Lethal Effects of Suspended Sediments on Estuarine Fish.
Abstract
A 3-year laboratory study identified certain estuarine fish sensitive to the effects of particle size and concentration of (a) suspended mineral solids similar in size to sediments likely to be found in estuarine systems in concentrations typically found during flooding, dredging, and disposal of dredged material, and (b) natural sediments in identical experiments. Significant mortality of estuarine fish was demonstrated at these suspended mineral solid concentrations. Estuarine fish were classified, using static bioassays as: Tolerant (24-hour LC10 greater than or equal to 10 grams per liter), sensitive (10 grams per liter greater than 24-hour LC 10 greater than 1.0 gram per liter), or highly sensitive (24-hour LC10 greater than or equal to 1.0 gram per liter) to fuller's earth suspensions. Generally, bottom-dwelling fish species were most tolerant to suspended solids; filter feeders were most sensitive. Early life stages were more sensitive to suspended solids than adults; filter feeders were most sensitive. Bioassays with natural sediments indicated that suspensions of natural muds affected fish in the same way as fuller's earth, but higher concentrations of natural material were required to produce the same level of response. The effect of finely divided solids on fish was dependent on concentration, particle-size distribution, and angularity of the suspended particles. The cause of death was the same in all experiments--anoxia. This study provides base-line information for preproject decisionmaking based upon the anticipated concentration of suspended sediments at the project site and the effect of various lengths of exposure on estuarine fish of different life-history stages and habitat preference. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1976
- Accession Number
- ADA037377
Entities
People
- D. A. Neumann
- J. A. Sherk Jr.
- J. M. O'connor
Organizations
- University of Maryland