Ictiobus cyprinellus

Geographic Range

Bigmouth buffalo ( Ictiobus cyprinellus ) are native to much of North America. Within Canada, their range extends from Manitoba to Saskatchewan. These fish exhibit a broad distribution in the United States, ranging from Montana to Ohio, south to Alabama, and west to Texas. Additionally, the species has invaded the Great Lakes region, which most likely resulted from bigmouth buffalo movement through the Wisconsin-Fox Canal to the Lake Michigan drainage. These fish are also non-indigenous to reservoirs in Arizona, North Dakota, and Montana, as well as in aqueduct systems in southern California, where intentional stocking and escape from fish hatcheries has enabled their proliferation.

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

Bigmouth buffalo inhabit a broad range of freshwater habitats. Most frequently, they occupy slow moving channels or oxbows in rivers, where regular spring floods provide spawning habitat. However, bigmouth buffalo are also capable of surviving in inland lakes and reservoirs. During the summer, this species migrates into warm, shallow bays of the upstream portion of reservoirs, while seeking deeper water in the fall and winter. While inherently a benthic, deep water species, bigmouth buffalo may be partially pelagic. This species is quite tolerant of low oxygen concentrations and high water temperatures. Likewise, their tolerance for suspended sediment is high, with a preference for muddled waters of over 100 ppm turbidity. This species prefers waters of low velocity current [0 - 70 cm/sec], yet they can withstand higher velocities for brief periods of time. A habitat with a pH range of 6.5 to 8.5 is optimal for bigmouth buffalo.

• Habitat Regions
• temperate temperate
• freshwater freshwater

• Aquatic Biomes
• pelagic pelagic
• benthic benthic
• lakes and ponds
• rivers and streams

Physical Description

Bigmouth buffalo are the largest members of the Catostomidae , or "sucker" family. This species acquired its name from its terminal, oblique mouth, which is comprised of large, wide lips, with the upper lip almost level with the eyes. These fish have a robust, elliptical body, with an anteriorly upward curved ventral line. In contrast to smallmouth buffalo , bigmouth buffalo do not have an arched or ridge-like back. Additionally, the terminal mouth of bigmouth buffalo can be differentiated from smallmouth buffalo, which possess a subterminal, downward facing mouth like most other suckers. Bigmouth buffalo possess anterior fin rays, anal fin rays, pelvic fin rays, and a sickle-shaped dorsal fin that extends from the midway of the back to the tail. They have cycloid scales, and exhibit a range of coloration, from bronze to a dark olive brown, with lighter shades on their sides and belly. This species possesses a Webarian apparatus, in which the first four vertebrate are highly modified, connecting their swim bladder to their auditory system. Large, forked inter-muscular bones make up the anterior dorsal musculature. Bigmouth buffalo develop a single row of weak, short pharyngeal teeth, and jaw arches that are typically thin and fragile.

• Other Physical Features
• bilateral symmetry bilateral symmetry

Development

Bigmouth buffalo eggs, which average 1.5 mm in diameter, are released throughout the months of April and June. Hatching success is decreased by heightened turbidity and dramatic changes in the water level. The eggs are openly released into the water before adhering to nearby vegetation or floating objects. Once eggs are released, they receive no further attention, requiring 8 to 14 days for incubation, although this is dependent on the water temperature. Hatching occurs at about 17°C. Young individuals tend to gather in shallow bays, feeding on both animal and plant forms of plankton. Toward the beginning of their first fall, the juveniles reach approximately 102 to 152 mm, as juvenile growth proceeds rapidly. However, in the following years, the species displays a progressive decline in growth rate with increasing age.

Reproduction

During spawning periods, males develop temporary breeding tubercles over the majority of their body surface, making the distinction between sexes readily apparent. Females do not possess tubercles, but have a thicker body and an enlarged vent. Bigmouth buffalo are group spawners, with one specific breeding area supporting 3 to 30 spawning units that reproduce simultaneously, with 3 to 5 fish per unit. These individual spawning units are commonly comprised of one female, the center of the spawning unit, and a range of 2 to 4 males. When the female is prepared to deposit her eggs, she sinks to the bottom. Subsequently, the males of her unit surround her, pushing the female upwards to the water surface. These males create a large rush in which reproductive milt is released, colloquially called "tumbling". Females concurrently create large, rushing wakes at the water surface, combined with large, loud splashes from the thrashing of their tails. This mating practice mixes female eggs and male milt together. The resulting fertilized eggs are free to float within the water column, before attaching to floating vegetation with their adhesion.

• Mating System
• polyandrous polyandrous

Bigmouth buffalo spawning is stimulated by spring flooding, typically following a series of warm calm nights. Ideally, spawning commences in water temperatures between 18 and 24°C, where night temperatures seldom drop below 12.8°C. The necessity of these conditions suggests that reproduction may be delayed until a more adequate environment has developed. When environmental conditions are sufficient, these fish migrate upstream to find shallow embayments of dense vegetation. Flooded marshes with clean, clear water are the preferred breeding grounds. The breeding period is relatively short, with reproducing adults typically remaining on the spawning ground for a single day. Mere hours after spawning, the fish return from the spawning floodplains to their native mainstream channels, completing a return journey of approximately 0.8 to 1.6 kilometers.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• fertilization fertilization
  • external external
• broadcast (group) spawning
• oviparous oviparous

Females may produce approximately 100,000 eggs per pound of body weight. No nest site is prepared by parent fish, nor is any parental care given.

• Parental Investment
• no parental involvement

Lifespan/Longevity

Slower growth and longer lifespans are typically found within Canadian populations due to shorter growing seasons. Females typically mature at lengths greater than 475 mm; males mature at lengths of about 356 mm. The oldest known wild individual survived to be 20 years, however, the average wild lifespan is about 3 years. Individuals housed in captivity generally live 6 to 8 years.

Behavior

Throughout most of their lives, bigmouth buffalo commonly school near the middle of the water column or along the bottom of larger slow-moving rivers.

• Key Behaviors
• natatorial natatorial
• motile motile
• sedentary sedentary
• social social

Home Range

These fish make spawning journeys of 0.8 to 1.6 km from their native mainstream channels to the spawning floodplains.

Communication and Perception

Bigmouth buffalo seek food by using their senses of touch, taste, and sight.

• Communication Channels
• visual visual
• tactile tactile
• chemical chemical

• Perception Channels
• visual visual
• tactile tactile
• chemical chemical

Food Habits

Zooplankton are the most important food source within the diet of bigmouth buffalo. However, this species also consumes small crustaceans , benthic insect larvae, phytoplankton, and detritus. These fish may also be able to survive on periphyton, which is a mixture of algae , microbes, and detritus attached to sediment. This species is known as an 'effective vacuum cleaner', deriving much of its food from benthic rocks, plants, and the water itself. Their diet does not change with water column depth, age, or size.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore
  • eats non-insect arthropods
  • molluscivore molluscivore
• herbivore herbivore
  • algivore
• omnivore omnivore
• planktivore planktivore
• detritivore detritivore

• Animal Foods
• insects
• mollusks
• zooplankton zooplankton

• Plant Foods
• algae
• phytoplankton phytoplankton

• Other Foods
• detritus detritus

• Foraging Behavior
• stores or caches food stores or caches food
• filter-feeding filter-feeding

Predation

Rapid juvenile growth and the large mass of adult bigmouth buffalo suggest they have few natural predators. However, small bigmouth buffalo may serve as forage for larger sport fish.

Ecosystem Roles

Bigmouth buffalo provide an important function in the lower levels of the aquatic food chain, consuming a wide variety of crustaceans and insects as well as controlling zooplankton growth. Their ability to digest algae and detritus also aids in decomposition and nutrient cycling within their ecosystems.

• Ecosystem Impact
• biodegradation biodegradation

Economic Importance for Humans: Positive

In the lower Mississippi River Basin, bigmouth buffalo are considered a popular food fish, providing the basis for a large commercial fishery. These fish possess many desirable nutritional benefits including high protein content and low cholesterol; in addition, the meat may be refrigerated for long periods of time without drastic degradation. As polyculture candidates, bigmouth buffalo can be a good choice; as plankton and detritus feeders, they require minimal outside feeding in intensely utilized culture ponds. Furthermore, once hooked, bigmouth buffalo put up a dazzling fight. This indicates that the species possesses the potential to one day enhance their status to the level of sport fishes. Avid supporters of bigmouth buffalo in Wisconsin have claimed the species is "the musky of the southern Wisconsin streams, the sportiest, wariest, most mysterious and most sought-after native fish that swims, and, when smoked, a supreme gourmet’s delight”. Angling these fish using rods and reels is rarely successful. However, some anglers have succeeded in catching bigmouth buffalo using small hooks hidden in dough balls, positioned near the water bottom. Furthermore, bows and arrows, crossbows, snares, gigs, spears, and spear guns are functional methods of capturing bigmouth buffalo.

• Positive Impacts
• food food

Economic Importance for Humans: Negative

Although they are abundant in the wild and documented as an enjoyably palatable fish, suckers have the public stigma of being "trash fish" or "rough fish". In the overall public view, bigmouth buffalo lack value, taste, and importance as a game fish.

Conservation Status

Bigmouth buffalo populations are healthy and secure. They are not listed as threatened in any of their native or introduced regions.

Additional Links

Encyclopedia of Life

BioKIDS Critter Catalog

Contributors

Couryn Beleck (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), Texas State University.

References

Becker, G. 1983. Fishes of Wisconsin . Madison: University of Wisconsin Press. Accessed September 24, 2013 at http://digicoll.library.wisc.edu/cgi-bin/EcoNatRes/EcoNatRes-idx?id=EcoNatRes.FishesWI .

Edwards, E. 1983. Habitat suitability index models : bigmouth buffalo . Washington, D.C.: Western Energy and Land Use Team, Division of Biological Service [sic], Research and Development, Fish and Wildlife Service, U.S. Dept. of the Interior.

Fuller, P. 2012. "USGS" (On-line). Ictiobus cyprinellus . Accessed December 15, 2013 at http://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=362 .

Kleinholz, C. 2000. Species Profile Bigmouth Buffalo. Southern Regional Aquaculture Center , 723: 1-4. Accessed October 21, 2013 at https://srac.tamu.edu/index.cfm/event/getFactSheet/whichfactsheet/145/ .

McClane, A. 1978. McClane's Field Guide to Freshwater Fishes of North America . New York: Holt, Rinehart and Winston.

Walburg, C., W. Nelson. 1966. Carp, river carpsucker, smallmouth buffalo, and bigmouth buffalo in Lewis and Clark Lake, Missouri River . Washington: Bureau of Sport Fisheries and Wildlife.

2009. "Bigmouth Buffalo Fishing in Arizona" (On-line). Arizona Game and Fish Department. Accessed November 27, 2013 at http://www.azgfd.gov/h_f/fish_bigmouth_buffalo.shtml .