Gudgeon · Gobio gobio

Gudgeon in the River Colnebrook

Largest measured gudgeon: 15.6 cm

The largest gudgeon measured in Environment Agency surveys of the River Colnebrook was 15.6 cm, recorded at Iver on 15 May 1986.

Across 208 measured gudgeon, the median measured length was 11.1 cm.

Surveyors recorded weights for 100 gudgeon. The median was 0.6 oz (0.016 kg) and the largest recorded weight was 1.9 oz (0.053 kg).

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

See gudgeon records across England →

Most recent observation2 June 2026Wraysbury · 3 fish

Largest measured gudgeon: 15.6 cm
Median length: 11.1 cm
Fish measured: 208
Survey locations: 6

Individual EA measurements

Largest measured gudgeon

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
15.6 cm	15 May 1986	Iver	115811
14.5 cm	4 Jun 2024	Wraysbury	166010
14.3 cm	15 May 1986	Iver	115811
14.2 cm	4 Jun 2009	Thorney Golf Course	117314
14.2 cm	15 May 1986	Iver	115811
14.1 cm	15 May 1986	Iver	115811
14 cm	15 May 1986	Iver	115811
13.8 cm	16 Oct 2001	Thorney Golf Course	73302
13.8 cm	15 May 1986	Iver	115811
13.7 cm	15 May 1986	Iver	115811

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

Explore the river

Where gudgeon were found

Each point marks a survey location with at least one gudgeon 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 gudgeon
Wraysbury	3 Jun 2015	2 Jun 2026	7
Thorney Golf Course	13 May 1986	20 Jun 2023	10
Hythe End	20 Nov 2001	6 Jun 2014	7
Horton Middle Site	23 Apr 2010	23 Apr 2010	1
Horton Downstream site	23 Apr 2010	23 Apr 2010	1
Iver	15 May 1986	15 May 1986	1

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

1986–2026

Survey records by year

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

286

087

088

089

090

091

092

093

094

095

096

097

098

099

000

201

002

003

104

105

106

207

208

209

210

011

012

113

114

215

016

117

218

119

020

021

022

123

124

125

126

Fish measured by surveyors

Measured length distribution

See how the 208 measured fish were spread across different length ranges.

Smallest: 1 cm
Lower quarter: 9.8 cm
Median: 11.1 cm
Upper quarter: 12.2 cm
Largest: 15.6 cm

0–99 mm

100–199 mm

152

Lengths are direct survey measurements rather than anglers’ catches.

Fish weighed by surveyors

Measured weight summary

Recorded weights were available for 100 gudgeon. This is a subset of the measured fish and may not represent the whole population.

Lightest: 0.1 oz (0.0021 kg)
Lower quarter: 0.5 oz (0.0128 kg)
Median: 0.6 oz (0.016 kg)
Upper quarter: 0.8 oz (0.023 kg)
Heaviest: 1.9 oz (0.053 kg)

These are direct individual weights recorded by Environment Agency surveyors. Combined bulk weights are not included.

More fish in this river

Explore the River Colnebrook

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

European eel Perch Roach Chub Pike Minnow

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 →