Publication Summary

Recurrent mortality of coho salmon (Oncorhynchus kisutch) at Maritime Heritage Fish Hatchery was studied from 1987-1989. Hatchery water is supplied by Whatcom Creek, an urban stream which drains downtown Bellingham. Mortality typically coincides with first-flush storm events, suggesting that toxicants in runoff to Whatcom Creek may be responsible. Conventional and priority pollutant scans of hatchery water, taken during kill episodes, showed that copper, lead, and zinc were the only substances detected in amounts above federal toxicity criteria.

Recurrent mortality of coho salmon (Oncorhynchus kisutch) at Maritime Heritage Fish Hatchery was studied from 1987-1989. Hatchery water is supplied by Whatcom Creek, an urban stream which drains downtown Bellingham. Mortality typically coincides with first-flush storm events, suggesting that toxicants in runoff to Whatcom Creek may be responsible. Conventional and priority pollutant scans of hatchery water, taken during kill episodes, showed that copper, lead, and zinc were the only substances detected in amounts above federal toxicity criteria.

Metals concentrations were below LC50 values, possibly due to late sampling during storm events. However, additive or synergistic metals toxicity cannot be discounted. Histopathological examination of moribund coho revealed no evidence of infection or disease, but a proliferation of chloride cells in gill tissue may have been induced by metals contamination.

We recommend confirmatory sampling for metals in water and further pathological study.