Fishing nets that are lost or discarded by fishing boats become a significant entanglement risk for reef fish living nearby. Nets that settle on reefs can also cause large scale damage to coral structures and other benthic organisms (organisms living on reef substrates). Fish that become entangled in abandoned or discarded nets often attract predators to feed on them, increasing the likelihood of the predatory fish also becoming entangled. In addition to these immediate risks, nets that have settled over a substrate for a long duration of time may also prevent certain types of corals from growing in that area.
A number of submerged pinnacle reefs can be found surrounding the island of Koh Tao, some of which exist in deeper waters, several kilometres offshore. These deeper pinnacles commonly attract large schools of pelagic fish, and as a result, often experience fishing nearby.