Charlie can answer this better than me.
But, briefly, sharks are very rare in Hong Kong – and it may be that right now, there aren’t any dangerous sized ones in Hong Kong (or even close by): shark fin business helped ensure this.
A few years ago, there were a few attacks, with some people killed [article on this site], but just possibly only one shark involved (migrating into area; and maybe not much fish to eat?).
There are shark nets protecting most of main swimming beaches, so keep in these if you’re still concerned – but I guess that if a shark does happen by, it may well be sighted quickly, or you would be v unlucky to be its first bite. :ohmy: