Michel Roggo / Brown trout (Salmo trutta fario) young trout with parr marks, Europe

Michel Roggo / Brown trout (Salmo trutta fario) Mountain creek, Fribourg Alps, Switzerland, 2005

Michel Roggo / Brown trout (Salmo trutta fario) Europe

Michel Roggo / Brown trout (Salmo trutta fario) Europe

Michel Roggo / Brown trout (Salmo trutta fario) Idrjica, Slovenia, 2006

Michel Roggo / Brown trout (Salmo trutta fario) River Doubs, France, 2005

Patricio Robles Gil / Four Brown trout (Salmo trutta) on ground, caught by sport fisherman, Small Xadutka River, Southern Kamchatka, Russia

Robert Thompson / Brown trout {Salmo trutta} Ballinderry River, County Tyrone, Republic of Ireland, March

Wild Wonders of Europe / Falklin / Brown trout (Salmo trutta) in shallow water, Bornholm, Denmark, November 2008

Wild Wonders of Europe / Falklin / Brown trout (Salmo trutta) migrating upstream over rocks, Bornholm, Denmark, November 2008

Wild Wonders of Europe / Falklin / Brown trout (Salmo trutta) migrating upstream, Bornholm, Denmark, November 2008

Wild Wonders of Europe / Falklin / Brown trout (Salmo trutta) with mouth wide open feeding on Mayfly (Ephemera Danica) Dala river, Götene, Västra Götaland, Sweden, May 2009

Wild Wonders of Europe / Falklind / Brown trout (Salmo trutta) with mouth wide open swallowing Mayfly (Ephemera Danica) Dala river, Götene, Västra Götaland, Sweden, May 2009

Wild Wonders of Europe / Falklind / Brown trout (Salmo trutta) catching a Mayfly (Ephemera Danica) Dala river, Götene, Västra Götaland, Sweden, May 2009

Wild Wonders of Europe / Falklin / Brown trout (Salmo trutta) in shallow water migrating upstream, Bornholm, Denmark, November 2008

Wild Wonders of Europe / Falklin / Brown trout (Salmo trutta) closing mouth around Mayfly (Ephemera Danica) Dala river, Götene, Västra Götaland, Sweden, June 2009

Tim Martin / Brown trout (Salmo trutta) rising to take insect from river surface. River Stour, Kent, UK. June

Tim Martin / Chub (Leuciscus cephalus) in foreground and Brown trout (Salmo trutta) behind it. River Stour, Kent, UK. June

Wild Wonders of Europe / Lundgren / Atlantic salmon (Salmo salar) or Brown / Sea trout (Salmon trutta) young fish, River Orkla, Norway, September 2008

Graham Eaton / Male Brown trout (Salmo trutta) in profile over gravel, Lancashire, UK, December

Graham Eaton / Male Brown trout (Salmo trutta) Lancashire, UK, December

Graham Eaton / Male Brown trout (Salmo trutta) Lancashire, UK, December

Graham Eaton / Female Brown trout (Salmo trutta) over gravel, Lancashire, UK, December

Graham Eaton / Female Brown trout (Salmo trutta) Lancashire, UK, December

Graham Eaton / Female Brown trout (Salmo trutta) Lancashire, UK, December

Graham Eaton / Female Brown trout (Salmo trutta) over gravel, Lancashire, UK, December 2008

Graham Eaton / Female Brown trout (Salmo trutta) over gravel, Lancashire, UK, December

Jane Burton / Brown trout {Salmo trutta} eggs and newly hatched alevins burrowing down into river gravel, captive, from Europe, life cycle sequence 7/14

Jane Burton / Brown trout {Salmo trutta} juvenile two-months-old fingerlings, holding their position in strong current, captive, from Europe, life cycle sequence 12/14

Jane Burton / Brown trout {Salmo trutta} eggs with eyes visible, ten days from hatching, captive, from Europe, life cycle sequence 1/14

Jane Burton / Brown trout {Salmo trutta} one-week-old alevin on river gravel, captive, from Europe, life cycle sequence 8/14

Jane Burton / Brown trout {Salmo trutta} juvenile two-months-old fingerling, holding its position in strong current, captive, from Europe, life cycle sequence 13/14

Jane Burton / Brown trout {Salmo trutta} one-week-old alevins on river gravel, captive, from Europe, life cycle sequence 9/14

Jane Burton / Brown trout {Salmo trutta} eggs ready to hatch, eyes and yolk-sacs visible, captive, from Europe, life cycle sequence 2/14

Jane Burton / Brown trout {Salmo trutta} one-week-old alevins on river gravel, captive, from Europe

Jane Burton / Brown trout {Salmo trutta} alevin hatching from eggs, captive, from Europe, life cycle sequence 3/14

Jane Burton / Brown trout {Salmo trutta} three/four-weeks-old alevins with freshwater Shrimp {Gammarus sp}, captive, from Europe, life cycle sequence 10/14

Jane Burton / Brown trout {Salmo trutta} newly hatched alevins and eggs ready to hatch, captive, from Europe, life cycle sequence 4/14

Jane Burton / Brown trout {Salmo trutta} three/four-weeks-old alevin, captive, from Europe

Jane Burton / Brown trout {Salmo trutta} newly hatched alevins and eggs ready to hatch, captive, from Europe, life cycle sequence 5/14

Jane Burton / Two Brown trout {Salmo trutta} juvenile two-months-old fingerlings, holding their position in strong current, captive, from Europe

Jane Burton / Two Brown trout {Salmo trutta} captive, from Europe, life cycle sequence 14/14

Jane Burton / Brown trout {Salmo trutta} two juveniles / par display forward parellel swimming, teritorial display, captive, from Europe

Jane Burton / Brown trout {Salmo trutta} and Freshwater crayfish, captive, from Europe

Jane Burton / Brown trout {Salmo trutta} and Freshwater crayfish, captive, from Europe

Jane Burton / Brown trout {Salmo trutta} three/four-weeks-old alevins, captive, from Europe

Jane Burton / Brown trout {Salmo trutta} newly hatched alevins and eggs ready to hatch, captive, from Europe, life cycle sequence 6/14

Jane Burton / Brown trout {Salmo trutta} three/four-weeks-old alevin, captive, from Europe, life cycle sequence 11/14

Jose B. Ruiz / Man fishing for Brown trout {Salmo trutta} in white waters, Libena, Picos de Europa, Spain

Jose B. Ruiz / Brown trout {Salmo trutta} dead in net, Lebena, Picos de Europa, Asturias, Spain

TIM MARTIN / River trout (Salmo trutta) captive, UK

Staffan Widstrand / European brook trout caught on flyfishing line Lapland, Sweden.

Jane Burton / River / Brown trout {Salmo trutta} eggs. Embryos visible. Captive. UK.

Jane Burton / River / Brown trout {Salmo trutta} eggs and alevins (fry). Captive. UK.

TIM MARTIN / River trout

TIM MARTIN / River trout, UK

TIM MARTIN / River trout (Salmo trutta) portrait, UK, captive

Adrian Davies / Brown river trout, 2 year-old {Salmo trutta fario} Farm bred UK

Paul Hobson / Brown trout {Salmo trutta fario} Derbyshire, UK

David Kjaer / Dead river trout floating at surface of polluted lake {Salmo trutta} Wiltshire, UK

Rob Jordan / 2020VISION / Young Brown trout (Salmo trutta), with parr marks being measured to monitor population, density, health of the fish and water quality of the River Whiteadder, before being released back into the river...

Rob Jordan / 2020VISION / Bucket containing small Brown trout (Salmo trutta) and Atlantic salmon (Salmo salar) captured and released to monitor size, population, density and health of the fish, and water quality, River Whitead...

Rob Jordan / 2020VISION / Scientist Kenny Galt (right) and assistant Fraser Brown electro fishing for Atlantic salmon (Salmo salar) and Brown trout (Salmo trutta) parr on the River Whiteadder to monitor population, density and...

Rob Jordan / 2020VISION / Landscape view of the River Whiteadder, a tributary of the River Tweed, with two scientists walking along the bank carrying electro fishing equipment to monitor population, density and health of Atlan...

Rob Jordan / 2020VISION / Landscape view of the River Whiteadder, a tributary of the River Tweed, with two scientists downstream electro fishing to monitor population, density and health of Atlantic salmon (Salmo salar) and Br...

Rob Jordan / 2020VISION / Landscape view of the River Whiteadder, a tributary of the River Tweed, with two scientists walking along the bank carrying electro fishing equipment to monitor population, density and health of Atlan...

Rob Jordan / 2020VISION / Scientist Kenny Galt (right) and assistant Fraser Brown electro fishing for Atlantic salmon (Salmo salar) and Brown trout (Salmo trutta) parr on the River Whiteadder to monitor population, density and...

Rob Jordan / 2020VISION / Two young Brown trout (Salmo trutta), with parr marks being measured to monitor population, density, health of the fish and water quality of the River Whiteadder, before being released back into the r...

Rob Jordan / 2020VISION / Scientist Kenny Galt (right) and assistant Fraser Brown electro fishing for Atlantic salmon (Salmo salar) and Brown trout (Salmo trutta) parr on the River Whiteadder to monitor population, density and...

Rob Jordan / 2020VISION / Scientist Kenny Galt (left) and assistant Fraser Brown electro fishing for Atlantic salmon (Salmo salar) and Brown trout (Salmo trutta) parr on the River Whiteadder to monitor population, density and...

Rob Jordan / 2020VISION / Scientist Kenny Galt (left) and assistant Fraser Brown electro fishing for Atlantic salmon (Salmo salar) and Brown trout (Salmo trutta) parr on the River Whiteadder to monitor population, density and...

Rob Jordan / 2020VISION / Derek Purvis (left) and another boatman preparing a boat and nets for a 'run' on the River Tweed, casting the net to catch migratory Atlantic salmon (Salmo salar) and Sea trout (Salmo trutta) for moni...

Rob Jordan / 2020VISION / Equipment used by Tweed Foundation staff whilst netting and tagging migratory Atlantic Salmon (Salmo salar) and Brown trout (Salmo trutta) for monitoring fish movement, density and biology on the Rive...

Rob Jordan / 2020VISION / Staff of the Tweed Foundation hauling nets after a 'run' on the river, casting the net to catch migratory Atlantic salmon (Salmo salar) and Brown trout (Salmo trutta) for monitoring, River Tweed, Berw...

Rob Jordan / 2020VISION / Extracting fish caught in Tweed Foundation nets by scientists and staff tagging migratory Atlantic salmon (Salmo salar) and Brown trout (Salmo trutta) to monitor fish movement, density and biology, Ri...

Rob Jordan / 2020VISION / Atlantic salmon (Salmo salar) and Brown trout (Salmo trutta) parr identification signs in a fishing shelter on the River Tweed, Berwickshire, Scotland, UK, August

Rob Jordan / 2020VISION / Atlantic salmon (Salmo salar) and Brown trout (Salmo trutta) identification signs in a fishing shelter on the River Tweed, Berwickshire, Scotland, UK, August

Rob Jordan / 2020VISION / Boatman rowing on the River Tweed rowing trailing nets for a 'run' on the river to catch migratory Atlantic salmon (Salmo salar) and Brown trout (Salmo trutta) for monitoring by The Tweed Foundation s...

Rob Jordan / 2020VISION / Fish tags used by Tweed Foundation scientists for tracking migratory Atlantic salmon (Salmo salar) and Brown trout (Salmo trutta) to monitor fish movement, density and biology, River Tweed, Berwickshi...

Rob Jordan / 2020VISION / Tweed Foundation staff hauling in nets after a 'run', casting the net to catch migratory Atlantic salmon (Salmo salar) or Brown trout (Salmo trutta) for tagging, River Tweed, Berwickshire, Scotland, U...

Chris Shields / Illustration of Dipper (Cinclus cinclus) with~Brown trout (Salmo trutta) in foreground.

David Woodfall / Sea / Brown trout (Salmo / morpha trutta) with Environment Agency tags prior to smoking process. Connections to the Severn Estuary and traditional salmon fishing. Wye and Severn Smokery, Gloucestershi...