Brook lamprey · Lampetra planeri

Brook lamprey in the River Granta

Largest measured brook lamprey: 18.6 cm

The largest brook lamprey measured in Environment Agency surveys of the River Granta was 18.6 cm, recorded at Hildersham on 12 May 2022.

Across 30 measured brook lamprey, the median measured length was 12.9 cm.

Surveyors recorded weights for 24 brook lamprey. The median was 0.4 oz (0.012 kg) and the largest recorded weight was 1.1 oz (0.03 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 Granta.

See brook lamprey records across England →

Most recent observation12 May 2022Hildersham · 6 fish

Largest measured brook lamprey: 18.6 cm
Median length: 12.9 cm
Fish measured: 30
Survey locations: 3

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
18.6 cm	12 May 2022	Hildersham	160928
17.2 cm	12 May 2022	Hildersham	160928
16.6 cm	12 May 2022	Hildersham	160928
16.4 cm	12 May 2022	Hildersham	160928
16 cm	16 Mar 2005	Hildersham	84271
15.6 cm	12 May 2022	Hildersham	160928
15.4 cm	8 Apr 2013	Great Shelford	135807
15.1 cm	12 May 2022	Hildersham	160928
14.5 cm	20 Mar 2008	Hildersham	110566
14.2 cm	26 Apr 2016	Hildersham	147962

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
Hildersham	24 Jan 1997	12 May 2022	6
Great Shelford	8 Apr 2013	8 Apr 2013	1
DS Hildersham	16 May 2001	16 May 2001	1

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

1997–2022

Survey records by year

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

197

098

099

000

101

002

003

004

105

006

007

108

009

010

011

012

213

014

015

116

017

018

019

020

021

122

Fish measured by surveyors

Measured length distribution

See how the 30 measured fish were spread across different length ranges.

Smallest: 10.5 cm
Lower quarter: 12 cm
Median: 13 cm
Upper quarter: 15 cm
Largest: 18.6 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 24 brook lamprey. This is a subset of the measured fish and may not represent the whole population.

Lightest: 0.2 oz (0.005 kg)
Lower quarter: 0.4 oz (0.01 kg)
Median: 0.4 oz (0.012 kg)
Upper quarter: 0.5 oz (0.015 kg)
Heaviest: 1.1 oz (0.03 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 Granta

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

3-spined stickleback Brown / sea trout Bullhead Minnow Stone loach Roach

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 →