Observations on the Natural History of the Blue Sucker (Cycleptus elongatus Le Sueur) in the Neosho River

Abstract

Populations of blue suckers in the Neosho River in Kansas were sampled by electrofishing during the spring and summer of 1976 and 1977. Spawning occurred in deep riffles (1-2 m) with cobble and bedrock substrates in May at water temperatures of 20-23 C. By August, juveniles averaged 125 mm in length. Mature females reach greater maximum ages, weights and lengths (9 years, 4.1 kg, 763 mm T.L.) than males (7 years, 3.7 kg, 749 mm T.L.). In general, adult females were larger than adult males. Condition coefficients vary slightly with time of year. Only a few juveniles were captured, but young blue suckers occupied shallower and less swift water than adults. Laboratory stream observations confirm a preference for smooth substrates in swift current. Food of adults and young consisted primarily of insect larvae and plant material. Blue suckers seem limited by habitat, especially during spawning. INTRODUCTION The blue sucker, Cycleptus elongatus Le Sueur, is distributed from Montana to Wisconsin and Pennsylvania S to Kentucky, the Gulf of Mexico, Texas and northern Mexico (Alvarez, 1970; Brown, 1971; Clay, 1975; Douglas, 1974; Eddy, 1969; Hubbs, 1957; Smith-Vaniz, 1968). It is found in deep reservoirs (Carlander, 1969; Jenkins, 1953), but its principal habitat is the Mississippi and Missouri rivers and their largest tributaries (Pflieger, 1971, 1975). It also occurs in the Pearl and Rio Grande rivers and tributaries (Contreras and Rivera, 1972). The blue sucker is considered to be one of the finest of the freshwater food fishes and perhaps the best of the suckers (Coker, 1930; Forbes and Richardson, 1920). It was once an important part of the commercial catch of the Mississippi drainage. In 1899, the Mississippi catch was nearly 1 million kg (Coker, 1930). Today it is scarce in commercial catches. Despite its former abundance commercially, little natural history information about blue suckers has been available (Cross, 1967; Harlan and Speaker, 1956; Miller and Robison, 1973; Pflieger, 1975; Trautman, 1957) and information on age and growth was based on relatively few specimens (Carlander, 1969). Recently, Gilbert (1980) presented North American distributional information and Rupprecht and Jahn (1980) discussed size, growth, reproduction and food habits for Mississippi River blue suckers. We were able to accumulate information on habitat and spawning and complementary data on ages and growth and food habits for blue suckers in the Neosho River. METHODS The Neosho River, a tributary to the Arkansas River, drains southeastern Kansas, southwestern Missouri and northeastern Oklahoma. Our collections were from the Neosho mainstream in Labette Co. (juveniles), Lyon Co. (juveniles) and Woodson Co. (adults, spawning riffle) in Kansas. Fish were collected from early April through October in 1976 and 1977 by electrofishing with either a boom-type boat or backpack electrofisher (both D. C.). Blue suckers are very vulnerable to electrofishing, often remaining stunned for minutes after being shocked. Generally, the most effective method was to let the boat drift through deep riffles (1-2m) and return quickly upstream to net stunned fish. In shallow riffles, especially over bedrock, the backpack electrofisher was used with set seines to capture juveniles. l Present address: CSA, Natural Sciences, University of Michigan, Ann Arbor 48109.