Hold Triangle + Circle + Square + X + R1 + R2 at the lure selection screen. Go to practice mode, then go to the next island on your right. Go to the hus where you will find many very big fish.
To unlock Kitaura Lake catch 100 fish.
Press Up, Up, Down, Down, L1, R1, L1, R1, X, Circle at the title screen. A sound will confirm correct code entry. Press Select at the options screen to view your stats.
To unlock Yamanaka Lake catch 150 fish.