This is from an article awhile back. Came across and find it interesting.
From Comments: “We have similar fish traps around the southernmost tip of Africa. Some are believed to be “ancient” and some we know were built during late 1700 early 1800 when Europeans left the Cape and settled in this region. The ancient ones were, in my opinion, originally built by the Portugese late 1400’s – who were shipwrecked along the coast…”