RiverFish

Bleak · Alburnus alburnus

Bleak in the River Thames

Largest measured bleak: 19.6 cm

The largest bleak measured in Environment Agency surveys of the River Thames was 19.6 cm, recorded at Days - Benson (Middle) on 5 July 1996.

Across 59,485 measured bleak, the median measured length was 8.5 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 Thames.

See bleak records across England →

Most recent observation16 October 2025Hannington Bridge · 38 fish
Largest measured bleak
19.6 cm
Median length
8.5 cm
Fish measured
59,485
Survey locations
79

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
19.6 cm5 Jul 1996Days - Benson (Middle)113209
19.2 cm9 Jul 1998Days - Benson (Margin)113047
19 cm7 Jun 2001Rushey to Shifford79302
18.5 cm23 Sept 1993Clifton Hampden - Days (Middle)116359
17.3 cm6 Jul 2003Clifton Hampden - Days (Margin)76439
17.2 cm25 Oct 2007Eynsham- kings108419
17.2 cm2 Jul 1996Abingdon - Culham (Middle)106605
17.1 cm1 Oct 2015Northmoor- Pinkhill146944
16.9 cm9 Oct 2007Castle Eaton108428
16.7 cm22 Jul 2019Culham - Clifton Hampden (Margin)155305

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
Hannington Bridge29 Aug 200316 Oct 202512
Castle Eaton22 Aug 200316 Oct 202513
Cricklade30 Jul 200314 Oct 202510
Godstow to Osney19 Jun 200126 Sept 202519
Eynsham- kings14 Jun 200126 Sept 202517
Northmoor- Pinkhill12 Jun 200125 Sept 202518
Rushey to Shifford7 Jun 200124 Sept 202520
Buscot to Grafton5 Jun 200123 Sept 202518
Roundhouse to St Johns(margins)26 Jun 200222 Sept 202519
Hambleden - Hurley (margin)24 Jul 200125 Jul 202516
Hambleden - Hurley (Weirpool)23 Jul 200325 Jul 202512
Shiplake-marsh - (Margin)24 Jul 200224 Jul 202516
Shiplake - Marsh (Weirpool)22 Jul 200324 Jul 202514
Caversham-sonning - (Margin)17 Jul 200123 Jul 202516
Caversham (Weirpool)17 Jul 200323 Jul 202514
Whitchurch to Mapledurham (Margin)12 Jul 200122 Jul 202517
Whitchurch (Weirpool)12 Jul 200122 Jul 202516
Cleeve-Goring - (Margin)3 Jul 200121 Jul 202517
Cleeve - Goring (Weirpool)15 Jul 200321 Jul 20257
Days weirpool18 Jul 200820 Jul 202515
Days - Benson (Margin)24 Sept 199320 Jul 202529
Clifton Weir Stream17 Jul 200819 Jul 202515
Clifton Hampden - Days (Margin)23 Sept 199319 Jul 202529
Culham Weirpool15 Jul 200818 Jul 202514
Culham - Clifton Hampden (Margin)22 Sept 199318 Jul 202529
Abingdon Weirpool8 Jul 200915 Jul 202514
Abingdon - Culham (Margin)21 Sept 199315 Jul 202530
Sandford Weir stream7 Jul 200910 Jul 20259
Sandford - Abingdon - (Margin)20 Sept 199310 Jul 202530
Iffley - Sandford (Margin)11 Jul 19999 Jul 202523
Godstow Weirpool26 Oct 201129 Sept 202310
Shifford Fish Pass2 Nov 20222 Nov 20221
Water eaton2 Oct 200218 Oct 20229
Port Meadow (Day/Night)22 Jun 201816 Jul 20196
Canal confluence to Marina22 Jun 201815 Jul 20195
Days weirpool (daytime)11 Jul 201811 Jul 20181
Days - Benson (daytime)11 Jul 201811 Jul 20181
Sutton Pools7 Oct 20147 Oct 20141
Rushey bypass channel18 Sept 201418 Sept 20141
Days Lock5 Jul 20145 Jul 20141
Shifford Lock Cut18 Oct 201318 Oct 20131
Radcot - Rushey17 Oct 201317 Oct 20131
St John's Lock Cut16 Oct 201316 Oct 20131
Buscot weir pool24 Sept 200316 Oct 20137
Radcot Fish Pass25 Sept 201325 Sept 20131
Sonning - shiplake (Margin)17 Jul 200912 Jul 20135
Goring weir pool20 Jul 20089 Jul 20136
Goring to Whitchurch (Margin)20 Jul 20089 Jul 20136
Benson Weirpool26 Jul 20127 Jul 20132
Sonning Weirstream22 Jul 201031 Jul 20122
Rushey Weir Pool12 Oct 200425 Oct 20117
Sonning Weir17 Jul 200923 Jul 20112
Eynsham weirpool1 Oct 20038 Oct 20104
Northmoor Wier pool26 Sept 200323 Oct 20084
Marsh - Hambleden (Margin)24 Jul 200824 Jul 20081
Loddon - Confluence to St Pats Stream24 Jul 200824 Jul 20081
Mapledurham weirpool22 Jul 200822 Jul 20081
Mapledurham Mill Channel22 Jul 200822 Jul 20081
Mapledurham - Caversham (Margin)22 Jul 200822 Jul 20081
Shifford to Newbridge - Windrush Confluence23 Oct 200723 Oct 20071
Newbridge - Windrush Confluence - to Northmoor23 Oct 200723 Oct 20071
Port Meadow1 Sept 20071 Sept 20071
Donnington Bridge1 Sept 20071 Sept 20071
St Patricks stream16 Nov 200616 Nov 20061
Eynsham Weir Stream17 Mar 200617 Mar 20061
Godstow weirstream1 Oct 200326 Sept 20052
Days - Benson (Middle)24 Sept 19939 Jul 200512
Clifton Hampden - Days (Middle)23 Sept 19938 Jul 200512
Culham - Clifton Hampden (Middle)22 Sept 19937 Jul 200512
Abingdon - Culham (Middle)21 Sept 19936 Jul 200512
Sandford - Abingdon - Middle20 Sept 19935 Jul 200512
Iffley - Sandford (Middle)11 Jul 19994 Jul 20056
400yds d/s hannington B-small trib on RB24 Sept 200224 Sept 20021
Hambleden - Hurley (middle)24 Jul 200125 Jul 20022
Shiplake-Marsh - (Mid-River)24 Jul 200224 Jul 20021
Caversham-sonning - (Mid River)17 Jul 200123 Jul 20022
Whitchurch - Mapledurham (Middle)12 Jul 200118 Jul 20022
Cleeve-Goring - (Mid River)3 Jul 200117 Jul 20022
Roundhouse to St Johns(mid-river)26 Jun 200226 Jun 20021

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

1993–2025

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 59,485 measured fish were spread across different length ranges.

Smallest
1.6 cm
Lower quarter
6.9 cm
Median
8.5 cm
Upper quarter
9.9 cm
Largest
19.6 cm

Lengths are direct survey measurements rather than anglers’ catches.

More fish in this river

Explore the River Thames

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

Roach Pike Chub Perch 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 →