Dale Sutton / 2020VISION / Adult Daubenton's bat (Myotis daubentoni) flying over a weir, England, UK, September. 2020VISION Exhibition. Did you know? This species is know as the 'water bat', and catches insects from the water s...

Linda Pitkin / 2020VISION / Brown trout (Salmo trutta) in turbulent water at a weir, River Ettick, Selkirkshire, Scotland, UK, October

Andy Rouse / 2020VISION / European river otter (Lutra lutra) climbing to the top of a weir, river, Dorset, UK, November

Andrew Parkinson / Pair of Greylag geese (Anser anser) and chicks spotlit by dawn sunlight near a small weir. Nottinghamshire, UK, May (non-ex)

Ann & Steve Toon / Atlantic salmon (Salmo salar) smolt trap on the Kielder burn, Northumberland, UK, April 2012

Ann & Steve Toon / Atlantic salmon (Salmo salar) people collecting smolts from smolt trap on Kielder burn, Northumberland, UK, April 2012

Luke Massey / 2020VISION / Female European river otter (Lutra lutra) playing with two cubs near a weir, Hertfordshire, England, UK, February

Luke Massey / 2020VISION / Female European river otter (Lutra lutra) playing with cub near a weir, Hertfordshire, England, UK, February

Nick Upton / Pulteney bridge and weir, Bath, Somerest, UK, April 2011.

Nick Upton / Looking down on a Lesser black-backed gull (Larus fuscus) bathing in the River Avon on the edge of Pulteney weir, Bath, Somerset, UK, April.

Nick Turner / Abbey Mill and weir on the River Avon, Tewkesbury, Gloucestershire, UK, July 2008.

Andy Rouse / European Otter (Lutra lutra) walking down the steps of a weir. Wales, UK, December.

Andy Rouse / 2020VISION / European river otter (Lutra lutra) jumping down weir, Dorset, UK, December

Andy Rouse / 2020VISION / European river otter (Lutra lutra) jumping down weir, Dorset, UK, December

Andy Rouse / 2020VISION / European river otter (Lutra lutra) swimming in river just above a weir, Dorset, UK, November

Andy Rouse / 2020VISION / European river otter (Lutra lutra) climbing weir in river, Dorset, UK, November

Andy Rouse / 2020VISION / European river otter (Lutra lutra) climbing weir on river, Dorset, UK, November

Andy Rouse / 2020VISION / European river otter (Lutra lutra) by weir in river, Dorset, UK, November

Andy Rouse / 2020VISION / European river otter (Lutra lutra) at the bottom of a weir in river, Dorset, UK, November

Andy Rouse / 2020VISION / European river otter (Lutra lutra) in river looking at weir, Dorset, UK, November

Ernie Janes / Hambleden mill and weir on the River Thames, Buckinghamshire, UK

Shattil & Rozinski / Fishing weir from early settlement of First Nation peoples of British Columbia's Great Bear Rainforest, Canada, September 2010

Shattil & Rozinski / Fishing weir from early settlement of First Nation peoples of British Columbia's Great Bear Rainforest, Canada, September 2010

Dietmar Nill / Mallard {Anas platyrhynchos} drake standing at top of weir, Germany

Nick Upton / River Avon in spate flowing over Bathampton weir and past Bathampton Mill pub, near Bath, Somerset, UK. November 2009

Nick Upton / River Avon in spate flowing under Bathampton Toll bridge, over weir and past Bathampton Mill pub, near Bath, Somerset, UK. November 2009

Tim Laman / Rubbish clogs a mangrove channel in Bali, where trash is still disposed of in rivers. Sanur vicinity, Bali, Indonesia. May 2006

Ross Hoddinott / Porlock Weir, weathered groyne and sunrise, looking toward Bossington, Exmoor National Park, Somerset, UK. October 2008.

Larry Michael / Autumnal colours reflected on water over weir.

Christian Ziegler / Weir dam built to measure the rate of water flow, Lutz Creek, Barro Colorado Island, Panama

Onne van der Wal / Two young Kodiak bears (Ursus arctos middendorffi) playing at a weir in Alaska, USA, 2001.