Heavy rain can result in high sediment-levels in rivers and land runoff, and can contain bacterial contamination from livestock. This can result in mussel-farming areas being closed to harvesting. Applications to increase mussel farms in Admiralty Bay have been successfully opposed on the grounds that the area is a special feeding site for the dusky dolphin. A claim has been made, and a study carried out in New Zealand, that marine farms may affect the feeding ability of Dusky dolphins which round up shoals of schooling fish such as pilchard. The farming of Chinook Salmon also occurs in the outer Pelorus, with sites at Bulwer and the Waitata Reach. Salmon farming in the sounds is likely to expand in future years into the Cook Strait.