Larval and early juvenile fish dynamics in main channel and backwater lake habitats of the Illinois River ecosystem

Michael A. Nannini, Jodi Goodrich, John M. Dettmers, Daniel A. Soluk, David H. Wahl

Research output: Contribution to journalArticlepeer-review


The spatial and temporal complexity of large river ecosystems likely promotes biological diversity within riverine larval fish assemblages. However, the focus of most previous riverine studies of larval fish distribution has tended to concentrate mainly on backwater habitats. There has been less focus on the value of the main channel for larval fishes. We sampled two habitats types (three main channel sites and three backwater lakes) along 20 km of the Illinois River ecosystem during 2 years to compare the larval fish distribution along both spatial and environmental gradients between these habitats. Across the 2 years of this study, we found similar trends in the spatial and temporal distribution of larval fish, although there were some differences in densities between years. The relative abundance and size of many of the different fish taxa varied among habitats. Centrarchids, clupeids, poeciliids, cyprinids (excluding common carp) and atherinids were more abundant within backwater lake habitat. In contrast, common carp (Cyprinus carpio), sciaenids, moronids and catostomids were more abundant in main channel habitats. Furthermore, sciaenid and clupeid larvae captured in the backwater lake habitat were larger as the season progressed than those captured in the main channel. Our study suggests that larval fish show habitat specialisation, similar to adults, indicating that both the backwater lakes and the main channel are both important for larval fish and preserving the diversity of the fish assemblages in large floodplain rivers.

Original languageEnglish (US)
Pages (from-to)499-509
Number of pages11
JournalEcology of Freshwater Fish
Issue number4
StatePublished - Oct 2012


  • Backwater habitat
  • Large floodplain river
  • Larval fish
  • Main channel habitat

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science
  • Ecology


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