Bleak · Alburnus alburnus

Bleak in England's Rivers

The largest recorded measurement is 103.6 cm (40.8 in), from Naburn Weir (seine net) in River Ouse on 8 August 1997.

Median length: 8.9 cm (3.5 in)
Fish measured: 199,852
Named waterways: 294
Latest observation: 21 Jul 2026

Direct individual measurements

Largest bleak by waterway

Ranked by the largest individual measured in EA surveys. The sample size shows how many valid length measurements underpin each waterway's figures.

Rank	River or waterway	Largest	Median	Measured	Measured at
1	River OuseYorkshire and North East	103.6 cm (40.8 in)	7.9 cm (3.1 in)	6,458	8 Aug 1997Naburn Weir (seine net)
2	River UreYorkshire and North East	99.9 cm (39.3 in)	6.5 cm (2.6 in)	1,162	17 Jul 2003Hewick Bridge (Boom boat)
3	River DonYorkshire and North East	23.4 cm (9.2 in)	10.1 cm (4 in)	1,240	25 Jul 2012Kilnhurst Bridge
4	River EdenSouth East	22.4 cm (8.8 in)	8.1 cm (3.2 in)	2,049	9 Sept 2004Delaware Farm
5	River Warwickshire AvonMidlands	21 cm (8.3 in)	8.9 cm (3.5 in)	171	6 May 1996Barton
6	River Romney - Old WindsorSouth East	20.7 cm (8.1 in)	8.9 cm (3.5 in)	2,652	12 Sept 2002Romney Main
7	Cowbridge DrainAnglian	20.3 cm (8 in)	13.2 cm (5.2 in)	54	20 Jul 2011Kelsey Bridge
8	River DearneYorkshire and North East	19.9 cm (7.8 in)	2.9 cm (1.1 in)	901	30 Jun 2008meanders u/s Pastures Bridge
9	Old River LeaSouth East	19.8 cm (7.8 in)	10 cm (3.9 in)	1,618	9 May 2008Cornmill Meadows 3 (Mile Nursery)
10	River ThamesSouth East	19.6 cm (7.7 in)	8.5 cm (3.3 in)	59,485	5 Jul 1996Days - Benson (Middle)

Equal maximum lengths are ordered by sample size. Measurements are shown as recorded and are not converted into estimated weights.

199,852 fish measured

Measured bleak lengths

The median divides the measured sample in half. This distribution describes surveyed fish, not every bleak living in England.

0–19 mm

545

20–39 mm

12641

40–59 mm

17763

60–79 mm

39769

80–99 mm

63792

100–119 mm

46773

120–139 mm

15709

140–159 mm

2514

160–179 mm

297

180–199 mm

200–219 mm

220–239 mm

980–999 mm

1020–1039 mm

Only positive individual lengths that pass RiverFish's general measurement checks are included. Each bar covers a 20 mm range.

Latest EA evidence

Latest bleak observations

The ten most recent survey visits that recorded bleak in named waterways.

Date	River or waterway	Survey location	Fish recorded
21 Jul 2026	River Medway	Sovereign Way Tonbridge	72
16 Jul 2026	River Medway	Golden Green	43
15 Jul 2026	River Medway	Teston	44
15 Jul 2026	River Medway	Tovil	1
14 Jul 2026	River Stour	Tendring Hall	14
3 Jul 2026	River Stour	Higham Hall	7
22 Jun 2026	River Ouse	Naburn Weir (single anode)	42
18 Jun 2026	River Medway	Yalding Leas	259
18 Jun 2026	River Dearne	meanders u/s Pastures Bridge	8
10 Jun 2026	Counter Drain	Welney	2

A survey record confirms bleak at that place and time. It does not show present-day abundance or fishing access.

5,810 positive survey visits

Survey distribution

EA surveys recorded bleak at 1,367 locations across 294 named waterways represented on RiverFish.

Region	Waterways	Locations	Survey visits	Latest record
South East	114	512	2,745	21 Jul 2026
Anglian	109	543	1,800	14 Jul 2026
Midlands	48	214	607	9 Jun 2026
Yorkshire and North East	13	80	579	22 Jun 2026
South West	7	15	76	19 Sept 2024
North West	3	3	3	12 May 2026

174 detailed pages

Bleak by river

Open any river-specific page for its measured lengths, largest surveyed individuals, locations and observation history.

Anglian 69 pages

Midlands 20 pages

South East 71 pages

South West 4 pages

Bristol Avon main river7 locations · latest 2024 Main Avon Sites1 locations · latest 2011 Main river sites9 locations · latest 2018 Main River Tone3 locations · latest 2024

Yorkshire and North East 10 pages

River Aire4 locations · latest 2024 River Calder1 locations · latest 2024 River Dearne3 locations · latest 2026 River Derwent (Yorkshire)9 locations · latest 2024 River Don8 locations · latest 2025 River Nidd7 locations · latest 2025 River Ouse19 locations · latest 2026 River Swale5 locations · latest 2025 River Ure15 locations · latest 2025 River Wharfe5 locations · latest 2024

How to read this page

Survey measurements, not angling records

Environment Agency surveys are designed to monitor fish populations. Their largest measurement is not equivalent to a verified rod-and-line record, and the survey sample does not include every river or every bleak.

Waterway groups with administrative or mixed-river labels are excluded from the headline national totals and rankings. Their eligible river-specific pages remain available in the directory so no published destination is hidden.

The fish records use the Environment Agency source snapshot dated 10 August 2026.

How RiverFish handles the data →