| Abstract: | Ichthyoplankton samples were collected twice monthly during spring and summer 1981 from a variety of habitats in Navigation Pool 7 of the upper Mississippi River. Larval-fish distributions in the pool and variations in those distributions were analyzed relative to potential impacts of increased commercial navigation. Although as many as 66 species of adults have been found in the area (33 considered common), only 17 taxa were identified from our collections. In April and May, most larvae were collected in main-channel and main-channel-border areas next to major expanses of shallow backwaters. White bass Morone chrysops, yellow perch Perca flavescens, and crappies Pomoxis spp. were predominant. Numerous catostomids also were taken. In June and July, most larvae were taken in the lower pool. Freshwater drum Aplodinotus grunniens and gizzard shad Dorosoma cepedianum predominated in these samples, which also included many cyprinids and centrarchids. Diel patterns of abundance varied with species and sampling location. Freshwater drums were more abundant near the surface at midnight than during the day. Common carp Cyprinus carpio were most abundant in collections at dusk, whereas all other cyprinids were most abundant at dusk and dawn. Numbers of gizzard shad also increased slightly at dusk. Total numbers of larvae collected were greatest at dusk in main-channel and main-channel-border samples; backwater areas produced the greatest catches at midnight and dawn. Seasonal, spatial, diel, and species-specific variations in larval fish abundances significantly influenced the proportion of the community potentially vulnerable to increased boat traffic through Pool 7. |
| Genre: | Article |
| ProdID: | 1003096 |
| Citation Author: | Holland, L. E. ; Sylvester, J. R. |
| Citation Contributing Office: | Upper Midwest Environmental Sciences Center |
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| Citation End Page: | 301 |
| Citation Issue: | 2b |
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| Citation Language: | English |
| Citation Larger Work Title: | Transactions of the American Fisheries Society |
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| Citation Number Of Pages: | 9 |
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| Citation Phsyical Description: | pp. 293-301 |
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| Citation Search Results Text: | Distribution of larval fishes related to potential navigation impacts on the upper Mississippi River, pool 7; 1983; Article; Journal; Transactions of the American Fisheries Society; Holland, L. E. ; Sylvester, J. R. |
| Citation Start Page: | 293 |
| Citation Volume: | 112 |
| Citation Year: | 1983 |
| Type: | citation/reference |
| Text: | Distribution of larval fishes related to potential navigation impacts on the upper Mississippi River, pool 7; 1983; Article; Journal; Transactions of the American Fisheries Society; Holland, L. E. ; Sylvester, J. R. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (INDEX PAGE): | http://afsjournals.org/doi/abs/10.1577/1548-8659%281983%29112%3C293%3ADOLFRT%3E2.0.CO%3B2 |
| Date Other: | Sat, 1 Jan 1983 00:00 -0600 |
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