New York state is taking steps to control the population of parasitic sea lampreys around Seneca Lake to protect other fish species.
The state's Department of Environmental Conservation says that next week it will begin treating tributaries of Seneca Lake with a chemical that kills lamprey larva but is harmless to most other aquatic wildlife.
When they grow up the lampreys become parasitic, preying on trout and salmon.
The chemicals have been used for decades to control the lamprey population.
The chemicals pose no threat to humans, but the state warns people not to fish or swim in the affected areas immediately following the treatment as a precaution. Signs will be posted along affected streams.