Effects of temperature gradients resulting from reservoir discharge on Dorosoma cepedianum spawning in the Savannah River

Michael H. Paller, Bruce M. Saul

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

The timing and spatial pattern of gizzard shad, Dorosoma cepedianum, spawning were markedly affected by a temperature gradient caused by the release of hypolimnetic water from an upstream reservoir into the middle reaches of the Savannah River. During 1983 and 1984, a distinct thermal gradient occurred with the warmest temperatures at the downstream end of the 257 km study reach and the coolest temperatures at the upstream end. The occurrence of gizzard shad larvae indicated that spawning began at the sample stations farthest downstream and progressed upstream, peaking at each sample station when it warmed to approximately 19°C. The estimated difference in date of peak density of larvae between the upstream and downstream ends of the gradient was 23 days in 1983 and 35 days in 1984. Because of this pattern, densities of larvae were highest at the downstream end of the study area early in the spawning season and highest at the upstream end of the study area late in the spawning season. Photoperiod and daylength appeared unrelated to the patterns under study. Far-reaching effects of anthropogenic temperature changes on fish spawning and the distribution of larvae are probably common in rivers that receive hypolimnetic discharge.

Original languageEnglish (US)
Pages (from-to)151-160
Number of pages10
JournalEnvironmental Biology of Fishes
Volume45
Issue number2
DOIs
StatePublished - Feb 1996

Keywords

  • Dam
  • Distribution
  • Fish larvae
  • Gizzard shad
  • Hypolimnetic discharge

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science

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