The structure pictured above is the Twin Heart Stone Weir on the island of Cimei, in the Penghu archipelago of Taiwan. There are hundreds of such weirs on these islands; the one pictured is the most famous because of the shape of the structure.
Fishing weirs have been used since prehistory in locations all around the world. In Europe they were traditionally constructed of wooden posts and wattle.
In the UK the traditional form was one or more rock weirs constructed in tidal races with a small gap that could be blocked by wattle fences when the tide turned to flow out again. Surviving examples, but no longer in use, can be seen in the Menai Strait. Because they were so effective they reduced inshore fish stocks and in 1861 Parliament banned their use except where they could be shown to have been in use prior to the Magna Carta.In North America, native americans traditionally used wooden weirs to trap salmon in rivers and tidal estuaries.
Credit to Arbroath for the heads-up on the subject.