Exposure to waterborne Cu inhibits cutaneous Na+ uptake in post-hatch larval rainbow trout (Oncorhynchus mykiss).

Highlights: [•] Na+ uptake and ammonia excretion shift from skin to gills over post-hatch development. [•] Waterborne Cu inhibits Na+ uptake by the skin only in early development (3dph). [•] By late development (25dph), Cu inhibits both gill Na+ uptake and ammonia excretion. [•] The skin is the likely site of Cu toxicity immediately following hatch. [•] This shift in site and possible mechanism of toxicity has implications for the BLM. [Copyright &y& Elsevier]