Accession Number : ADA138162

Title :   Effects of Ship-Induced Waves in an Ice Environment on the St. Marys River Ecosystem,


Personal Author(s) : Poe,T P ; Edsall,T A ; Hiltunen,J K

PDF Url : ADA138162

Report Date : Jan 1980

Pagination or Media Count : 33

Abstract : The Great Lakes Fishery Laboratory agreed to provide a base of information for evaluating the effects on fish, fish-food organisms, and fish habitat at those sites of ship-induced, under-ice surge waves, created by vessel passage in the adjacent ice-covered navigation channel. Macroinvertebrates of 56 taxa were identified in 75 Ponar grab samples taken during January-April at Frechette Point and Six Mile Point. Chronomidae (midge larvae), Oligochaeta (worms), and Gastropoda (snails) comprised about 67% of the total number of organisms collected. Pelecypoda (fingernail clams), Amphipoda (scuds), Polychaeta, Ephemeroptera (mayfiles), and Trichoptera (caddisflies) were common in all samples and collectively made up about 22% of the total. The density of benthic macroinvertebrates (all taxa combined) for all stations and months was 14,125.8/m2. One-way analysis of variance tests (ANOVA) revealed no significant difference (alpha = 0.05) in mean density of benthic macroinvertebrates among samples collected at different locations, water depths, and months, but subsequent evaluation of the power of these tests showed that would have failed to detect a significant difference in mean macroinvertebrate densities between locations 45% of the time, between depths 60% of the time, and between months 70% of the time. An unequivocal demonstration of effect (or no effect) would have required analysis of additional samples to improve the power of the ANOVAs, and probably also the collection of additional unaffected baseline data during a winter or series of winters when there was no vessel traffic in the study area. (Author)

Descriptors :   *Environmental management, *Natural resources, *Ecosystems, Water waves, Ships, Water traffic, Surges, Underice, Physiological effects, Fishes, Aquatic animals, Oligochaeta, Polychaeta, Gastropoda, Invertebrates, Microorganisms, Snails, Worms

Subject Categories : Administration and Management
      Economics and Cost Analysis

Distribution Statement : APPROVED FOR PUBLIC RELEASE