| Movement patterns and habitat associations of native bluehead sucker Catostomus discobolus and flannelmouth sucker Catostomus latipinnis as well as introduced white sucker Catostomus commersonii and longnose sucker Catostomus catostomus in the Big Sandy River, Wyoming were studied. This study indicated that both native and introduced catostomids widely overlapped in their use of the Big Sandy River. Fall and winter movements of all four species of catostomids were within 2 km of the previous location, and all four species selected pools with rock substrates during these seasons. Spring movements and habitat use varied among species with bluehead suckers and flannelmouth suckers moving downstream, white suckers remaining sedentary, and longnose suckers moving upstream. Bluehead suckers selected pools with rock substrates, flannelmouth suckers selected braided channels with sand substrates, white suckers selected pools, and longnose suckers selected deep runs during spring. Age, growth and length structure of bluehead suckers, flannelmouth suckers, and white suckers in the Big Sandy River and Little Sandy Creek, Wyoming were also studied. Flannelmouth suckers had the fastest growth and the maximum estimated age in both the Big Sandy River and Little Sandy Creek; whereas bluehead suckers had the slowest growth in both systems and the shortest maximum estimated age in Little Sandy Creek, but an intermediate maximum estimated age in the Big Sandy River. Length-frequency distributions of bluehead suckers, flannelmouth suckers, and white suckers could not accurately predict population age structure, and suggested a lack of recent recruitment in the Big Sandy River but not in Little Sandy Creek. |
