Macrhybopsis hyostoma

shoal chub

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Type Locality

East Fork of White River, at Bedford, Lawrence County, Indiana (Gilbert 1884).

Etymology/Derivation of Scientific Name

Macr – Greek, meaning “long”, referring to elongated forms of Hybopsis ; hyostoma – hyo = hog, and stoma = mouth (Scharpf 2005). Shoal chub, the common name, refers to the typical habitat of coarse sand and gravel raceways with strong current (Eisenhour 2004).

Synonymy

Macrhybopsis hyostoma recognized as distinct species in the M. aestivalis complex by Eisenhour (1999). See Eisenhour (1997) for complete synonymy.

Nocomis hyostomus Gilbert 1884:203.

Hybopsis hyostomus Jordan and Evermann (1896).

Extrarius aestivalis (Starrett 1950, 1951).

Extrarius aestivalis hyostomus (by C. L. Hubbs; see Eisenhour 2004).

Hybopsis aestivalis hyostomus Davis and Miller (1967); Becker (1983).

Hybopsis aestivalis hyostoma Cross (1967); Trautman (1981).

Hybopsis aestivalis Klutho (1983).

Macrhybopsis aestivalis hyostomus

Macrhybopsis hyostoma Eisenhour (2004); Hubbs et al. 2008:21.

Characters Considerable geographic variation present in Macrhybopsis hyostoma; see Eisenhour (2004) for additional information.

Maximum size: 76 mm TL (female); 66 mm TL (male; Eisenhour 1997, 2004).

Coloration: Straw color dorsally, white ventrally.  Small to large pigments on dorsal.  Pigmentation on fins variable, usually along rays of pectoral, pelvic, dorsal, anal and caudal fins.

Eisenhour (2004) described life colors: translucent pale green or gray dorsally, silvery white ventrally, with broad silver lateral stripe. Concentrations of small melanophores on margins or submargins of dorsolateral scales form weakly (turbid streams) to strongly expressed (clear streams) pigment pattern. On caudal peduncle, the lateral stripe is well to poorly defined, but fades anteriorly, centered on lateral line to one scale row above lateral line. Pectoral fin usually well-pigmented along rays; anal, pelvic, and dorsal fins with only scattered melanophores along rays or unpigmented.

Eisenhour (2004) noted that specimens from the middle Red River are pallid overall, with poorly defined or absent lateral stripes and submarginal dorsolateral scale pigmentation. Of all M. hyostoma populations examined, the lateral stripe and submarginal dorsolateral scale pigmentation was most reduced in Brazos River and Colorado River populations, and Brazos River specimens were more pallid than those from the clearer Colorado River.

Counts: Pharyngeal teeth 0,4-4,0; 19 (15-21) principal caudal scales; 8 (7-10) anal rays; 7-8 (6-9) pelvic rays; 13-16 (11-18) pectoral rays; 35-38 (32-43) lateral line scales; 12-16 (2-21 predorsal scales; 5-6 (4-7) scales above lateral line; 4-5 (3-6) scales below lateral line; 12 (11-16) caudal peduncle scales; 12-16 (10-20) infraorbital pores; 10-13 (9-15) preoperculomandibular pores; 35-37 (34-39) total vertebrae; 17-18 (16-19) precaudal vertebrae; 18-20 (17-22) caudal vertebrae (Eisenhour 2004). Gill rakers on first arch usually absent, occasionally 1-2 dorsal rudiments are present (Eisenhour 2004).

Populations from the Colorado and Brazos rivers (TX) have fewer lateral-line scales and vertebrae than populations in the remainder of the M. hyostoma range. Specimens from the middle Red River have high mean scale counts and few mean infraorbital pores (Eisenhour 2004).

Body shape: Dorsally humped and ventrally flattened; rounded snout. Body fusiform with moderately thick caudal peduncle; snout moderately rounded and moderately flattened ventrally; mouth not as wide as head when viewed ventrally; lips moderately fleshy and not thickened posteriorly; eyes small and suboval to large and oval (Eisenhour 2004).

Populations in the middle Red River and the Brazos River have smaller eyes than other M. hyostoma populations; specimens from the Brazos River have smaller eyes than specimens from the Colorado River (Eisenhour 2004).

Mouth position:  Horizontal and subterminal (almost inferior)

External morphology: Eyes set high on head, cross-eyed appearance when viewed from above. One or two pairs of maxillary barbels present; anterior barbels < 50% of orbit length or absent, posterior barbel length usually < orbit length; nape fully scaled (in about 95% of specimens examined) or with scattered embedded scales; belly squamation variable; anal and dorsal fins bluntly pointed to slightly falcate; pelvic fins rounded to pointed; pectoral fins variable in shape and short, not reaching bases of pelvic fins in adult males; large taste buds expanded into papillae on gular area; genital papillae poorly developed as small conical or cylindrical extensions in both sexes (Eisenhour 2004). Pectoral rays 2-10 thickened in large nuptial males and bear rows of conical, antrorse uniserial tubercles; tiny tubercles rarely present on rays of dorsal and pelvic fins in large (>50 mm SL) nuptial males in peak condition (Eisenhour 2004).

Populations from the Brazos River and Colorado River (TX) always lack a second pair of barbels (Eisenhour 2004); specimens from the Brazos River had longer barbels and lower mean belly squamation indices than specimens from the Colorado River.

Distribution (Native and Introduced)

U.S. distribution: Widely distributed in the Mississippi River basin and the West Gulf Slope west to the Lavaca River drainage, Texas (Eisenhour 2004).

Texas distribution: Sabine River to the Lavaca River (Eisenhour 2004; Hubbs et al. 2008); Sabine, Brazos and Colorado rivers (Underwood et al. 2003).

Abundance/Conservation status (Federal, State, NGO)

Common in some areas whereas extirpated in many river systems throughout their range (Luttrell et al. 2002, Eisenhour 2004). Currently stable in the lower Brazos River (Runyan and Bonner, TWDB Report). Endangered status in Ohio (Scharpf 2005), Threatened status in Wisconsin (Becker 1983; Scharpf 2005). Extirpated from the Cumberland River (Etnier and Starnes 1993), the upper Kansas River drainage (Eisenhour 2004), the Arkansas River mainstem in Arkansas (Luttrell et al. 1999) and the Osage River, Missouri (Eisenhour 2004). Abundance and distribution of this species has declined in the Mississippi mainstem above the mouth of the Missouri and in the Nebraska portion of the Missouri River (Eisenhour 1997, 2004).

Habitat Associations

Macrohabitat:  Medium to large rivers (Becker 1983; Eisenhour 1997, 2004; Winemiller et al. 2004). Eisenhour (1997) noted that M. hyostoma was noticeably absent in stream reaches affected by reservoirs and locks and dams or heavily modified by channelization.

Mesohabitat:  Eisenhour (1997) reported collection of most individuals from deeper water (1.0-1.8 m) in strong currents over coarse sand and pea gravel; some specimens collected over fine sand or coarse gravel and cobbles; densest concentrations of individuals occurred in streams with well defined pools and riffles/runs, braided channels, and shifting sand/gravel bars. Considered a habitat specialist; both juveniles and adults preferred run habitats with clean sand or pea-size gravel substrates and moderate current velocities (20-40 cm/s; Luttrell et al. 2002). In the Mississippi River (Illinois), species was significantly associated with high water levels, a sand substrate, moderate (21-30 cm/s) current velocity, and was collected at night (65% of the time) during 24-hour sampling; species dominated the assemblage during April and May, was second most abundant in March, and was collected during every month except January (Klutho 1983); common in shallow water at night (Trautman 1981; Klutho 1983). In the Big Blue and Little Blue rivers (Kansas), species was restricted to wide, swift parts, and occurred over clean, sometimes shifting, sand bottoms (Minckley 1959). In Wisconsin, found most frequently in broad, shallow riffles over substrates of sand (62% frequency), mud (23%), clay (8%), and gravel (8%); vegetation was generally lacking and water was slightly turbid to turbid at collection sites. In the Brazos River (Texas), density of fish was consistent through the year and rather weakly associated with peak discharge (Winemiller et al. 2004).

Biology

Spawning season: Minckley (1959) reported collection of breeding males, from the Big Blue River Basin (Kansas), in late May; and collection of males and females with well-developed gonads in mid-June at water temperature of 25°C. In Wisconsin, females with mature eggs were collected in August (Becker 1983). Brazos River population assessed by C. S. Williams. 

Spawning habitat:  Open water

Spawning behavior:  Likely similar to Macrhybopsis tetranema (peppered chub), which is a flood-pulse spawner (Bottrell et al. 1964; Miller and Robison 2004): 

Fecundity: Becker (1983) reported collection of a female (61 mm TL, 1.71 g) with ovaries 12.2% of the total weight containing 796 mature yellow eggs 0.9 (0.7-1.0) mm diameter, and white, immature eggs 0.2 (0.1-0.3) mm diameter; and a female (55 mm TL, 1.38 g) with ovaries 9.4% of the body weight containing 559 eggs, about half of which were mature and measured 0.7 (0.65-0.8) mm diameter; other females collected (thought to have recently spawned) still contained a number of mature eggs 0.8 mm diameter. Brazos River population assessed by C. S. Williams. 

Age at maturation: 1 year (Starrett 1951).

Migration

Growth and Population Structure: Information available (C. W. Williams) pending review. In the Brazos River (Texas), the population consisted of at least three age groups (age 0, 1, and 2): Age-0 fish (year class 2004) were collected May – August 2004; age-1 fish (year class 2003) and age-2 fish were collected November 2003 – July 2004 (Winemiller et al. 2004). One-hundred and ninety-five age-1 individuals were collected from the Wisconsin River (Wisconsin): 109 males were 47.3 (43-54) mm TL; 86 females were 52.2 (45-61.5) mm TL (Becker 1983). In the Des Moines River (Iowa), age-I fish measured 18-53 mm SL, in May; 24-49 mm SL, in July; and 34-51 mm SL, in October (Starett 1951).

Longevity: 1-2 years (Starrett 1951).

Food habits: In the Des Moines River (Iowa) fish fed on aquatic insects, small crustaceans, and plant material; Starrett (1950) classified species as a Diptera feeder. Identifiable food items from the digestive tracts of 22 specimens collected from the Wisconsin River (Wisconsin) in August were: Trichoptera, Hemiptera, Odonata, Coleoptera, cycloid fish scales, and debris; 10 of the 22 digestive tracts were empty (Becker 1983) Primarily sight-feeders (Davis and Miller 1967). Diet of fishes from the Brazos River is available (C. S. Williams) pending review. 

Phylogeny and morphologically similar fishes

Macrhybopsis hyostoma is distinguished from all other members of the M. aestivalis complex (M. aestivalis, M. australis, M. marconis, M. tetranema) by the combination of relatively large, oval eyes, posterior barbels < orbit length, anterior barbels absent or <50% of orbit length, uniserial pectoral fin tuberculation in nuptial males, absence of prominent genital papilla and head tuberculation, a moderately well-developed lateral stripe on caudal peduncle, few or no scales with clusters of small melanophores, and posterior placement of the anus (Eisenhour 2004); M. hyostoma has a moderately rounded snout, more so than in M. australis and M. tetranema, but less than in M. aestivalis and M. marconis. Allopatric with other species in the M. aestivalis complex in Texas except in the Colorado River drainage (sympatric with M. marconis) and Red River drainage (sympatric with M. australis; Underwood et al. 2003; Eisenhour 2004).

Host Records

Commercial or Environmental Importance

Isolation of many Macrhybopsis hyostoma populations has occurred due to habitat fragmentation resulting from reservoir construction, channelization, and other anthropogenic disturbances to the hydrology of streams (Eisenhour 1997, 2004).

References

Becker, G.C. 1983. Fishes of Wisconsin. The University of Wisconsin Press, Madison, 1052 pp.

Bottrell, C.E., R.H. Ingersol, and R.W. Jones. 1964. Notes on the embryology, early development, and behavior of Hybopsis aestivalis tetranemus (Gilbert). Transactions of the Microscopial Society 83(4):391-399.

Cross, F.B. 1967. Handbook of fishes of Kansas. Univ. Kansas Misc. Publ. 45:1-357.

Davis, B.J., and R.J. Miller. 1967. Brain patterns in minnows of the genus Hybopsis in relation to feeding habits and habitat. Copeia 1967(1):1-39.

Eisenhour, D.J. 1997. Systematics, variation, and speciation of the Macrhybopsis aestivalis complex (Cypriniformes: Cyprinidae) west of the Mississippi River. Ph. D. dissertation Southern Illinois University, Carbodale. 260 pp.

Eisenhour , D.J. 1999. Systematics of Macrhybobsis tetranema (Cypriniformes: Cyprinidae). Copeia 1999: 969-980.

Eisenhour, D.J. 2004. Systematics, variation, and speciation of the Macrhybopsis aestivalis complex west of the Mississippi River. Bulletin Alabama Museum of Natural History 23:9-48.

Etnier, D.A., and W.C. Starnes. 1993. The Fishes of Tennessee. The University of Tennessee Press, Knoxville. 681 pp.

Hubbs, C., R.J. Edwards, and G.P. Garrett. 2008. An annotated checklist of the freshwater fishes of Texas, with keys to identification of species. Texas Journal of Science, Supplement, 2^nd edition 43(4):1-87.

Klutho, M.A. 1983. Seasonal, daily, and spatial variation of shoreline fishes in the Mississippi River at Grand Tower, Illinois. Unpubl. M. S. Thesis, Southern Illinois Univ., Carbondale. 83 pp.

Luttrell, G.R., A.A. Echelle, W.L. Fisher, and D.J. Eisenhour. 1999. Declining status of two species of the Macrhybobsis aestivalis complex (Teleostei: Cyprinidae) in the Arkansas River Basin and related effects of reservoirs as barriers to dispersal. Copeia 1999: 981-989

Luttrell, G.R., A.A. Echelle, and W.L. Fisher. 2002. Habitat correlates of the distribution of Macrhybopsis hyostoma (Teleostei: Cyprinidae) in western reaches of the Arkansas River Basin. Transactions of the Kansas Academy of Science 105(3-4):153-161.

Miller, R.J., and H.W. Robison. 2004. Fishes of Oklahoma. University of Oklahoma Press, Norman. 450 pp.

Minckley, W. L. 1959. Fishes of the Big Blue River Basin, Kansas. Univ. Kansas Publ., Mus. Nat. Hist. 11:401-442.

Scharpf, C. 2005. Annotated checklist of North American freshwater fishes, including subspecies and undescribed forms, Part 1: Petromyzontidae through Cyprinidae. American Currents, Special Publication 31(4):1-44.

Starrett, W.C. 1950. Food relationships of the minnows and darters of the Des Moines River, Iowa. Ecology 31(2):216-233.

Starrett, W.C. 1951. Some factors affecting the abundance of minnows in the Des Moines River, Iowa. Ecology 32(1):13-27.

Trautman, M.B. 1981. The Fishes of Ohio. Ohio State University Press, Columbus, 782 pp.

Underwood, D.M., A.A. Echelle, D.J. Eisenhour, M.D. Jones, A.F. Echelle, W.L. Fisher. 2003. Genetic variation in western members of the Macrhybopsis aestivalis complex (Teleostei: Cyprinidae), with emphasis on those of the Red and Arkansas river basins. Copeia 2003(3):493-501.

Winemiller, KO., F.P. Gelwick, T. Bonner, S. Zueg, and C.Williams. 2004. Response of oxbow lake biota to hydrologic exchanges with the Brazos River channel. Texas Agricultural Experiment Station and Texas State University to Texas Water Development Board. 59 pp.