Brown Trout

Statistics

Length: 50-80cm

Weight: up to 14kg

Average life span: 15-20 years

Conservation status

Priority Species under the UK Post-2010 Biodiversity Framework.

When to see

January to December

Habitat and Migration Patterns

Brown Trout reside in fast flowing stony and gravely rivers. It is a predatory fish that feeds on insect larvae, small fish and flying insects such as mayfly and damselfly.

How to identify

A medium to large fish, the Brown Trout is golden-brown with a dark back and creamy-yellow belly. Its sides and back display dark and reddish spots with pale borders. Much smaller than the Atlantic Salmon, it can be distinguished from the similar Rainbow Trout by its plain, dark tail fin and by the lack of a purple side-stripe.

Brown Trout Lifecycle

While brown trout reside in fresh water all year round ‘sea trout’ migrate to sea to feed and mature. Some Scottish rivers are home to only brown trout, while others hold populations of sea trout and brown trout.

Spawning occurs between the months of January and march when females who are escorted by males lay their eggs on gravely beds. The eggs are fertilised externally and are buried in gravel. The young fish called fry hatch and feed on their yoke sack before moving to feed on invertebrates.

Egg

Alevin

Fry

Parr

Adult

Brown Trout in your Local River

RiverLife’s Fish in the Classroom programme offers primary aged children the opportunity to watch brown trout from the egg stage to the fry stage of their lifecycle, releasing the fry into local rivers each spring.  Please get in touch for more information or if you would like to get involved with Fish in the Classroom.

The Forth Rivers Trust runs redds identification workshops annually and are always looking for volunteers to get involved with redd counts.  If you’re interested get, in touch.

Have you spotted a brown trout in your local river? We want to hear from you!  If you have photos or stories, please send them to riverlife@forthriverstrust.org.