This is at the mouth of one of the many river systems on the west coast of Cape York Australia. Bull Sharks can be found all over Australia including in fresh water river systems (mothers will travel upstream to have their pups).
However they are particularly prominent in areas such
as where this was filmed. During the run off (just after the wet season)
large numbers come to feed at the outlets of these river systems. On
this trip we counted seven swimming around the boat (lured in by the
fish we had been catching). In these situations it is almost impossible
to catch a fish as the sharks eat them before you can get them onboard.