European eel · Anguilla anguilla

European eel in the River Monnow

Largest measured european eel: 60 cm

The largest european eel measured in Environment Agency surveys of the River Monnow was 60 cm, recorded at Clodock on 23 August 2013.

Across 39 measured european eel, the median measured length was 37 cm.

Surveyors recorded weights for 8 european eel. The median was 2 oz (0.058 kg) and the largest recorded weight was 4.6 oz (0.13 kg).

RiverFish uses Environment Agency survey measurements rather than rod-and-line angling records. These figures show fish measured during EA surveys of the River Monnow.

See european eel records across England →

Most recent observation5 August 2025Clodock · 3 fish

Largest measured european eel: 60 cm
Median length: 37 cm
Fish measured: 39
Survey locations: 9

Individual EA measurements

Largest measured european eel

The largest individual measurements in this river and species dataset. Equal measurements are retained as separate surveyed fish.

Length	Survey date	Survey location	Survey ID
60 cm	23 Aug 2013	Clodock	138242
60 cm	2 Aug 2010	Llanveynoe	124299
55 cm	9 Aug 2011	Llanveynoe	127390
51 cm	22 Aug 2019	Clodock	155789
50.5 cm	24 Jul 2012	Llanveynoe	132527
50 cm	23 Aug 2013	Clodock	138242
45 cm	2 Aug 2010	Llanveynoe	124299
44 cm	22 Jul 2008	Llanveynoe	115753
43 cm	22 Aug 2019	Clodock	155789
41 cm	22 Aug 2019	Clodock	155789

Lengths are direct survey measurements. RiverFish does not estimate fish weights from length.

Explore the river

Where european eel were found

Each point marks a survey location with at least one european eel 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 surveyed	First recorded	Last recorded	Visits finding european eel
Clodock	11 Jul 1989	5 Aug 2025	9
Llanveynoe	13 Aug 1987	24 Jul 2012	9
W059J	30 Sept 2002	16 Sept 2003	2
W059H	21 Sept 2000	16 Sept 2003	3
W059G	21 Sept 2000	16 Sept 2003	3
W059F	30 Sept 2002	16 Sept 2003	2
W098p	30 Jul 1997	4 Sept 1999	2
W098r	20 Jul 1997	20 Jul 1997	1
W055	11 Jul 1989	22 Aug 1995	5

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

1987–2025

Survey records by year

Each bar shows how many survey visits recorded european eel that year.

187

188

389

290

191

192

293

094

195

096

297

098

299

200

001

402

403

004

005

006

107

208

109

110

111

112

113

014

015

016

017

018

119

020

021

022

023

024

125

Fish measured by surveyors

Measured length distribution

See how the 39 measured fish were spread across different length ranges.

Smallest: 18 cm
Lower quarter: 28.8 cm
Median: 37 cm
Upper quarter: 41 cm
Largest: 60 cm

100–199 mm

200–299 mm

300–399 mm

400–499 mm

500–599 mm

600–699 mm

Lengths are direct survey measurements rather than anglers’ catches.

Fish weighed by surveyors

Measured weight summary

Recorded weights were available for 8 european eel. This is a subset of the measured fish and may not represent the whole population.

Lightest: 0.6 oz (0.018 kg)
Lower quarter: 1.5 oz (0.0435 kg)
Median: 2 oz (0.058 kg)
Upper quarter: 2.6 oz (0.0742 kg)
Heaviest: 4.6 oz (0.13 kg)

These are direct individual weights recorded by Environment Agency surveyors. Combined bulk weights are not included.

More fish in this river

Explore the River Monnow

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

Brown / sea trout Bullhead Stone loach Minnow Grayling

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 →