyle 2002). This fish has sometimes been introduced for biocontrol of pest populations of snails in lakes (Carlander 1977). In Puerto Rico, the Redear Sunfish was found to be useful for the biocontrol of the snail Biomphalaria glabrata, a host of the blood fluke Schistosoma mansoni (Lever 1996).


Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
M090 Delaware Bay 1996 Def Estab
M130 Chesapeake Bay 1974 Def Estab
P090 San Francisco Bay 1956 Def Estab
GL-I Lakes Huron, Superior and Michigan 1928 Def Estab
GL-II Lake Erie 0 Def Estab
S050 Cape Fear River 0 Native Estab
S056 _CDA_S056 (Northeast Cape Fear) 0 Native Estab
S060 Winyah Bay 0 Native Estab
S070 North/South Santee Rivers 0 Native Estab
S080 Charleston Harbor 0 Native Estab
S090 Stono/North Edisto Rivers 0 Native Estab
S100 St. Helena Sound 0 Native Estab
S100 St. Helena Sound 0 Native Estab
S110 Broad River 0 Native Estab
S130 Ossabaw Sound 0 Native Estab
S120 Savannah River 0 Native Estab
S140 St. Catherines/Sapelo Sounds 0 Native Estab
S150 Altamaha River 0 Native Estab
S160 St. Andrew/St. Simons Sounds 0 Native Estab
S170 St. Marys River/Cumberland Sound 0 Native Estab
S175 _CDA_S175 (Nassau) 0 Native Estab
S180 St. Johns River 0 Native Estab
S183 _CDA_S183 (Daytona-St. Augustine) 0 Native Estab
S190 Indian River 0 Native Estab
S196 _CDA_S196 (Cape Canaveral) 0 Native Estab
S200 Biscayne Bay 0 Native Estab
G010 Florida Bay 0 Native Estab
G020 South Ten Thousand Islands 0 Native Estab
G030 North Ten Thousand Islands 0 Native Estab
G040 Rookery Bay 0 Native Estab
G045 _CDA_G045 (Big Cypress Swamp) 0 Native Estab
G050 Charlotte Harbor 0 Native Estab
G060 Sarasota Bay 0 Native Estab
G070 Tampa Bay 0 Native Estab
G074 _CDA_G074 (Crystal-Pithlachascotee) 0 Native Estab
G076 _CDA_G076 (Withlachoochee) 0 Native Estab
G080 Suwannee River 0 Native Estab
G078 _CDA_G078 (Waccasassa) 0 Native Estab
G086 _CDA_G086 (Econfina-Steinhatchee) 0 Native Estab
G090 Apalachee Bay 0 Native Estab
G100 Apalachicola Bay 0 Native Estab
G110 St. Andrew Bay 0 Native Estab
G120 Choctawhatchee Bay 0 Native Estab
G130 Pensacola Bay 0 Native Estab
G140 Perdido Bay 0 Native Estab
G150 Mobile Bay 0 Native Estab
G160 East Mississippi Sound 0 Native Estab
G170 West Mississippi Sound 0 Native Estab
S030 Bogue Sound 1991 Def Estab
S020 Pamlico Sound 1991 Def Estab
S010 Albemarle Sound 1991 Def Estab
G330 Lower Laguna Madre 0 Native Estab
G320 Upper Laguna Madre 0 Native Estab
G310 Corpus Christi Bay 0 Native Estab
G290 San Antonio Bay 0 Native Estab
G300 Aransas Bay 0 Native Estab
G280 Matagorda Bay 0 Native Estab
G270 Brazos River 0 Native Estab
G260 Galveston Bay 0 Native Estab
G250 Sabine Lake 0 Native Estab
G240 Calcasieu Lake 0 Native Estab
G230 Mermentau River 0 Native Estab
G220 Atchafalaya/Vermilion Bays 0 Native Estab
G210 Terrebonne/Timbalier Bays 0 Native Estab
G200 Barataria Bay 0 Native Estab
G190 Mississippi River 0 Native Estab
G180 Breton/Chandeleur Sound 0 Native Estab
S030 Bogue Sound 1973 Def Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude

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