Which of the following is illegal to use while fishing?

Using antifreeze while fishing is illegal because it poses significant environmental and health risks. Antifreeze typically contains ethylene glycol, which is highly toxic to aquatic life and can cause severe harm to fish and other wildlife if introduced into their habitat. This illegal practice endangers not only the fish populations but also the overall ecosystem, as it can disrupt the food chain and water quality.

In contrast, options such as single hooks, weightless flies, and lead sinkers—while regulated—are generally permissible under various circumstances. Single hooks and weightless flies are common fishing tools used in many techniques, while lead sinkers, although they have restrictions concerning size and usage, are often allowed provided they follow specific guidelines. This regulation on sinker weight, for instance, exists primarily to reduce lead exposure to aquatic animals. Understanding these regulations helps maintain sustainable fishing practices while protecting the environment.