Ancient fish traps

I was reading about ancient ways to fish,

usually we think of "hunter gatherers" as fighting mammoths, but fish and shellfish were also used in the good old days.

one way to catch fish was to use fishing weirs: Wikipedia article:

A fishing weir, fish weir, fishgarth[1] or kiddle is an obstruction placed in tidal waters, or wholly or partially across a river, to direct the passage of, or trap fish. A weir may be used to trap marine fish in the intertidal zone as the tide recedes, fish such as salmon as they attempt to swim upstream to breed in a river, or eels as they migrate downstream. Alternatively, fish weirs can be used to channel fish to a particular location, such as to a fish ladder. Weirs were traditionally built from wood or stones.

how far back were they used?

Well, when the Europeans arrived in Australia (before they chased the aborigines into the less desirable dryer bush areas), the aborigines used fish weirs: And some of them date back thousands of years: Locals claim they date back 40 000 years but that is unproven.

UKGuardian article about the controversy.

Located in north-west New South Wales, the traps lie where the Barwon river makes a curve near the largely Aboriginal town of Brewarrina. When the water level is low, bulrushes grow tall as waist-high and the sun bears down on exposed rocks – ordinary rocks, arranged in an unusual way.

The rocks surround 12 teardrop-shaped pools across half a kilometre. In the past, fish were herded in through small openings that the locals would quickly close shut with a few rocks. The pen walls are at different heights, allowing them to be used at different water levels, and have proved resistant to damage in the face of high and fast water...

“Fish traps became prominent across Australia – from the Torres Strait islands to south-east Australia – during the past few thousand years, suggesting interconnections across tens of thousands of miles. Life in pre-European Australia was a hell of a lot more complex than we might think,” he says.

and when one reads about those "lost" primitive Amazon tribes, one should remember that these are the survivors of the European disease disaster, and that their ancestors were not that primitive, but had sophisticated villages with raised platforms for agriculture and fish weirs:

UPenn article describes them. 

One artificial feature, referred to as a zigzag earthwork, particularly intrigued me. Low earthen walls zigzag across the savannas between forest islands (Fig. 2). Because of their changing orientations, they did not make sense as roads between settlements.

As we mapped them with tape measure and compass, I noted that there were small funnel like opening where the earthworks changed direction. I immediately realized that these matched the description of fish weirs that are reported in the ethnographic and historical literature on Amazonian peoples. Fish weirs are fences made of wood, brush, basketry, or stones with small openings that extend across bodies of water. Baskets or nets are placed in the openings to trap migrating fish.

While most fish weirs are simple ephemeral structures crossing a river or shallow lake, those of Baures are permanent earthen features covering more than 500 square kilometers. In addition, small artificial ponds are associated with the fish weirs

: Pre-Columbian fish weirs and ponds in the savannas of Baures, Bolivia

(painting by Dan Brinkmeier, Field Museum of Natural History

similar structures were in North America also.

Smithsonian has an article on Taiwan's tidal fish weirs.

Science Direct article on fish wiers. and why they work.

Primitivesurvival has a video on how to make one: