Fishing Weir - History

History

In medieval Europe, large fishing weir structures were constructed from wood posts and wattle fences. 'V' shaped structures in rivers could be as long as 60 m and worked by directing fish towards fish traps or nets. Such fish traps were evidently controversial in medieval England. The Magna Carta includes a clause requiring that they be removed:

All fish-weirs shall be removed from the Thames, the Medway, and throughout the whole of England, except on the sea coast.

Basket weir fish traps were widely used in ancient times. They are shown in medieval illustrations and surviving examples have been found. Basket weirs are about 2 m long and comprise two wicker cones, one inside the other—easy to get into and hard to get out.

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. An example of such a fishing weir was at Rhos Fynach in North Wales, which survived in use until World War I.

An enormous series of fish weirs, canals and artificial islands was built by an unknown pre-Columbian culture in the Baures region of Bolivia, part of the Amazonian savannah. These earthworks cover over 500 square kilometres (190 sq mi), and appear to have supported a large and dense population around 3000 BCE. See also Dr. Erickson's research website. An approximate location for these sites is 63.4128° W, 13.4812° S.