Cycleptus

Abstract: – Blue suckers, Cycleptus elongatus, are a highly mobile species speculated to have spring spawning migrations. However, previous studies have not quantified seasonal migrations of blue suckers. Use distributions were calculated at 90% and 50% for three seasons to identify geographic space-use requirements of blue suckers. Mean 90% use distributions (±SE) varied from 8.1 km (±5.3 km) in summer to 78.6 km (±9.9 km) in fall to 174.9 km (±13.1 km) in spring. The great space-use requirements of blue suckers in fall and spring indicate that the species makes substantial upstream migrations in fall and also preceding spawning in spring, then return to a core area postspawning. The broad geographical range occupied by blue suckers throughout their life-history cycle emphasises the need for interjurisdictional management of the species and highlights potential detrimental effects of blocking fish passage.

Abstract: Population density of five species of chubs and two species of minnows in the Missouri River in Nebraska has been reduced by as much as 95% since 1971. Burbot have been nearly extirpated, sauger have been greatly reduced, and blue catfish are rare. Reasons for the decline ofthese species include removal ofsnags from the river; cessation of organic matter and sediment transport because of the construction of large dams on the mainstem and tributaries; cutoff of floodplain connection through channelization, degradation, and the cessation of flooding; alteration of the natural hydrograph to meet the need for commercial navigation; and reduction of the natural water temperature regime because of deep release of cold water from the large reservoirs. We propose remedial actions for each of these ecological changes, and we propose listing of several species as endangered in Nebraska. In 1838, federal engineers initiated the most significant restructuring of the Missouri River since the last Pleistocene glacier retreated northward. Snags were removed, dams were constructed on the mainstem and tributaries, channels were armored with rock and piling, the natural hydrograph was replaced with a monthly metered flow, sediment and organic matter transport was short-stopped, and the floodplain was made safe for human development. At the time of construction, nothing was done to mitigate damage to the ecosystem. The impact set inmotion by these changes will neverbe thoroughly quantified, and a semblance ofphysical and biological equilibria will not happen again for decades, if ever (petts 1984). We do know that the Missouri BRS 17 / Hesse et al. / Preliminary draft 7-30-93/ P1 9-7-93/ camera copy 114-93/ cc1l124-93 328 BIOLOGICAL REroRT 19 River was shortened by at least 204 km and more than 178 million ha of river channel, erosion zone, floodplain grass and timber, and tributary valley lands were either inundated or converted to crop land (Hesse 1987; Hesse and Schmulbach 1991). At least 160 species of wildlife were resident or migrant visitors to this ecosystem, and 156 native fish species lived in the mainstem and tributaries (Hesse et al. 1988; Hesse et al. 1989). Nebraska's imperiled Missouri River wildlife include the interior least tern (Sterna antillarum), piping plover (Charadrius melodus), peregrine falcon (Falco peregrinus), and bald eagle (Hatiaeetus leucocephalus), all protected by the Endangered Species Act (ESA). The pallid sturgeon (Scaphirhynchus albus) was most recently (1990) listed as endangered (Federal Register 55 (173):36641). Other species have been federally listed as Category 2 (taxa for which present information indicates the possible need to list, but more information is required before listing can proceed), including: blue sucker (Cycleptus elongatus), sturgeon chub (Macrhybopsis gelida), sicklefin chub (Macrhybopsis meeki), and lake sturgeon (Acipenser fluvescens). Paddleflsh (Polyodon spathula) is a Category 2 species and was recently proposed for listing in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES; Federal Register 56 (142):33894). This paper discusses (1) differences in density of selected flsh species over time and between reaches of the Missouri River, based on changing harvest by sport and commercial flshermen and on catch per unit effort (CPUE) from biological surveys, and (2) remedial actions that will preserve and restore original features and functions of the Missouri River as an ecosystem. Sources of Data and Methods The Nebraska Game and Parks Commission has supported research on Missouri River fisheries since the late 1950's. Historical databases exist from seining, explosives, creel surveys, commercial flshing reports, electrofishing, gill netting, and plankton drift netting. Many other methods were used to collect in unique situations. These methods are discussed in Mest! andHesse (1991). Seine samples are reported as the number of fish per seine haul. One standard seine haul constituted a perpendicular extension of a 15.24x l.83-mbagseine, followed by an extended drag to shore while maintaining one end of the net stationary. However, standardizing a seine haul was very difficult because ofvarying depth and the condition of the substrate. Mesh size was always 6.13 mm. All seined fish were preserved and identified in the laboratory. Cyprinids and catfish were collected from tributary streams with an explosive (primacord). A unit of effort consisted of a 15.2-m length of explosive, containing 162.5 grains of PETN/m. Bankline and sandbar habitats were sampled. A block netwas used to capture fish killed by the blast. Angler surveys have been conducted periodically in the tallwater of Gavins Point Dam and at selected locations downriver since 1956. The most recent survey was a recreational use survey conducted during 1992. Commercial fishers were first required to purchase a license and report their catch beginning in 1944 (Nebraska) and 1945 (Missouri). Although reports were required, they were completed annually, and by fishers themselves, with little opportunity for verification. However, we believe these reports are useful to show trends in abundance of selected species based on harvest trends. Boat-mounted electrofishing (AC and DC) has been used since the early 1960's to collect a wide range of species. We have observed different catch rates associated with the widely varying water quality conditions throughout the river. For this reason only catch per unit effort (CPUE) that differed widely is reported. Small differences cannot be justifIably assigned to changing conditions of habitat and water management. Collections were based on time spent sampling, and CPUE was the number offish per unit oftime spent electrofishing. Experimental gillnet collections were usually limited to the unchannelized Missouri River between Fort Randall Dam and Lewis and Clark Lake (Gavins Point Dam; Figure). This is the only reach in Nebraska with extensive off-channel and sandbarpool habitat remaining. The nets were either91 m or 61 m long, and 2.44 m deep, with six equal length panels of netting ranging from 12.7-mm to 76.2-mmmesh sizes. Nets were anchored late inthe afternoon and retrieved early the next day. Data were recorded by net length, and CPUE was the number of fish caught per net-night. Larval fish were filtered from the main channel at cutting and filling banks and at mid-channel with paired, 1-m-diameter plankton nets (560 microns). Flow meters in the net mouths were used to quantify volume of water filtered, and duration per tow was minimal to prevent net clogging. The BRS 17/ Hesse et al. / Preliminary draft 7-3(}93 / P1 9-7-93/ camera copy 11-4-93/ ccIl12-4-93 LARRY W. HEsSE ET AI.. 329 Scale: 1 centimeter 18.1 kilometers' Kansas Figure. Map ofthe Missouri River showing the lowennost dams and unchannelized and channelized segments. Iowa Big Sioux

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.

Abstract: The total length (L, mm)-weight (W, g) relationship for 153 blue suckers (Cycleptus elongatus) collected from areas of swift current in Pool 20, Mississippi River, was log10W = −6.69 + 3.59(log10L). Condition factors (K = 105W/L) were 0.74−1.1; they increased with increasing fish size, and varied among months (March-October) and between years (1977–1978). Fin rays had more discernible annuli than scales after age VII. The largest blue sucker collected was age X (scales) or XIII (fin rays) and 817 mm long. Males generally reached sexual maturity at age IV, females at age VI. Males had nuptial tubercles during April, but no ripe females were found. For six females aged VI-IX (617–736 mm), the fecundity (Y, number of 1-mm diameter eggs)-length relationship was Y = −375,100 + 771.5L. Blue suckers ate primarily Tricoptera and Diptera larvae and pupae, and lesser numbers of Ephemeroptera larvae and amphipods.