RiverFish

Bleak · Alburnus alburnus

Bleak in the River Marlow - Cookham

Largest measured bleak: 14.9 cm

The largest bleak measured in Environment Agency surveys of the River Marlow - Cookham was 14.9 cm, recorded at Marlow - Cookham Upper Main Channel on 6 September 2004.

Across 1,288 measured bleak, the median measured length was 9.3 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 Marlow - Cookham.

See bleak records across England →

Most recent observation27 July 2025Marlow - Cookham Upper Main Channel · 18 fish
Largest measured bleak
14.9 cm
Median length
9.3 cm
Fish measured
1,288
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.

LengthSurvey dateSurvey locationSurvey ID
14.9 cm6 Sept 2004Marlow - Cookham Upper Main Channel82341
14.5 cm6 Sept 2004Marlow - Cookham Upper Main Channel82341
14.3 cm1 Sept 2008Marlow - Cookham Upper Main Channel114247
14.2 cm1 Sept 2008Marlow - Cookham Upper Main Channel114247
14.1 cm6 Sept 2004Marlow - Cookham Upper Main Channel82341
13.7 cm1 Sept 2008Cookham Lock Cut114244
13.7 cm3 Sept 2007Cookham Lock Cut106664
13.6 cm6 Sept 2004Marlow - Cookham Upper Main Channel82341
13.5 cm1 Sept 2008Marlow - Cookham Upper Main Channel114247
13.5 cm1 Sept 2008Cookham Lock Cut114244

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 surveyedFirst recordedLast recordedVisits finding bleak
Marlow - Cookham Upper Main Channel1 Sept 199527 Jul 202525
Cookham Lock Cut3 Sept 20077 Sept 20093
Marlow Weir Pool1 Sept 199531 Aug 20053
Marlow Sewage Treatment Outfall1 Sept 199831 Aug 20053

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

1995–2025

Survey records by year

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

Fish measured by surveyors

Measured length distribution

See how the 1,288 measured fish were spread across different length ranges.

Smallest
1 cm
Lower quarter
8 cm
Median
9.3 cm
Upper quarter
10.9 cm
Largest
14.9 cm

Lengths are direct survey measurements rather than anglers’ catches.

More fish in this river

Explore the River Marlow - Cookham

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

Perch Pike Roach Chub Dace 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 →