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Craig A. Stow

Publications and source records attributed to Craig A. Stow.

20 records · Page 2Linked to original sources

Fisheries management to reduce contaminant consumption

This paper concludes that contaminants in Lake Michigan fishes are likely to remain above detectable levels for some time. Some interest groups have called for measures ranging from additional effluent controls to a ban on the industrial use of chlorine. Such measures, however well intended, are likely to have little impact on many of the contaminants of primary concern. PCBs, in particular, are largely the legacy of past activities and are not likely to be substantially affected by additional regulation. The authors review several options for reducing human exposure to PCBs, using relatively simple fisheries manipulations, although they do not propose that these measures are the ultimate solution to the contaminant problem. Of the options presented, the most promising is the replacement of lake trout with less-contaminated species, such as rainbow trout.

BioScience

Evidence that PCBs are approaching stable concentrations in Lake Michigan fishes

We examined PCB concentration data for seven species of Lake Michigan fishes to determine what trends were apparent °20 yr after PCB restrictions became effective. Total PCB concentrations in all seven species, lake trout (Salvelinus namaycush), rainbow trout (Oncorhynchus mykiss), brown trout (Salmo trutta), chinook salmon (Oncorhynchus tshawytscha), coho salmon (Oncorhynchus kisutch), alewife (Alosa pseudoharengus), and bloater chub (Coregonus hoyi) declined and appeared to stabilize in the mid-to-late 1980s. Concentrations in two species, chinook and coho salmon, appear to have increased slightly since the late 1980s. All species are currently well below the high PCB levels that existed when PCB use was curtailed in the 1970s. We believe stabilizing concentrations are the result of large pools of PCBs that are being recycled in the environment. Atmospheric and sediment PCB inputs to the lake probably constitute current PCB sources. Increasing concentrations in chinook and coho salmon are likely the result of changing growth dynamics caused by alterations in the mid-trophic levels of the food web. Median stable PCB concentrations estimated in this analysis are below the current FDA action level of 2 mg/kg, but not appreciably below this threshold. Improvements beyond these levels may result if management practices that maximize fish growth rates are implemented. Detection of future improvements in PCB levels may require samples in the range of 1000-2000 fish because of the high variability in PCB concentrations among individuals.

Ecological Applications