Like many marine predators, pilot whales are susceptible to entanglement and bycatch in pelagic fishing gear, such as gill nets, long lines and some trawl fisheries. Once entangled or hooked, whales may drag the gear behind them for long distances, resulting in fatigue, compromised feeding ability, or injury, often leading to reduced reproductive success and death. Pilot whales are also susceptible to vessel strikes, which can be lethal, or lead to injury and behavioural changes. As top predators, pilot whales also suffer from the bioaccumulation of contaminants such as heavy metals and organichlorines in their tissues, which can have serious long-term impacts on health and reproduction, and is a rising concern in cultures that consume pilot whale meat. Short-finned pilot whales off the west coast of the US were found to have high amounts of DDT and PCB, however the levels were lower in whales from Japan and the Antilles.