White bass are found in many parts of central North America. Originally they only existed in the Great Lakes and the Mississippi River, but because of introductions they are now most common in the Mississippi, Missouri and Ohio rivers.

Biogeographic Regions: nearctic (Native )

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.

Biogeographic Regions: nearctic (Native )

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

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (200,000 to >2,500,000 square km (about 80,000 to >1,000,000 square miles)) This species is native to the St. Lawrence-Great Lakes, Hudson Bay (Red River), and Mississippi River basins from Quebec to Manitoba and south to Louisiana; Gulf Slope drainages from Mississippi River, Louisiana, to Rio Grande, Texas and New Mexico (Page and Burr 1991). It has been introduced widely within and outside its natural range.

Adult white bass can be as long as 46 cm (18 inches), and can weigh up to 3.2 kg (7 pounds). Females are often larger than males. White bass are silvery gray in color, and the belly is always lighter than the back. They have many narrow stripes on their sides.

Range mass: 3.2 (high) kg.

Range length: 460 (high) mm.

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry

Sexual Dimorphism: female larger

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.

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.

Range mass: 3.2 (high) kg.

Range length: 460 (high) mm.

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry

Sexual Dimorphism: female larger

Length: 42 cm

White bass prefer to live in large bodies of water, such as deep lakes and large rivers, especially above dams. They do not like muddy water or areas with many plants.

Habitat Regions: temperate ; freshwater

Aquatic Biomes: lakes and ponds; rivers and streams

• Freshwater

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.

Habitat Regions: temperate ; freshwater

Aquatic Biomes: lakes and ponds; rivers and streams

Habitat Type: Freshwater

Comments: Habitat includes open waters of large lakes and reservoirs and pools of slow-moving small to large rivers. This species usually occurs in surface waters, roaming in schools. It tends to be offshore during the day, inshore at night. It generally avoids areas of continous turbidity. Running water of tributary streams appear to be preferred for spawning, but this fish may spawn along lake shores with high wave action. Spawning substrate is usually rock or gravel bottoms in water 0.6-3 meters deep; eggs sink and stick; individuals generally return to specific spawning areas. Information primarily from Becker (1983) and Moyle (1976).

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: Yes. At least some 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.

May migrate over 200 km to upstream spawning areas, but usually not that far (Moyle 1976).

Larval white bass eat mostly zooplankton, especially Daphnia species. Juveniles eat mostly invertebrates, such as Chironomidae, Ephemeroptera, Odonata, Zygoptera, Hemiptera, Amphipoda, and Cambaridae. Adults over 350 mm in size start to eat mostly fish. Common prey includes, Pimephales promelas, Etheostoma nigrum, Dorosoma cepedianum, Dorosoma petenense, Centrarchidae, Perca flavescens, Stizostedion canadense, Aplodinotus grunniens, Cyprinus carpio, Ameiurus, and others. White bass have up to 4 peaks in daily feeding activity, but this can change throughout the year.

Animal Foods: fish; insects; aquatic crustaceans; zooplankton

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.

Animal Foods: fish; insects; aquatic crustaceans; zooplankton

Primary Diet: carnivore (Piscivore )

Comments: Visually oriented predator. Eats fishes, zooplankton, aquatic insects, oligochaetes, and crayfish; fishes often dominate diet of adults; diet may vary from place to place (Moyle 1976, Sublette et al. 1990).

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

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

Known Predators:

• white bass (Morone_chrysops)

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

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

Known Predators:

• white bass (Morone chrysops)

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

Comments: This species is represented by a large number of occurrences (subpopulations).

>1,000,000 individuals

Comments: Total adult population size is unknown but presumably exceeds 1,000,000.

Schools throughout year.

White bass use their lateral line systems to detect water movement and rely on vision and sensing chemical cues. Little is known about communication in this species.

Perception Channels: visual

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.

Perception Channels: visual

White bass eggs hatch take about two days to hatch. The young larvae quickly begin to form schools, just as adults do.

White bass eggs hatch about two days after fertilization. The young larvae quickly begin to show the schooling behavior seen in adults.

White bass grow quickly and have high death rates. Northern and southern populations have different average lifespans. 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.

Range lifespan

Status: wild: 15 (high) years.

Typical lifespan

Status: wild: 4 (low) years.

Range lifespan

Status: captivity: 9 (high) years.

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.

Range lifespan

Status: wild: 15 (high) years.

Typical lifespan

Status: wild: 4 (low) years.

Range lifespan

Status: captivity: 9 (high) years.

White bass swim to shallow water to breed. They do not build nests or form mating pairs. As a female lays her eggs, a group of males follows her, each trying to fertilize as many eggs as he can. Once the eggs are fertilized, the adults swim back to deep water.

Mating System: polyandrous

White bass breed when the water temperature reaches about 14 degrees celsius. This usually happens in February in the southern United States, and in May in the north. Each female lays around 500,000 eggs, which then sink and stick to the bottom. A group of males then fertilizes them. The eggs hatch about two days later. The young can grow to adulthood in as little as two years if they live in the south, but it can take much longer if they live in ther north.

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

Average age at sexual or reproductive maturity (male): 2 years.

Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); broadcast (group) spawning; oviparous

Average time to hatching: 2 days.

Average age at sexual or reproductive maturity (male)

Sex: male: 730 days.

Average age at sexual or reproductive maturity (female)

Sex: female: 1095 days.

Once they migrate to spawning grounds and the eggs are laid and fertilized, the adults abandon the eggs and return to deeper water.

Parental Investment: no parental involvement; pre-fertilization (Provisioning, Protecting: Female)

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.

Mating System: polyandrous

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.

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

Average age at sexual or reproductive maturity (male): 2 years.

Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); broadcast (group) spawning; oviparous

Average time to hatching: 2 days.

Average age at sexual or reproductive maturity (male)

Sex: male: 730 days.

Average age at sexual or reproductive maturity (female)

Sex: female: 1095 days.

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.

Parental Investment: no parental involvement; pre-fertilization (Provisioning, Protecting: Female)

Spawns in spring; eggs hatch in 4.5 days at 14 C, 1 day at 26 C; normally first spawns at age I to III, depending on location and conditions; few survive to age IV; forms large schools near spawning areas (Moyle 1976, Becker 1983, Sublette et al. 1990).

White bass are fairly common throughout their range, they are not listed on any conservation lists.

IUCN Red List of Threatened Species: least concern

US Federal List: no special status

CITES: no special status

State of Michigan List: no special 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.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N4 - Apparently Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Global Short Term Trend: Relatively stable (=10% change)

Comments: Warren et al. (2000) categorized the trend as "currently stable" in the southeastern United States.

Global Long Term Trend: Increase of 10-25% to decline of 30%

Comments: Abundance has increased in the lower Missouri River as a result of human-caused changes in the river (e.g, reservoir construction and consequent reductions in turbidity) (Pflieger and Grace 1987).

Comments: No major threats are known.

There are no known adverse effects of Morone_chrysops on humans.

White bass are popular with anglers and are considered good to eat.

Positive Impacts: food

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

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.

Positive Impacts: food

Comments: Sport fish, especially hybrids of white basS and striped bass in warm-water reservoirs.

Comments: Formerly placed in the genus Roccus. Electrophoretic studies indicate that distinct subpopulations may exist within even a single lake (see Lee et al. 1980). Hybrids of white bass and striped bass (called wipers) have been stocked in some areas. The family Percichthyidae was recognized by Robins et al. (1991) as possibly polyphyletic but was retained for convenience.