For decades fish and game agencies have attempted to restore native fish…
…and to get rid of non-native fish in targeted streams and lakes. One common method is to use fish poisons – called piscicides – primarily Rotenone and Antimycin A. In many cases the same non-native fish being targeted for removal were originally stocked by fish and game agencies decades earlier.
Fisheries managers say Rotenone and Antimycin A have been used successfully to restore native, sometimes endangered, fish to their traditional habitats. They say without the poisons it would be impossible to reclaim streams for natives.
Opponents say fisheries managers don’t fully evaluate the risk of the piscicides to non-target aquatic species such as amphibians, reptiles, insects and macroinvertebrates, some of which may also be endangered. Using piscicides in pristine, headwater steams is especially troubling, and there are many who fear the cumulative impact the poisons may have on water quality and human health.
In most cases the repeated use of poisons hasn’t stopped non-natives and hybrids from reappearing in previously poisoned systems, either due to incomplete poisoning, natural migration, game department mistakes in stocking, and/or re-introduction of non-natives by citizens.