Swackhamer, D.L., Ongoing.   Effect of Bythotrephes on PCB Biomagnification in Salmonids,  University of Minnesota Sea Grant College Program

Effect of Bythotrephes on PCB Biomagnification in Salmonids

Objectives:
We will test the hypothesis that predation on Bythotrephes (BC) by alewife is increasing the contaminant burden of alewife, which in turn is responsible for the constant and/or increasing levels of PCBs in coho salmon and lake trout in Lake Michigan. We will meet the following objectives: 1. Determine PCB congener concentrations in all components of the alewife foodweb; 2. Verify the trophic levels of the foodweb samples using stable isotope analysis; 3. Estimate alewife PCB concentrations from foodweb models and our measured input data, and compare them to our measured alewife concentrations. Sampling and model runs will include mid-summer (BC absent) and late summer (BC abundant) scenarios. and 4. Estimate lake trout and coho salmon PCB concentrations and compare to measured concentrations, and to published trend data.

Methodology:
We will collect samples from all of the trophic levels in the alewife foodweb and analyze them for PCB congeners. Samples will be collected in midsummer before BC are abundant, and late summer when they are very abundant. PCBs are chosen because of their environmental relevance, their range of physical chemical properties, and because they biomagnify in foodwebs. The observed alewife concentrations will be compared statistically to concentrations predicted using foodchain models that incorporate BC as an additional trophic level, and to predictions without the BC trophic level.

Entire Paper
Contact: D. L. Swackhamer, Environmental and Occupational Health, Box 807 UMHC, 420 Delaware St. S. E., University of Minnesota Minneapolis, MN 55455 or dswack@mail.eoh.umn.edu
Keywords: Bio-accumulation, Ongoing_project, Bythotrephes
Product Type: Environmental_impacts, Research
User Type: Resource_management