Which piscicide is the only one registered for control of fish populations in Washington?

Rotenone is recognized as the only piscicide registered for controlling fish populations in Washington. This is due to its specific effectiveness in selectively targeting fish by interfering with their respiration. As a natural compound derived from the roots of certain tropical plants, rotenone disrupts the process of cellular respiration in fish, leading to their elimination from a body of water.

The use of rotenone is carefully regulated, given its potential environmental impact and the need for responsible application to prevent harm to non-target organisms and ecosystems. This regulation aligns with conservation efforts and legal requirements in Washington aimed at managing aquatic environments, especially in the context of invasive fish species or habitat restoration projects.

Other substances mentioned, such as pyridine, carbaryl, and endosulfan, are not registered for use as piscicides in Washington. These chemicals may have different applications in agriculture or pest control, but they do not have the same targeted action against fish populations that rotenone does. Understanding the specific roles and registrations of various chemicals for specific purposes is crucial in environmental management and helps ensure the health of aquatic ecosystems.