About Macrhybopsis storeriana (Kirtland, 1845)
Macrhybopsis storeriana, commonly known as the silver chub, reaches a maximum total length of 231 mm (9.1 in). Its dorsal side is pale grey-green, fading to silvery on the sides and silvery white on the belly. The iris is white-yellow, and a faint dark dusky lateral stripe is usually present. The caudal fin is lightly pigmented, except for the lower 3–4 rays which are completely unpigmented. Silver chubs have a slender, moderately compressed body that is flattened on the ventral side. Their mouth is inferior and horizontal, they possess a maxillary barbel, the premaxilla is protractile, and the upper lip is separated from the skin of the snout by a deep continuous groove that runs along the midline. The lateral line is either straight or forms a broad arch. Adult males have large, uniserial tubercles on the dorsal surface of pectoral fin rays 2–10; minute sensory buds are present on the head, but breeding tubercles do not occur there. Silver chubs are mainly restricted to large, often silty rivers, and are sometimes found near the mouths of small streams. In the United States, the species is widespread from southern New York west to the Red River drainages. In Texas, it occurs in the Red River and the lower Brazos River; the Brazos River population is apparently geographically isolated from other populations of the species, which range through the Mississippi River basin to Mobile Bay. Recorded spawning seasons vary by location: it is late spring to early summer in Iowa, June and July in Wisconsin. In western Lake Erie, spawning begins the second week of June at 19 °C (66 °F), peaks during the last week of June and first week of July at 23 °C (73 °F), and finishes by mid-August. Research by Kinney in 1954 concluded this species spawns at relatively high temperatures. Silver chubs spawn over rock and gravel, and produce pelagic free embryos. Males live up to three years, while females live up to four years. Kinney (1954) found most one-year-old silver chubs are sexually mature. On average, the species reaches 124 mm (4.9 in) in standard length after the first year of growth, 147 mm (5.8 in) after the second year, and 164 mm (6.5 in) after the third year.
