Population dynamics and aging structure comparison reveals newfound longevity of blue suckers (Cycleptus elongatus) in a Missouri River tributary

Abstract

Blue suckers [ Cycleptus elongatus (Lesueur, 1817)] are declining in much of their native range, and recent research suggests they may be longer lived than previously estimated. We compared pectoral fin ray and lapillus otolith age estimates and estimated population dynamics parameters from otolith-based ages for a stable blue sucker population near the James River-Missouri River confluence from 2020 to 2022. Length–weight regressions were similar between sexes. Pectoral fin rays were found to underestimate ages by as much as 40 years compared to otoliths beginning at age 12 years, and the oldest estimated otolith age was 61 years. Year-class strength increased with median spring discharge, and strong year classes occurred at flows > 48 m 3 /s). Females appeared to grow larger than males, and sex-specific natural mortality estimates were ≤ 10%. This study provides needed demographic data derived from otolith estimates on a stable population of blue suckers.

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