The rivers and dams are stocked with trout from nearby hatcheries. In commercial production, breeder farms supply eggs to hatcheries. Other plants include feed mills, hatcheries, farms and tanneries. Hatcheries, fisheries and packing plants are mostly located south of Puerto Montt. Rainbow trout, especially those raised in farms and hatcheries, are susceptible to enteric redmouth disease. Sodium silicate gel is also used as a substrate for algal growth in aquaculture hatcheries. Tiger trout can be produced reliably in hatcheries. Agriculture, forestry, hydropower generation and fish hatcheries dominate catchment land use. In 1988, fertilized paddlefish eggs and larvae from Missouri hatcheries were first introduced into China. Specialised feeds are produced for fish hatcheries. Fish populations are now sustained by several tribally-run fish hatcheries and state and federal agencies. Breeding programmes have produced improved stock that is available from hatcheries. Integrators generally own breeder flocks, hatcheries, feed mills, and processing plants. These "Loch Leven" brown trout were distributed to the same hatcheries. An alternative method to hatcheries is to use spawning channels.