RiverFish

Brown / sea trout · Salmo trutta

Brown / sea trout in the River Box (Main Reaches)

Largest measured brown / sea trout: 44.6 cm

The largest brown / sea trout measured in Environment Agency surveys of the River Box (Main Reaches) was 44.6 cm, recorded at Stour Confluence on 6 June 2012.

Across 3,065 measured brown / sea trout, the median measured length was 17.3 cm.

RiverFish uses Environment Agency survey measurements rather than rod-and-line angling records. These figures show fish measured during EA surveys of the River Box (Main Reaches).

See brown / sea trout records across England →

Most recent observation22 May 2026Stour Confluence · 3 fish
Largest measured brown / sea trout
44.6 cm
Median length
17.3 cm
Fish measured
3,065
Survey locations
7

Individual EA measurements

Largest measured brown / sea trout

The largest individual measurements in this river and species dataset. Equal measurements are retained as separate surveyed fish.

LengthSurvey dateSurvey locationSurvey ID
44.6 cm6 Jun 2012Stour Confluence132348
43.4 cm31 May 2018Thorington Mill152769
42.8 cm21 May 2026Scotland Street181411
39.6 cm31 May 2018Thorington Mill152769
38.1 cm13 Apr 1988Polstead Mill13782
37.8 cm23 Apr 2014Stour Confluence140716
37.1 cm16 May 2006Thorington Mill100293
37 cm18 May 2015Stone Street144739
37 cm27 Mar 1985Polstead Mill13776
36.4 cm15 May 2006Stour Confluence100298

Lengths are direct survey measurements. RiverFish does not estimate fish weights from length.

Explore the river

Where brown / sea trout were found

Each point marks a survey location with at least one brown / sea trout record.

Choose a point on the map to see what was recorded there.

Map points are approximate and don’t show fishing access. Check local permissions before visiting.

Place surveyedFirst recordedLast recordedVisits finding brown / sea trout
Stour Confluence11 Apr 198822 May 202611
Scotland Street26 Mar 198521 May 202616
Polstead Mill27 Mar 198511 Jun 202411
Stone Street29 Mar 19857 Jun 202412
Peyton Hall Farm25 Apr 19916 Jun 20249
Thorington Mill25 Mar 19858 May 20249
Polstead Ford28 Mar 19857 May 202411

Choose a point or table row to see the location. More survey visits can mean more records, but not necessarily more fish.

1985–2026

Survey records by year

Each bar shows how many survey visits recorded brown / sea trout that year.

Fish measured by surveyors

Measured length distribution

See how the 3,065 measured fish were spread across different length ranges.

Smallest
5.2 cm
Lower quarter
14.6 cm
Median
17.3 cm
Upper quarter
23.1 cm
Largest
44.6 cm

Lengths are direct survey measurements rather than anglers’ catches.

More fish in this river

Explore the River Box (Main Reaches)

Compare other species with enough survey and measurement data for a detailed page.

European eel Stone loach Dace Roach Chub 3-spined stickleback

Before you fish

Good to know

These are past survey records, so the fish present today may be different. Map points are approximate—check local access, permissions and fishing rules before visiting.

Learn how RiverFish uses the data →