Abiotic drivers of spawning and early life stage assemblage dynamics of Great Plains fishes
Hydrologic regimes shape fish life histories, yet early‑life responses remain understudied in Great Plains rivers. Using multivariate models, this study examined how discharge, temperature and season influence early‑life fish assemblages in the Kansas and Marais des Cygnes rivers. Large‑bodied species such as common carp and longnose gar peaked in late spring, while small‑bodied species like red shiner and western mosquitofish remained abundant through summer. Length‑at‑age models revealed predictable hatch timing: small‑bodied species hatched continuously, whereas large‑bodied species hatched intermittently during flow pulses. These findings underscore the need for environmental‑flow strategies that reflect species‑specific responses to variable hydrology.
Subject Tags
- Rivers
- Wildlife
- Fisheries
Abstract
The hydrologic regime is a primary driver of environmental conditions in rivers and plays a key role in structuring fish assemblages. Fish have adapted life history strategies in response to natural flow and temperature regimes that provide spawning cues and influence recruitment success. However, the extent to which abiotic factors shape early life stage assemblage structure, particularly hatching and recruitment, remains understudied in Great Plains rivers where fish are adapted to stochastic hydrologic regimes. We used multivariate models to assess the influence of discharge, temperature, and month on early life stage fish assemblage structure in the Kansas and Marais des Cygnes rivers. We also developed length-at-age models to estimate hatch dates and evaluate how hatch timing aligns with environmental conditions. Early life stage assemblages exhibited chronological patterns in abundance, with large-bodied species such as common carp Cyprinus carpio and longnose gar Lepisosteus osseus peaking in late spring, while small-bodied species such as red shiner Cyprinella lutrensis and western mosquitofish Gambusia affinis remained abundant throughout the summer. Hatch frequency exhibited predictable patterns based on life history strategy, with small-bodied species hatching continuously over extended periods, while large-bodied species hatched intermittently, often coinciding with flow pulses. These findings highlight the need for a nuanced approach to environmental flow management that accounts for species-specific responses to variable hydrologic conditions.
Citation
Krellwitz, E. M., Gido, K. B., Mehl, H. E., Totten, L. A., & Jones, T. C. (2026). Abiotic drivers of spawning and early life stage assemblage dynamics of Great Plains fishes. River Research and Applications, 42(1), 3-18. https://doi.org/10.1002/rra.70046
TNC Authors
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Heidi E. Mehl
Great Plains Division Director of Freshwater
The Nature Conservancy
Email: heidi.mehl@tnc.org