Esox americanus

Geographic Range

Esox americanus is found throughout many large river drainages from the Midwest to the Atlantic coast of North America, and from southern Canada to the southern United States. Some of the large Rivers this species is found in are the Mississippi, Ohio, Brazos, and Tennessee Rivers. An Atlantic coast form of the species is found from New York to Georgia and in eastern drainages. Another group, which are intergrades of the two subspecies, are found in the Gulf Coast Drainages in Alabama, Florida and southwestern Georgia.

Habitat

This species is most often found in clear lakes and slow to moderate running streams, but can also be found in overflow pools and marshes. Their habitat includes dense aquatic vegetation and bottoms with organic matter. The preferred temperature of this fish is 26° C. The highest population densities are found in shallow weedy areas with lots of vegetation including leafy liverworts, water lilies, filamentous algae, pondweeds, and cattails (Wallus, et al., 1990).

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams

Physical Description

This fish is an esocid. It has fully scaled cheeks and gill covers, and the top of the head has few or no scales. A darkened backward slanting vertical bar is present beneath the eyes. The dorsal side is dark green to brown, and the ventral side is cream or yellow. The color patterns on the lateral sides is variable, from a green and white brick wall pattern to forward slanting vertical bars (Mettee, et al., 1996). E. americanus can occasionally grow longer than 12 inches (Florida Fish and Wildlife, 2000).

  • Sexual Dimorphism
  • sexes alike

Reproduction

Depending on the location of the fish, spawning will take place anywhere from late February to early May, with fish in warmer climates spawning earlier than those in colder climates. E. americanus is one of the earliest spawning fishes in the spring. To spawn, the fish migrate from large rivers and lakes into small streams. Spawning temperature has been estimated at anywhere from 4°C to 18.3°C (Wallus, et al., 1990).

The act of spawning occurs with one female and several males. Eggs and milt are ejected by sudden lashings of the caudal fin. Eggs are broadcast over aquatic vegetation, moss, leaves, twigs, and in temporary floodplains, marshes and shallow pools (Wallus et al., 1990). The incubation period of the eggs lasts from 11 to 15 days, longer incubation is needed for eggs to mature in colder water. (Wallus, et al., 1990)

Behavior

Young live in schools while adults are solitary, predaceous, and aggressive, only coming together to spawn (Mettee, 1996). (Mettee, et al., 1996)

Communication and Perception

Food Habits

E. americanus is a predator that as an adult feeds on large insect larvae, crayfishes and other fishes. This fish does not move a great deal to hunt for food. Instead it camouflages itself and waits for unsuspecting prey. When it has the prey located, it will dart out of hiding quickly, grasp the prey and swallow it head first (Mettee, et al., 1990). Newly hatched larvae feed on larvae of later spawning species.

  • Animal Foods
  • fish
  • insects
  • aquatic crustaceans

Predation

Economic Importance for Humans: Positive

It can be fun to fish for Esox americanus, but because they do not grow very large, they are not popular as a sport fish. The meat from these fish is white, flaky, and sweet, but bony (Florida Fish and Wildlife, 2000).

Conservation Status

Esox americanus is a common species with a wide geographic range. It is not threatened or endangered.

Other Comments

There are two subspecies of E. americanus. They are E. americanus americanus, commonly known as the redfin pickerel, and E. americanus vermiculatus, known better as the grass pickerel. These subspecies are very similar and do breed together where their ranges overlap. Redfin pickerel live to six years, and grass pickerel live to seven years (Mettee, 1996).

Contributors

William Fink (editor), University of Michigan-Ann Arbor.

Sera Coppolino (author), University of Michigan-Ann Arbor.

Glossary

Nearctic

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.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

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).

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

piscivore

an animal that mainly eats fish

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

solitary

lives alone

tactile

uses touch to communicate

References

Florida Fish and Wildlife Conservation Commission, "Pickerel" (On-line). Accessed November 10, 2000 at http://www.state.fl.us/gfc/fishing/Fishes/pickerels.html.

Mettee, M., P. O'Neil, J. Pierson. 1996. Fishes of Alabama and the Mobile Basin. Birmingham, Alabama: Oxmoor House.

Wallus, R., T. Simon, B. Yaeger. 1990. Reproductive Biology and Early Life History of Fishes in the Ohio River Drainage. Volume 1: Acipenseridae through Esocidae. Chattanooga, Tennessee: Tennessee Valley Authority.