Tree-lined Aberdeen Promenade runs from west to east on Aberdeen Praya Rd across the water from Ap Lei Chau. On its western end is sprawling Aberdeen Wholesale Fish Market with its industrial-strength water tanks teeming with marine life. It's pungent and grimy, but 100% Hong Kong. Before reaching the market, you'll pass berthed house boats and seafood-processing vessels. (We detected a karaoke parlour or two as well.)
The eastern end of Aberdeen Promenade is where you get on a boat for Ap Lei Chau. The best way to explore the harbour is by sampan. A half-hour tour of the typhoon shelter costs HK$60 to HK$80 per person. Ferries depart multiple times a day for Lamma Island and Cheung Chau from here, and about twice a week for Po Toi Island.