While bottom trawling—a fishing method that drags a large net with heavy weights across the seafloor—fishermen often catch more than their target fish. Here, they've scooped up a large deep-sea coral, which is likely centuries old. While this method is good at catching lots of fish, it also does a lot of damage along the way because it captures everything in its path, even digging into the seafloor. Many creatures end up mistakenly caught and thrown overboard dead or dying. This is known as bycatch, and can amount to 90% of a trawl’s total catch. In addition, the trawl can destroy large areas of seafloor habitats that give marine species food and shelter.