Seasonal use distributions and migrations of blue sucker in the Middle Missouri River

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.