Copper-induced olfactory toxicity in salmon and steelhead: extrapolation across species and rearing environments

Recent research has shown that hatchery coho salmon (Oncorhynchus kisutch) are vulnerable to the olfactory neurotoxicity caused by copper from urban runoff, pesticide use, and mining activities. To explore the broader application of this data to salmonids living in the wild, we exposed naturally-reared steelhead (O. mykiss) to copper (5 and 20 μg/L; 3h) and measured losses in olfactory function via electro-olfactogram (EOG) recordings. Copper exposure disrupted the olfactory responsiveness of steelhead to an amino acid (L-serine) in a dose-dependent manner that was equivalent to previously published data for hatchery coho. Our findings support extrapolation of copper toxicity data across species and from fish raised in hatcheries to fish in the wild.