Like all other sunfish, family Centrarchidae, northern longear sunfish (Lepomis peltastes) are native only to North America. This species was once considered a subspecies of central longear sunfish (Lepomis megalotis), which inhabit a wide geographic range of eastern North America, stretching from southern Canada to the Gulf coast. However, northern longear sunfish are now considered their own species and are generally restricted to southern Ontario and the upper Midwest of the United States, including Minnesota, Wisconsin, Michigan, Ohio, Illinois, and Iowa. Northern longear sunfish reside in the Great Lakes and Hudson Bay drainages. (Cooper, 1983; Eddy and Underhill, 1974; Jennings and Philipp, 1992a; Jennings, 2013; Page and Burr, 1991; Scott and Crossman, 1998; Sterba, 1963)
Northern longear sunfish are temperate freshwater fish that inhabit slow-moving bodies of water ranging from headwaters of small creeks to larger rivers; they also reside in warm, shallow lakes and reservoirs. They prefer clear water over sand or gravel substrate, usually with some vegetation. Goddard and Mathis (1997) found that northern longear sunfish only inhabit Michigan lakes with marl sediment and that they avoid barren areas lacking vegetation. Their study also determined that adult longear sunfish prefer areas of lower light intensity, perhaps to avoid predators rather than simply seeking shelter in vegetation. Another study by Schaefer et al. (1999) revealed that longear sunfish were more common at depths less than 45 cm and rare at depths greater than 90 cm. Longear sunfish are not very tolerant of turbid water, which makes them a good indicator species for pristine clear water conditions. (Becker, 1983; Cooper, 1983; Goddard and Mathis, 1997; Page and Burr, 1991; Schaefer, et al., 1999; Scott and Crossman, 1998; Scott, 1967; Smith, 1979; Sterba, 1963; Trautman, 1957)
Northern longear sunfish have a long opercular flap, which looks like a fish’s ear, hence the name “longear”. Males have longer opercular flaps than females, which is thought to be a result of sexual selection. The body is short, deep, and laterally compressed and they have ctenoid scales. As any centrarchid, northern longear sunfish have a split dorsal fin that is joined at the base, resembling a single dorsal fin. The anterior dorsal fin generally has 10 to 11 spines, while the posterior dorsal fin has 10 to 12 soft rays. They also have short, rounded pectoral fins and an anal fin with a spine preceding several soft rays. Adult longear sunfish are generally rusty brown on the dorsal surface and bright orange on the ventral surface. They have vibrant wavy blue lines on their cheeks and operculum, which is black and oriented horizontally. The fins are clear to yellow and orange. The colors and patterns are intensified in breeding males. Males are also slightly larger than females. Young northern longear sunfish look somewhat different than adults. They tend to have a smaller opercular flap that is tilted 45°, and they usually have a paler coloration. Young fish are olive-brown on the dorsal surface with a pale red, orange, or yellow ventral surface. Their sides and head are speckled with orange, yellow, and green. They have orange cheeks with wavy blue streaks stretching from the mouth to the eye. Northern longear sunfish look very similar to central longear sunfish with some minute discrepancies. They are smaller than central longear sunfish, growing to a maximum of 12 cm as opposed to 20 cm. This smaller body size may be the consequence of a tradeoff for earlier maturation and greater reproductive effort. Adult males also appear to retain more juvenile characteristics than central longear sunfish, which is a phenomenon known as paedomorphism. For instance, their opercular flap is smaller and slanted at 45°, rather than horizontal. In addition, northern longear sunfish have a single, large reddish-orange spot on the posterior of the operculum, whereas central longear sunfish have white around the operculum with small red spots. Adult male northern longear sunfish also have 8 to 12 defined vertical blue stripes on their sides. The stripes on the female's sides are more prominent than those of central longear sunfish. (Becker, 1983; Cooper, 1983; Eddy and Underhill, 1974; Jennings and Philipp, 1992b; Page and Burr, 1991; Scott and Crossman, 1998; Scott, 1967; Smith, 1979; Trautman, 1957)
Female longear sunfish lay pale yellow eggs 1 mm in diameter, which stick to the substrate in which they are nested. The larvae hatch approximately 3 to 5 days after fertilization. Several days later, the young develop the ability to swim and disperse from the nest. (Scott and Crossman, 1998)
Longear sunfish have a polyandrous mating system, which means females mate with more than one male in a given season. Females preferentially mate with larger males because males are responsible for the parental care; therefore, females use size as a proxy for ability to nurture offspring. Male opercular flaps also seem to function as sexual ornaments for female choice. Females tend to mate with males that have longer opercular flaps, which may reflect a male’s ability to compete with other males and control resources. Male longear sunfish exhibit two reproductive strategies. The majority of males construct nests in colonies, with larger males securing prime nesting grounds in the center of the colony. Females seem to preferentially mate with larger males at the center. Thus, it would seem that a colonial nesting strategy would negatively affect smaller males because they would be out-competed by the larger males; however, females may mate with smaller males on the perimeter after mating with a larger male since it is more convenient than spending effort to search for other large males. Colonial nesting also enables smaller males to take advantage of their bigger competitors by intruding into their nests during mating. By sneaking into the nest during spawning, smaller males have a chance to fertilize some of the eggs without having to build their own nest. In addition, some of the larger males build a solitary nest, which reduces male-male competition and the probability of cuckolding. This solitary strategy is just as successful as the strategy employed by colonial males. Longear sunfish reproduce by external fertilization. During spawning, males spend one to two days using their tails to fan out a shallow nest in the sand or gravel, in water 12 to 50 cm deep. Mature females enter a male’s nest and the pair circles within the nest, swimming side by side. Every 15 seconds or so, the female tilts her body at an angle and shudders, releasing eggs, while the male remains upright and shudders, releasing sperm. The eggs are fertilized by the sperm as they fall into the nest. Subsequently, the male chases the female away from the nest and she never returns. (Becker, 1983; Bietz, 1981; Dupuis and Keenleyside, 1988; Goddard and Mathis, 2000; Jennings and Philipp, 1992c; Keenleyside, 1972; Scott and Crossman, 1998; Scott, 1967; Witt, Jr. and Marzolf, 1954)
Northern longear sunfish are iteroparous, meaning they breed multiple times throughout their lives. Both males and females become sexually mature between two and four years of age; however, males generally mature earlier than females. Jennings and Philipp (1992) found that sneaker males can become mature at just one year of age. Longear sunfish breed five to six times per breeding season, which extends from June through August when the temperature is at least 20° C. However, according to Jennings and Philipp (1994), cooler water temperatures could cause northern longear sunfish to start spawning later, which could decrease the chances of offspring surviving through the winter. Each spawning period lasts two to three days. Keenleyside (1972) observed that spawning frequency increases throughout the day, reaching a maximum in the afternoon when the water is warmest. Like most fish, longear sunfish are oviparous, with females depositing anywhere from 2,000 to 22,000 eggs during each spawning period. Young hatch two to five days after fertilization. The number of larvae that hatch varies from 50 to 1,000 individuals. Within a week or two of hatching, the larvae are capable of swimming and leave the nest in search of food, never to return. (Becker, 1983; Cooper, 1983; Cross and Collins, 1975; Dupuis and Keenleyside, 1988; Jennings and Philipp, 1992c; Jennings and Philipp, 1992b; Jennings and Philipp, 1994; Keenleyside, 1972; Scott and Crossman, 1998; Trautman, 1957)
Northern longear sunfish provide intensive parental care to their offspring, which is only contributed by males. Males are incredibly territorial and aggressive when defending their nests. During spawning, males drive out intruders that attempt to eat the eggs before fertilization. As soon as spawning is complete, males chase away the female and return to the nest to guard the eggs. They immediately begin fanning their tails over the eggs to ensure a constant supply of oxygen. Males continue to guard the nest until the fry are capable of swimming and finding their own food. Witt and Marzolf (1954) observed longear sunfish defending the nest against bottom-feeding fishes, but not surface-feeding fishes, which suggests that males can distinguish potential predators from non-threatening fishes. Males will desert the nest if the expected fitness returns are low or in the event of flooding. (Becker, 1983; Cooper, 1983; Eddy and Underhill, 1974; Jennings and Philipp, 1992c; Jennings and Philipp, 1994; Keenleyside, 1972; Page and Burr, 1991; Scott and Crossman, 1998; Scott, 1967; Sterba, 1963; Witt, Jr. and Marzolf, 1954)
Northern longear sunfish are typically expected to live a maximum of six years in the wild. However, the maximum recorded age of northern longear sunfish seems to be around eight years old. No information could be found on their lifespan in captivity. (Scott and Crossman, 1998; Smith, 1979)
Longear sunfish are diurnal; they do most of their feeding during the day. They are relatively inactive throughout the night, but especially at dawn and dusk. This is thought to be an avoidance strategy since predators, such as black bass, tend to actively feed at those times. However, longear sunfish have been known to feed during late summer nights when the moon is bright. Males are territorial and quite aggressive. They defend their territories by rushing towards intruding fish. Goddard and Mathis (2000) observed an unusual amount of mouth wrestling among males, which is an agonistic behavior performed to establish dominance. Not only do they compete for mates, but also for food. Longear sunfish establish dominance hierarchies that are based mostly on body size. This seems to result in smaller, juvenile fish occupying deeper littoral habitats and larger, mature fish inhabiting the shallowest water near shore. There also appears to be sexual segregation within the species due to size differences as well. Although they are colonial nesters, there is no information about the sociality of northern longear sunfish. (Becker, 1983; Goddard and Mathis, 1997; Goddard and Mathis, 2000; Kwak, et al., 1992; Laughlin and Werner, 1980; Scott and Crossman, 1998; Witt, Jr. and Marzolf, 1954)
Northern longear sunfish have a limited home range of 30 to 70 m. The length of the home range is especially limiting during spawning season when males must protect their offspring. Older fish have larger home ranges. (Gunning and Shoop, 1963; Smith, 1979)
Since longear sunfish are diurnal and actively feed during the day, it is likely that their vision is quite developed. They also appear to have a well-developed sense of smell. Gunning and Shoop (1963) proposed that longear sunfish use olfactory cues as a means to identify and locate their home range. In addition, longear sunfish are capable of acoustic and auditory communication and perception. During spawning season, when a male sees a female, he approaches her and produces grunting sounds to entice her into his nest. It is not known whether females produce similar noises, but, according to Gerald (1971), it is possible that they also grunt to attract the attention of males. Longear sunfish also use visual displays to communicate with conspecifics as well as predators. For example, bright coloration in a male may be an indication to females that he is ready to breed. Males also appear to use their opercular flaps to communicate with other males in competition. They flash each other laterally to show off their opercular flaps, which signal their ability to compete for and hold resources, without engaging in physical combat. Whenever they feel threatened, longear sunfish assume an aggressive posture, which includes extending their fins and opercles and opening their mouths. (Gerald, 1971; Goddard and Mathis, 2000; Gunning and Shoop, 1963; Jennings and Philipp, 1992b; Kwak, et al., 1992; Witt, Jr. and Marzolf, 1954)
Longear sunfish generally feed during the day and eat a wide variety of foods. They feed primarily on insects at the surface, the majority of which are midges, but also dragonfly nymphs, mayfly nymphs, and mayflies, which can also be found in the sediment. Micro-crustaceans, fish eggs (including those of its own species), and amphipods also can comprise a large portion of their diet. Mid- and large-sized fish occasionally eat small amounts of terrestrial foods, detritus, algae, mollusks, crustaceans, bryozoans, mites, snails, and leeches. Some larger individuals even eat other fish, such as young bass and newly hatched sunfish. (Becker, 1983; Cooper, 1983; Cross and Collins, 1975; Scott and Crossman, 1998; Scott, 1967; Shoup and Hill, 1997; Trautman, 1957)
Largemouth bass are the major aquatic predator of longear sunfish. When large bass approach, sunfish usually flee for cover, even deserting their nests. Longear sunfish are also in danger of avian predators, such as wading birds. Like other members of family Centrarchidae, longear sunfish prefer low light and areas with cover as opposed to brighter light intensity and exposed areas. However, adult longear sunfish prefer low light intensity over vegetative cover, suggesting that they would rather hide from predators in the darkness than in vegetation. Conversely, juvenile longear sunfish seem to prefer hiding from predators in submerged vegetation. Many fishes prey upon longear sunfish eggs during the breeding season, including female conspecifics. However, their major egg predators are sucker species (family Catostomidae), which swim slowly along the bottom, eating eggs and fry and destroying nests. Male aggression against such nest intrusions may depend on the age of the eggs or fry. If the eggs were laid recently, male sunfish are more likely to drive the suckers away with aggressive behavior; if the eggs or fry are older, male sunfish are less aggressive and allow the suckers to invade the nest. Cyprinids have also been seen feeding on sunfish eggs in abandoned nests. Male longear sunfish appear to recognize that bottom-feeding fishes are more of a threat to their eggs than surface-feeding fishes, and thus concentrate their defenses against them. (Becker, 1983; Goddard and Mathis, 1997; Keenleyside, 1972; Mueller, 1980; Witt, Jr. and Marzolf, 1954)
In general, sunfish are a key component to freshwater ecosystems. They are on an intermediate trophic level that links upper and lower levels, since they are both predators and prey. (Goddard and Mathis, 1997)
Longear sunfish are not especially economically important to humans. They are too small to be considered a desired game species or to be commercially important. However, they easily adapt to life in aquaria, so they are a good laboratory species for experiments, and can also potentially be kept as pets. (Becker, 1983; Cross and Collins, 1975)
No information could be found that suggested longear sunfish have a negative impact on humans or the economy.
Longear sunfish are not considered endangered or threatened, federally or internationally. Likewise, none of the states that northern longear sunfish inhabit list the species as endangered or threatened.
Longear sunfish are known to hybridize with bluegill, green sunfish, and orange-spotted sunfish. Jennings and Philipp (1992) suggested that northern longear sunfish may have diverged from central longear sunfish about 10,000 years ago, at the end of the last Wisconsin glaciation. Northern longear sunfish occur in small populations, which have less genetic variability than populations of their southerly congeners, possibly as a result of genetic drift or repeating founder events as glaciers melted. Jennings and Philipp (1992) also proposed that the rapid morphological differentiation between the two subspecies is likely due to reproductive isolation, mating preferences, and sexual selection. (Jennings and Philipp, 1992a; Scott and Crossman, 1998)
Mandy Bromilow (author), University of Michigan-Ann Arbor, Lauren Sallan (editor), University of Michigan-Ann Arbor, Jeff Schaeffer (editor), University of Michigan-Ann Arbor, Leila Siciliano Martina (editor), Animal Diversity Web Staff.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
uses sound to communicate
an animal that mainly eats meat
uses smells or other chemicals to communicate
used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.
particles of organic material from dead and decomposing organisms. Detritus is the result of the activity of decomposers (organisms that decompose organic material).
ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
fertilization takes place outside the female's body
union of egg and spermatozoan
mainly lives in water that is not salty.
An animal that eats mainly insects or spiders.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
parental care is carried out by males
the area in which the animal is naturally found, the region in which it is endemic.
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
the business of buying and selling animals for people to keep in their homes as pets.
Referring to a mating system in which a female mates with several males during one breeding season (compare polygynous).
breeding is confined to a particular season
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
uses sight to communicate
animal constituent of plankton; mainly small crustaceans and fish larvae. (Compare to phytoplankton.)
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