Gudgeon · Gobio gobio

Gudgeon in England's Rivers

The largest recorded measurement is 50 cm (19.7 in), from Castle Mill, Hanley Castle in Pool Brook on 17 June 1992.

Median length: 9.5 cm (3.7 in)
Fish measured: 365,756
Named waterways: 962
Latest observation: 23 Jul 2026

Direct individual measurements

Largest gudgeon 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	Pool BrookMidlands	50 cm (19.7 in)	30 cm (11.8 in)	11	17 Jun 1992Castle Mill, Hanley Castle
2	River AireYorkshire and North East	42.2 cm (16.6 in)	8.7 cm (3.4 in)	2,574	21 Aug 2002Thwaite Weir
3	River UreYorkshire and North East	34.9 cm (13.7 in)	7.6 cm (3 in)	2,282	18 Jul 2002Aldwark Bridge (Boom boat)
4	River HolbeckYorkshire and North East	32.9 cm (13 in)	13.2 cm (5.2 in)	4	26 Sept 2001Holbeck, South of East Ness DERBT91
5	Cod BeckYorkshire and North East	29.7 cm (11.7 in)	11.2 cm (4.4 in)	18	25 Jul 2005Cod Beck at Dalton
6	River CamMidlands	25 cm (9.8 in)	10.5 cm (4.1 in)	31	8 Jun 1989u/s Pumping Station
7	River StourAnglian	24.6 cm (9.7 in)	10.1 cm (4 in)	15,716	9 Oct 1991Kedington Radial Gate
8	River GlazeNorth West	24 cm (9.4 in)	10.5 cm (4.1 in)	337	19 May 2008Glgl25
9	River BollinNorth West	22.9 cm (9 in)	11 cm (4.3 in)	998	3 Aug 2009Bobo10
10	River ArrowMidlands	22.8 cm (9 in)	11.2 cm (4.4 in)	2,660	15 Jul 2004Studley

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

365,756 fish measured

Measured gudgeon lengths

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

0–19 mm

809

20–39 mm

17224

40–59 mm

26664

60–79 mm

55305

80–99 mm

108998

100–119 mm

100325

120–139 mm

44979

140–159 mm

10365

160–179 mm

946

180–199 mm

200–219 mm

220–239 mm

240–259 mm

260–279 mm

280–299 mm

300–319 mm

320–339 mm

340–359 mm

360–379 mm

400–419 mm

420–439 mm

500–519 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 gudgeon observations

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

Date	River or waterway	Survey location	Fish recorded
23 Jul 2026	River Weaver	Wewe25	4
23 Jul 2026	River Lee	Amwell Loop	16
22 Jul 2026	River Darent	Twitton Brook	92
21 Jul 2026	River Medway	Sovereign Way Tonbridge	12
21 Jul 2026	River Colne	Uxbridge	1
16 Jul 2026	River Colne	Watford M1 link road	23
15 Jul 2026	Saredon Brook	US Canal Feeder	3
15 Jul 2026	River Medway	Tovil	1
7 Jul 2026	River Lee	Fishers Green	2
2 Jul 2026	Chad Brook (Main Reaches)	Broad Meadows	12

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

17,071 positive survey visits

Survey distribution

EA surveys recorded gudgeon at 4,511 locations across 962 named waterways represented on RiverFish.

Region	Waterways	Locations	Survey visits	Latest record
Anglian	263	1,478	6,247	2 Jul 2026
South East	261	1,132	4,591	23 Jul 2026
Midlands	182	869	2,778	15 Jul 2026
South West	98	316	883	17 Jun 2026
North West	84	305	727	23 Jul 2026
Yorkshire and North East	74	411	1,845	2 Jul 2026

527 detailed pages

Gudgeon by river

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

Anglian 167 pages

Midlands 84 pages

North West 33 pages

South East 156 pages

South West 51 pages

Yorkshire and North East 36 pages

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 gudgeon.

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 →