White sucker (Catostomus commersoni) collected from a site receiving primary-treated bleached kraft mill effluent (BKME) were older and had a higher condition factor than fish at a reference site and grew more slowly than fish from three other areas of Lake Superior. The BKME-exposed fish also exhibited an increased age to maturity, smaller gonads, lower fecundity with age, an absence of secondary sex characteristics in males, and females failed to show an increase in egg size with age. Lower serum estradiol and testosterone concentrations and greater hepatic mixed-function oxidase (MFO) activity, as measured by conversion of diphenyloxazole and benzo[ajpyrene were also observed in the BKME-exposed fish. The level of MFO activity varied with season; differences could not be detected between sites during the spring spawning period, but were markedly elevated (up to ninefold) at the BKME site during the summer. The poorer performance of fish at the BKME site appears to be related to decreased levels of serum steroids and consequent abnormalities in reproductive development and carbohydrate metabolism, although the relationship of the changes in steroid levels with the increased hepatic enzyme activity remains to be established.

No abstract

The Canadian Environmental Assessment Act (CEAA) defines the federal environmental assessment (EA) process for evaluating the likelihood that development projects (e.g., roads, buildings, factories) will have impacts on the environment. Environmental effects monitoring (EEM) programs for mining and pulp and paper mills under the Federal Fisheries Act, define the process that is to be used to evaluate existing effects caused by liquid effluents discharged by operating facilities. The EA process occurs before a project is approved, and involves predicting whether the project is going to cause significant environmental impacts. The EEM process occurs after a project is operational, and involves determining whether an existing project has had or is continuing to have significant impacts on the environment. Ideally, the processes are complimentary, with the EA process identifying environmental attributes considered important, and the EEM process demonstrating whether predicted or unpredicted impacts occurred. The two processes are usually done in isolation so potential synergies are lost. The point of this manuscript is to justify bridging the two processes. We use the aquatic environment as the example, and briefly describe the EEM process, aquatic environment indicators, experimental designs, and typical environmental thresholds, to illustrate how the EEM and EA processes link.

No abstract

Our recent studies have demonstrated reproductive dysfunction in white sucker (Catostomus commersoni), longnose sucker (C. catostomus) and lake whitefish (Coregonus clupeaformis) populations exposed to bleached kraft mill effluent (BKME). Although all three species show elevated levels of hepatic mixed function oxygenase (MFO) activity and depressed circulating steroid levels, we have been unable to provide clear evidence of whether these two events are directly linked to whole organism changes. Although depressed steroid levels appear to be linked to delayed sexual maturity, changes in fecundity and reduced secondary sexual characteristics in white sucker and lake whitefish, longnose sucker show no impacts of reduced steroid levels on reproductive performance. Installation of secondary treatment at this pulp mill did not alleviate the steroidal dysfunction or MFO induction. However, samples collected after a two week maintenance shutdown showed a return to reference levels of MFO activity in both sexes and of steroid levels in male fish. The relationship between elevated MFO activity and depressed steroid levels is unclear, but detailed experiments suggest that the two phenomena are not directly linked. White sucker show depressed steroid production and impaired reproductive regulation independent of MFO activity.