First find the number of fish the gharials need to eat: 9 gharials * 15 fish/gharial = <<9*15=135>>135 fish
Then find the number of frogs by multiplying that quantity by the number of frogs per fish: 135 fish * 8 frogs/fish = <<135*8=1080>>1080 frogs
Then multiply the number of frogs by the number of flies each frog eats to find the number of flies: 1080 frogs * 30 flies/frog = <<1080*30=32400>>32,400
#### 32400