If you fish, petroleum-based fishing line can be a menace and even lethal to fish, aquatic wildlife and birds if it gets loose and strewn in lakes and other waterways. When buying new fishing line, avoid petroleum-based plastic lines and look for new biodegradable ones instead. If the biodegradable line gets lost in the water, it will degrade quickly with just small amounts of carbon dioxide and water. But even with biodegradable fishing line, be sure to still bring the old fishing line back with you and dispose of it properly. Even during the biodegrading process, it can still be harmful to aquatic wildlife.