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Morone chrysopsBass

By Tyler Morgan

Geographic Range

Morone chrysops (white bass) can be seen in many parts of North America. Its range extends from southern Canada to northeastern Mexico following a path roughly between the Mississippi River system and the Appalachian Mountains. Notable abundance of the species is located primarily in the Mississippi, Missouri, and Ohio River drainages. Historically, it was found only in the Great Lakes and Mississippi River drainages, but it has been widely introduced outside of these areas. (Etnier and Starnes, 2001; Quist, et al., 2002)

Habitat

White bass are principally found in large bodies of water (i.e., deep lakes and unmuddied rivers). Reservoir systems have been shown to house higher populations compared to natural lakes and rivers. This species prefers areas of open water with little turbidity and where the substrate is clean and unvegetated. Lower abundances of white bass have shown to be in direct correlation with increasing amounts of vegetation. ("Aquatic Habitat Assessment", 2005; Etnier and Starnes, 2001; Quist, et al., 2002; Walden, 1964)

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams

Physical Description

The maximum length of Morone chrysops is about 46 cm (18 inches) and the maximum weight reaches around 3.2 kg (7 pounds). White bass are silvery gray fish with the belly and breast region being lighter (silver to white) and the dorsal region silver to black in color. They exhibit numerous narrow, uninterrupted, dark colored lines along their sides which are sometimes incomplete below the lateral line. They have a protruding lower mandible and the mouth extends to the middle of the eye. White bass have been recorded to be around 212 mm total length at one year, 364 mm at two years, 401 mm at three, and 426 mm at four. Females become larger than males on average. (Etnier and Starnes, 2001)

Characteristics that enable more precise identification of the species include a lateral line count of 51 to 60 scales. Dorsal fin rays number 12 to 14 anal fin rays 11 to 13. This species has 20 to 25 gill rakers and its pectoral fins have 15 to 17 fin rays. Near the tip of the tongue, white bass have a noticeable tooth patch that lies in one fused or two barely separate areas of the tongue. (Etnier and Starnes, 2001)

  • Sexual Dimorphism
  • female larger
  • Range mass
    3.2 (high) kg
    7.05 (high) lb
  • Range length
    460 (high) mm
    18.11 (high) in

Development

White bass eggs hatch about two days after fertilization. The young larvae quickly begin to show the schooling behavior seen in adults. (Etnier and Starnes, 2001; Walden, 1964)

Reproduction

River-dwelling white bass migrate upstream in search of tributaries to spawn, while lake-dwelling individuals search out stream inlets and shoreline to lay their eggs. As a female disperses her eggs, many males follow behind releasing their sperm with the intention of fertilizing as many of the eggs as possible. No elaborate courtship displays are practiced and no nests are built. Once spawning has taken place, breeding individuals return to deeper water. (Etnier and Starnes, 2001; Walden, 1964)

Spawning of Morone chrysops occurs as early as mid-February in the southern United States and as late as May in the more northern latitudes, or whenever water temperatures reach about 14-20 degrees celsius. White bass are polyandrous, and each female can lay up to and even over half a million eggs. Once the adhesive eggs are laid, they settle to the bottom and attach to the substrate to await fertilization by the males. Hatching occurs about 2 days after fertilization, with growth of the young being quite rapid. Sexual maturity is reached around 2 years after hatching in more southerly populations, while northern populations can take a significantly longer time to mature. (Etnier and Starnes, 2001; Gilbert and Williams, 2002; Guy, et al., 2002; Quist, et al., 2002)

  • Breeding interval
    White bass annually breed in the spring
  • Breeding season
    Spawning occurs from March through May
  • Range number of offspring
    Up to 100's of thousands (high)
  • Average time to hatching
    2 days
  • Average time to hatching
    2 days
    AnAge
  • Average age at sexual or reproductive maturity (female)
    2 years
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    1095 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    2 years
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    730 days
    AnAge

White bass do not invest parental care beyond laying the eggs. Once they migrate to spawning grounds and the eggs are laid and fertilized, the adults abandon the eggs and return to deeper water to leave their offspring forcing them to fend for themselves. (Etnier and Starnes, 2001; Walden, 1964)

  • Parental Investment
  • no parental involvement
  • pre-fertilization
    • provisioning
    • protecting
      • female

Lifespan/Longevity

Morone chrysops exhibits rapid growth in conjunction with high natural mortality, resulting in a relatively short life. Although maturity is fairly similar in northern and southern populations, lifespan is not. Northern fish, on average, live longer than southern fish. Typically, southern white bass live about 4 years while northern white bass can live 8 years. Some white bass have reached 14 years of age. (Etnier and Starnes, 2001; Guy, et al., 2002; Willis, et al., 2002)

  • Range lifespan
    Status: wild
    15 (high) years
  • Typical lifespan
    Status: wild
    4 (low) years
  • Range lifespan
    Status: captivity
    9 (high) years
    AnAge

Behavior

White bass are social, they can be found traveling in dense schools in areas of open water. Schools of white bass can be seen near the surface ravenously feeding during certain times of the day, while at other times schools are found at depths in excess of 30 feet. Schools are made up of individuals of about the same age, with larger schools containing more younger fish. (Etnier and Starnes, 2001; Gilbert and Williams, 2002; Walden, 1964)

Home Range

No information on home range size was found but fish have been documented traveling large distances. A tagged fish was once recovered in Missouri that had traveled over 40 miles. White bass in Lake Erie have been documented traveling throughout the entire lake. (Walden, 1964)

Communication and Perception

White bass use their lateral line systems to detect water movement and rely on vision and sensing chemical cues. Little is known about interspecific communication in this species. (Etnier and Starnes, 2001; Etnier and Starnes, 2001)

Food Habits

Larval white bass feed mostly on zooplankton, especially Daphnia species. As development proceeds, juveniles begin feeding on macro-invertebrates, such as chironomid larvae (Chironomidae), mayfly larvae (Ephemeroptera), dragonfly larvae (Odonata), damselfly larvae (Zygoptera), bugs (Hemiptera), amphipods (Amphipoda), and crayfish (Cambaridae). Adults, or fish over 350 mm, become highly piscivorous and begin feeding upon fish. Common prey includes, fathead minnows (Pimephales promelas), johnny darters (Etheostoma nigrum), gizzard shad (Dorosoma cepedianum), threadfin shad (Dorosoma petenense), young sunfish (Centrarchidae), yellow perch (Perca flavescens), saugers (Sander canadensis), freshwater drum (Aplodinotus grunniens), carp (Cyprinus carpio), bullhead species (Ameiurus), and others. When feeding, schools of white bass prey upon schools of feeder fish (various shad and minnow), causing the small, feeder fish to splash wildly at the surface as they try to escape. Anglers calle this the "jumps." Up to 4 peaks in daily feeding activity can occur, but this varies seasonally. (Etnier and Starnes, 2001; Guy, et al., 2002)

  • Animal Foods
  • fish
  • insects
  • aquatic crustaceans
  • zooplankton

Predation

White bass are easily preyed upon by many carnivorous fish species, including other white bass. (Schultz, 2004)

  • Known Predators
    • white bass (Morone chrysops)

Ecosystem Roles

White bass are important as intermediate predators in the ecosystems in which they live, they are food for larger fish and other predators.

Economic Importance for Humans: Positive

There is renewed angling interest in white bass. Their vigor when hooked has led to increasing popularity. They are also a popular food for consumption. (Etnier and Starnes, 2001; Guy, et al., 2002; Willis, et al., 2002)

  • Positive Impacts
  • food

Economic Importance for Humans: Negative

There are no known adverse effects of Morone chrysops on humans.

Conservation Status

Not listed on any conservation lists, white bass are abundant where they occur. Unlike other species that may have minimum size limits and creel limits, many states do not impose size or creel limits for white bass caught inside their waterways. Of the states that do impose creel limits, they are typically very liberal. One potential problem with white bass populations is high variation of recruitment from year to year. The problem seems to revolve around the amount of precipitation for that year, but this has not been confirmed. (Etnier and Starnes, 2001)

Contributors

Tanya Dewey (editor), Animal Diversity Web, Mary Hejna (editor), University of Michigan-Ann Arbor.

Tyler Morgan (author), Eastern Kentucky University, Sherry Harrel (editor, instructor), Eastern Kentucky University.

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

ectothermic

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

external fertilization

fertilization takes place outside the female's body

fertilization

union of egg and spermatozoan

food

A substance that provides both nutrients and energy to a living thing.

freshwater

mainly lives in water that is not salty.

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.

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.

nomadic

generally wanders from place to place, usually within a well-defined range.

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

polyandrous

Referring to a mating system in which a female mates with several males during one breeding season (compare polygynous).

seasonal breeding

breeding is confined to a particular season

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.

tactile

uses touch to communicate

temperate

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).

visual

uses sight to communicate

zooplankton

animal constituent of plankton; mainly small crustaceans and fish larvae. (Compare to phytoplankton.)

References

2005. "Aquatic Habitat Assessment" (On-line). American Fisheries Society. Accessed October 16, 2005 at http://www.fisheries.org/html/publications/bookpdf/aquaticmethods.pdf.

Etnier, D., W. Starnes. 2001. The Fishes of Tennessee. Knoxville: The University of Tennessee Press.

Gilbert, C., J. Williams. 2002. National Audubon Society Field Guide to Fishesl. New York, United States: Alfred A. Knopf, Inc..

Guy, C., R. Schultz, M. Colvin. 2002. Ecology and Management of White Bass. North American Journal of Fisheries Management, Volume 22 Issue 2: 606-608.

Hartman, K. 1998. Diets of White Bass in the Ohio Waters of Lake Erie during June–October 1988. American Fisheries Society, Volume 127: 323-328. Accessed November 24, 2005 at http://afs.allenpress.com/perlserv/?request=get-document&issn=1548-8659&volume=127&issue=2&page=323.

Quist, M., C. Guy, R. Bernot, J. Stephen. 2002. Ecology of larval White Bass in a large Kansas Reservoir. North American Journal of Fisheries Management, Volume 22 Issue 2: 637-642.

Schultz, K. 2004. Field Guide to Freshwater Fish. Hoboken, New Jersey: John Wiley & Sons, Inc..

Walden, H. 1964. Familiar Freshwater Fishes of America. New York, NY: Harper & Row, Publishers, Inc..

Willis, D., C. Paukert, B. Blackwell. 2002. Biology of White Bass in Eastern South Dakota Glacial Lakes. North American Journal of Fisheries Management, Volume 22 Issue 2: 627-636.

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