Brook lamprey · Lampetra planeri

Brook lamprey in the Main Horner Water

Largest measured brook lamprey: 13.5 cm

The largest brook lamprey measured in Environment Agency surveys of the Main Horner Water was 13.5 cm, recorded at Bossington (WFD) on 23 April 2013.

Across 11 measured brook lamprey, the median measured length was 12.5 cm.

Surveyors recorded weights for 2 brook lamprey. The median was 0.1 oz (0.0035 kg) and the largest recorded weight was 0.1 oz (0.004 kg).

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

See brook lamprey records across England →

Most recent observation23 April 2013Bossington (WFD) · 4 fish

Largest measured brook lamprey: 13.5 cm
Median length: 12.5 cm
Fish measured: 11
Survey locations: 1

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
13.5 cm	23 Apr 2013	Bossington (WFD)	135895
13.5 cm	14 May 2008	Bossington (WFD)	111437
13 cm	12 Apr 2012	Bossington (WFD)	131097
13 cm	12 Apr 2012	Bossington (WFD)	131097
13 cm	5 Apr 2006	Bossington (WFD)	90790
12.5 cm	12 Apr 2012	Bossington (WFD)	131097
12 cm	27 Apr 2007	Bossington (WFD)	105264
11.5 cm	23 Apr 2013	Bossington (WFD)	135895
11 cm	12 Apr 2012	Bossington (WFD)	131097
10.5 cm	23 Apr 2013	Bossington (WFD)	135895

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
Bossington (WFD)	5 Apr 2006	23 Apr 2013	5

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

2006–2013

Survey records by year

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

106

107

108

009

010

011

112

113

Fish measured by surveyors

Measured length distribution

See how the 11 measured fish were spread across different length ranges.

Smallest: 10 cm
Lower quarter: 11.3 cm
Median: 12.5 cm
Upper quarter: 13 cm
Largest: 13.5 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 2 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 (0.0032 kg)
Median: 0.1 oz (0.0035 kg)
Upper quarter: 0.1 oz (0.0038 kg)
Heaviest: 0.1 oz (0.004 kg)

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

More fish in this river

Explore the Main Horner Water

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

Brown / sea trout European eel Bullhead

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 →