Assessing risks to population dynamics of aquatic animals from dredged materials

Scott Ferson, H. Resit Akçakaya, Pedro Silva

Funded by Army Corps of Engineers Waterways Experiment Station

Project Description

        Daphnia magna and the polychaete (Neanthes arenaceodentata) are widely used to monitor the toxicity of dredge spoils. Traditionally measured variates such as acute mortality, depression of fecundity, and rate of developmental abnormalities are difficult to interpret and present a confusing array of 'endpoints' to decision makers. Applied Biomathematics developed population-level models for the two species to develop a sensible scheme to express impacts in terms of the entire population's dynamics. Because the populations are grown under controlled laboratory conditions, environmental variability is minimal. However, measurement error is still often quite large, and the uncertainty it induces must be propagated by the model to determine the reliability of the final assessment. The results of the project are described in the following publications.

Bridges, T.S., R.B. Wright, B.R. Gray, A.B. Gibson and T.M. Dillon. 1996. Chronic toxicity of Great Lakes sediments to Daphnia magna: elutriate effects on survival, reproduction and population growth. Ecotoxicology 5:83-102.

Ferson, S., L.R. Ginzburg and R.A. Goldstein. 1996. Inferring ecological risk from toxicity bioassays. Water, Air and Soil Pollution. 90:71-82.