Bleak · Alburnus alburnus

Bleak in the River Colnebrook

Largest measured bleak: 16.2 cm

The largest bleak measured in Environment Agency surveys of the River Colnebrook was 16.2 cm, recorded at Hythe End on 14 August 2002.

Across 81 measured bleak, the median measured length was 9.9 cm.

Surveyors recorded weights for 7 bleak. The median was 1 oz (0.028 kg) and the largest recorded weight was 1.4 oz (0.04 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 bleak records across England →

Most recent observation3 June 2015Wraysbury · 1 fish

Largest measured bleak: 16.2 cm
Median length: 9.9 cm
Fish measured: 81
Survey locations: 4

Individual EA measurements

Largest measured bleak

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
16.2 cm	14 Aug 2002	Hythe End	72405
15.5 cm	15 May 1986	Iver	115811
15.4 cm	25 Jul 2003	Hythe End	76528
15.3 cm	25 Jul 2003	Hythe End	76528
14.6 cm	15 May 1986	Iver	115811
14.5 cm	15 May 1986	Iver	115811
13.9 cm	15 May 1986	Iver	115811
13.9 cm	15 May 1986	Iver	115811
13.5 cm	14 Aug 2002	Hythe End	72405
13.5 cm	14 Aug 2002	Hythe End	72405

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

Explore the river

Where bleak were found

Each point marks a survey location with at least one bleak 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 bleak
Wraysbury	3 Jun 2015	3 Jun 2015	1
Hythe End	20 Nov 2001	12 Jun 2013	10
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.

1986–2015

Survey records by year

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

186

087

088

089

090

091

092

093

094

095

096

097

098

099

000

101

102

103

104

105

006

107

108

009

210

111

012

113

014

115

Fish measured by surveyors

Measured length distribution

See how the 81 measured fish were spread across different length ranges.

Smallest: 4.9 cm
Lower quarter: 8.3 cm
Median: 9.9 cm
Upper quarter: 11.7 cm
Largest: 16.2 cm

0–99 mm

100–199 mm

Lengths are direct survey measurements rather than anglers’ catches.

Fish weighed by surveyors

Measured weight summary

Recorded weights were available for 7 bleak. This is a subset of the measured fish and may not represent the whole population.

Lightest: 0.5 oz (0.014 kg)
Lower quarter: 0.8 oz (0.023 kg)
Median: 1 oz (0.028 kg)
Upper quarter: 1.2 oz (0.0335 kg)
Heaviest: 1.4 oz (0.04 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 Gudgeon

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 →