Evidence of population resistance to extreme low flows in a fluvial-dependent fish species

Canadian Journal of Fisheries and Aquatic Sciences
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Abstract

Extreme low streamflows are natural disturbances to aquatic populations. Species in naturally intermittent streams display adaptations that enhance persistence during extreme events; however, the fate of populations in perennial streams during unprecedented low-flow periods is not well-understood. Biota requiring swift-flowing habitats may be especially vulnerable to flow reductions. We estimated the abundance and local survival of a native fluvial-dependent fish species (Etheostoma inscriptum) across 5 years encompassing historic low flows in a sixth-order southeastern USA perennial river. Based on capturemark-recapture data, the study shoal may have acted as a refuge during severe drought, with increased young-of-the-year (YOY) recruitment and occasionally high adult immigration. Contrary to expectations, summer and autumn survival rates (30 days) were not strongly depressed during low-flow periods, despite 25%-80% reductions in monthly discharge. Instead, YOY survival increased with lower minimum discharge and in response to small rain events that increased low-flow variability. Age-1+ fish showed the opposite pattern, with survival decreasing in response to increasing low-flow variability. Results from this population dynamics study of a small fish in a perennial river suggest that fluvial-dependent species can be resistant to extreme flow reductions through enhanced YOY recruitment and high survival

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Evidence of population resistance to extreme low flows in a fluvial-dependent fish species
Series title Canadian Journal of Fisheries and Aquatic Sciences
DOI 10.1139/cjfas-2015-0173
Volume 11
Issue 29
Year Published 2015
Language English
Publisher NRC Research Press
Contributing office(s) Patuxent Wildlife Research Center
Description 12 p.
First page 1776
Last page 1787
Country United States
Online Only (Y/N) N
Additional Online Files (Y/N) N