The Westland Petrel (Procellaria westlandica) population is thought to have increased significantly in recent decades, perhaps as a result of increased food in the form of waste from fishing vessels. A survey of Westland Petrels off the West Coast of the South Island, New Zealand, showed that fishing vessels in the West Coast South Island Hoki (Macruronus novaezelandiae) fishery influence the distribution of Westland Petrels, but only a small proportion of the Westland Petrel population appears to utilise this fishery waste at any one time. Westland Petrels appear to select foraging areas primarily on natural features, such as water depth, and only if fishing vessels are in the same area are Westland Petrels attracted to them.