RiverFish

Flounder · Platichthys flesus

Flounder in the River Derwent (Yorkshire)

Largest measured flounder: 40.5 cm

The largest flounder measured in Environment Agency surveys of the River Derwent (Yorkshire) was 40.5 cm, recorded at Stamford Bridge DERCORS10 on 2 September 2003.

Across 94 measured flounder, the median measured length was 19.8 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 Derwent (Yorkshire).

See flounder records across England →

Most recent observation21 July 2015Sutton Upon Derwent DERCORS18 · 1 fish
Largest measured flounder
40.5 cm
Median length
19.8 cm
Fish measured
94
Survey locations
5

Individual EA measurements

Largest measured flounder

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

LengthSurvey dateSurvey locationSurvey ID
40.5 cm2 Sept 2003Stamford Bridge DERCORS1078344
39.8 cm17 Sept 2009Stamford Bridge DERCORS10119811
37.7 cm17 Sept 2009Stamford Bridge DERCORS10119811
37.1 cm6 Sept 2002Stamford Bridge DERCORS1072277
37 cm6 Sept 2002Stamford Bridge DERCORS1072277
35.7 cm6 Sept 2002Stamford Bridge DERCORS1072277
32.7 cm14 Sept 2001Sutton Upon Derwent DERCORS1824183
32.2 cm16 Sept 2002Barmby on the Marsh DERCORS2172295
31.1 cm9 Sept 2002Sutton Upon Derwent DERCORS1872285
30.9 cm26 Sept 1997Sutton Upon Derwent DERCORS18109884

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

Explore the river

Where flounder were found

Each point marks a survey location with at least one flounder 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 flounder
Sutton Upon Derwent DERCORS1826 Sept 199721 Jul 20159
Stamford Bridge DERCORS1013 Sept 200117 Sept 20096
Wheldrake Ings DERCORS1922 Sept 200522 Sept 20051
Barmby on the Marsh DERCORS2123 Sept 199711 Sept 20035
Breighton DERCORS2016 Sept 200210 Sept 20032

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

1997–2015

Survey records by year

Each bar shows how many survey visits recorded flounder that year.

Fish measured by surveyors

Measured length distribution

See how the 94 measured fish were spread across different length ranges.

Smallest
4 cm
Lower quarter
14.9 cm
Median
19.8 cm
Upper quarter
25.9 cm
Largest
40.5 cm

Lengths are direct survey measurements rather than anglers’ catches.

More fish in this river

Explore the River Derwent (Yorkshire)

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

Minnow Bullhead Stone loach Dace European eel 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 →