RiverFish

Bleak · Alburnus alburnus

Bleak in the River Cookham - Boulters

Largest measured bleak: 14.5 cm

The largest bleak measured in Environment Agency surveys of the River Cookham - Boulters was 14.5 cm, recorded at Odney Weir Stream, Cookham. on 7 September 2004.

Across 1,685 measured bleak, the median measured length was 7.8 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 Cookham - Boulters.

See bleak records across England →

Most recent observation27 July 2025Cliveden Island · 73 fish
Largest measured bleak
14.5 cm
Median length
7.8 cm
Fish measured
1,685
Survey locations
3

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
14.5 cm7 Sept 2004Odney Weir Stream, Cookham.82531
13.9 cm2 Sept 2013Cliveden Island138869
13.8 cm5 Sept 2011Odney Weir Stream, Cookham.128097
13.6 cm5 Sept 2016Cliveden Island149245
13.5 cm7 Sept 2004Odney Weir Stream, Cookham.82531
13.3 cm18 Jul 2024Cliveden Island165850
13.3 cm1 Sept 2005Cliveden Island86178
13.1 cm10 Sept 2002Cliveden Island69061
13 cm5 Sept 2016Cliveden Island149245
12.9 cm28 Jul 2023Cliveden Island163987

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
Cliveden Island1 Sept 199827 Jul 202525
Odney Weir Stream, Cookham.1 Sept 20002 Sept 201312
Hedsor Weir Stream Cookham to Boulters1 Sept 20051 Sept 20051

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

1998–2025

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 1,685 measured fish were spread across different length ranges.

Smallest
3.2 cm
Lower quarter
6.9 cm
Median
7.8 cm
Upper quarter
9.5 cm
Largest
14.5 cm

Lengths are direct survey measurements rather than anglers’ catches.

More fish in this river

Explore the River Cookham - Boulters

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

Roach Perch Pike European eel Dace Chub

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 →