Brook lamprey · Lampetra planeri

Brook lamprey in the River Nar

Largest measured brook lamprey: 17 cm

The largest brook lamprey measured in Environment Agency surveys of the River Nar was 17 cm, recorded at Wormegay High Bridge on 20 April 2010.

Across 34 measured brook lamprey, the median measured length was 13.1 cm.

Surveyors recorded weights for 31 brook lamprey. The median was 0.1 oz (0.004 kg) and the largest recorded weight was 0.4 oz (0.01 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 Nar.

See brook lamprey records across England →

Most recent observation1 April 2025DS Narborough Mill · 1 fish

Largest measured brook lamprey: 17 cm
Median length: 13.1 cm
Fish measured: 34
Survey locations: 7

Individual EA measurements

Largest measured brook lamprey

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
17 cm	20 Apr 2010	Wormegay High Bridge	121401
15 cm	20 Apr 2010	Wormegay High Bridge	121401
15 cm	20 Apr 2010	Wormegay High Bridge	121401
15 cm	25 Mar 2004	Setchey	79523
14.4 cm	1 Apr 2025	DS Narborough Mill	176113
14.4 cm	12 Mar 2015	Wormegay High Bridge	144457
14.1 cm	1 Apr 2015	White House Farm Kings Lynn	144497
14 cm	20 Apr 2010	Wormegay High Bridge	121401
14 cm	20 Apr 2010	Wormegay High Bridge	121401
13.7 cm	1 Apr 2015	White House Farm Kings Lynn	144497

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

Explore the river

Where brook lamprey were found

Each point marks a survey location with at least one brook lamprey 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 brook lamprey
DS Narborough Mill	1 Apr 2025	1 Apr 2025	1
Narford Hall Estate	9 Apr 2019	9 Apr 2019	1
White House Farm Kings Lynn	1 Apr 2015	1 Apr 2015	1
Saddlebow	26 Mar 2015	26 Mar 2015	1
Setchey	25 Mar 2004	17 Mar 2015	2
Wormegay High Bridge	20 Apr 2010	12 Mar 2015	2
Abbey Farm	19 Mar 2004	19 Mar 2004	1

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

2004–2025

Survey records by year

Each bar shows how many survey visits recorded brook lamprey that year.

204

005

006

007

008

009

110

011

012

013

014

415

016

017

018

119

020

021

022

023

024

125

Fish measured by surveyors

Measured length distribution

See how the 34 measured fish were spread across different length ranges.

Smallest: 11 cm
Lower quarter: 12.3 cm
Median: 13.1 cm
Upper quarter: 13.9 cm
Largest: 17 cm

100–199 mm

Lengths are direct survey measurements rather than anglers’ catches.

Fish weighed by surveyors

Measured weight summary

Recorded weights were available for 31 brook lamprey. This is a subset of the measured fish and may not represent the whole population.

Lightest: 0.1 oz (0.003 kg)
Lower quarter: 0.1 oz (0.003 kg)
Median: 0.1 oz (0.004 kg)
Upper quarter: 0.2 oz (0.0055 kg)
Heaviest: 0.4 oz (0.01 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 Nar

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

European eel Bullhead 3-spined stickleback Brown / sea trout Pike Dace

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 →