The Ganges basin supports major fisheries, but these have declined in recent decades. In the Allahabad region in the middle section of the basin, catches of carp fell from 424.91 metric tons in 1961–1968 to 38.58 metric tons in 2001–2006, and catches of catfish fell from 201.35 metric tons in 1961–1968 to 40.56 metric tons in 2001–2006. In the Patna region in the lower section of the basin, catches of carp fell from 383.2 metric tons to 118, and catfish from 373.8 metric tons to 194.48. Some of the fish commonly caught in fisheries include catla (Catla catla), golden mahseer (Tor putitora), tor mahseer (Tor tor), rohu (Labeo rohita), walking catfish (Clarias batrachus), pangas catfish (Pangasius pangasius), Bagarius (Bagarius), Snakehead (fish) (Channa), bronze featherback (Notopterus notopterus) and milkfish (Chanos chanos).
Question: How many varieties of fish are commonly caught in the fisheries?
Answer: 10