Pesticides impair salmons' sense of smell.
Tierney KB, JL Sampson, PS Ross, MA Sekela and CJ Kennedy. 2008. Olfaction is impaired by an environmentally realistic pesticide mixture. Environmental Science and Technology 42:4996–5001.
A mix of pesticides that mimics those found in a natural environment lowers a salmon's sense of smell. The fish rely on their noses to find mates and food and navigate around the oceans. Less keen smell may affect their abiltiy to mate, eat and migrate. These impacts may be contributing to the global decline of ocean fish populations. Here, for the first time, scientists mimicked the real world by exposing fish to a relevant mixture of pesticides for several days. Following the exposure, they assessed the fish's sense of smell by measuring electrical activity in the fish noses. All the doses of pesticides impaired electrical activity (sense of smell) in the fish nose. While several other studies show that pollutants can impair a fish’s sense of smell, the ecological relevance of those studies have been questioned. Most of them used high doses of pollutants, tested single pollutants, and exposed fish to pollutants for short periods only.