Photographs and plan: Water dam at Llyn Pwmp, Llangefni

PHOTOGRAPHS AND PLAN: Water dam at Llyn Pwmp, Llangefni with details of the salmon ladder and fish pass.

A fish ladder, also known as a fishway, fish pass or fish steps, is a structure on or around artificial and natural barriers (such as dams, locks and waterfalls) to facilitate diadromous fishes' natural migration as well as movements of potamodromous species. Most fishways enable fish to pass around the barriers by swimming and leaping up a series of relatively low steps (hence the term ladder) into the waters on the other side. The velocity of water falling over the steps has to be great enough to attract the fish to the ladder, but it cannot be so great that it washes fish back downstream or exhausts them to the point of inability to continue their journey upriver.

Dim cyfyngiadau/ No Restrictions

Adnau preifat / Private deposit

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Mae copiau clawr caled o`r catalogau ar gael yn Archifau Ynys Môn ac yn y Gofrestr Cenedlaethol Archifau. Polisi Archifau Ynys Môn yw catalogio yn iaith y ddogfen./Hard copies of the catalogue are available at Archifau Ynys Môn / Anglesey Archives and the National Register of Archives. It is the policy of Archifau Ynys Môn / Anglesey Archives to catalogue in the language of the document.

Cyflwr da /Good condition

Compiled by Amanda Sweet for Archifau Ynys Môn / Anglesey Archives

https://en.wikipedia.org/wiki/Fish_ladder

Mae'r holl gofnodiadau sy'n cydymffurfio â pholisi casglu Swyddfa Gofnodi Cyngor Sir Ynys Môn wedi eu cadw /All records which meet the collection policy of the Anglesey Archives have been retained.

Ni ddisgwylir croniadau/Accruals are not expected