Flounder · Platichthys flesus

Flounder in the River Heigham Sound

Largest measured flounder: 20.5 cm

The largest flounder measured in Environment Agency surveys of the River Heigham Sound was 20.5 cm, recorded at 58 on 27 September 1989.

Across 639 measured flounder, the median measured length was 6.2 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 Heigham Sound.

See flounder records across England →

Most recent observation18 September 199859 · 4 fish

Largest measured flounder: 20.5 cm
Median length: 6.2 cm
Fish measured: 639
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.

Length	Survey date	Survey location	Survey ID
20.5 cm	27 Sept 1989	58	16924
18.1 cm	23 Sept 1986	57	16916
18 cm	27 Sept 1989	58	16924
17.3 cm	27 Sept 1989	58	16924
17 cm	30 Sept 1986	60	16919
16.9 cm	23 Sept 1986	57	16916
16.3 cm	27 Sept 1989	58	16924
16.2 cm	29 Sept 1989	57	16921
16 cm	27 Sept 1989	58	16924
15.8 cm	29 Sept 1986	59	16918

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 surveyed	First recorded	Last recorded	Visits finding flounder
59	29 Sept 1986	18 Sept 1998	2
61	30 Sept 1986	12 Aug 1998	4
60	30 Sept 1986	10 Aug 1998	2
57	23 Sept 1986	7 Aug 1998	3
58	29 Sept 1986	5 Aug 1998	4

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

1986–1998

Survey records by year

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

586

087

088

389

090

091

092

293

094

095

096

097

598

Fish measured by surveyors

Measured length distribution

See how the 639 measured fish were spread across different length ranges.

Smallest: 3 cm
Lower quarter: 5.1 cm
Median: 6.2 cm
Upper quarter: 7.3 cm
Largest: 20.5 cm

0–99 mm

606

100–199 mm

200–299 mm

Lengths are direct survey measurements rather than anglers’ catches.

More fish in this river

Explore the River Heigham Sound

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

Roach Perch Common bream Smelt Common goby

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 →