RiverFish

Brook lamprey · Lampetra planeri

Brook lamprey in the River Blackwater

Largest measured brook lamprey: 13.4 cm

The largest brook lamprey measured in Environment Agency surveys of the River Blackwater was 13.4 cm, recorded at Landford on 5 August 2005.

Across 16 measured brook lamprey, the median measured length was 11.2 cm.

Surveyors recorded weights for 5 brook lamprey. The median was 0.1 oz (0.002 kg) and the largest recorded weight was 0.1 oz (0.003 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 Blackwater.

See brook lamprey records across England →

Most recent observation18 September 2025Landford · 1 fish
Largest measured brook lamprey
13.4 cm
Median length
11.2 cm
Fish measured
16
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.

LengthSurvey dateSurvey locationSurvey ID
13.4 cm5 Aug 2005Landford86383
13.2 cm13 Sept 2022Landford161531
12.4 cm5 Aug 2005Landford86383
12 cm13 Sept 2022Landford161531
12 cm13 Sept 2022Landford161531
11.6 cm23 Sept 2019Landford155453
11.6 cm3 Sept 2018Landford153650
11.4 cm5 Aug 2005Landford86383
10.9 cm3 Sept 2018Landford153650
10.5 cm13 Sept 2022Landford161531

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 surveyedFirst recordedLast recordedVisits finding brook lamprey
Landford4 Sept 200218 Sept 20259
Broadlands Fishery20 Sept 201119 Sept 20246
Upper Whinwhistle20 Sept 201120 Sept 20111

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

2002–2025

Survey records by year

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

Fish measured by surveyors

Measured length distribution

See how the 16 measured fish were spread across different length ranges.

Smallest
7 cm
Lower quarter
10.2 cm
Median
11.2 cm
Upper quarter
12 cm
Largest
13.4 cm

Lengths are direct survey measurements rather than anglers’ catches.

Fish weighed by surveyors

Measured weight summary

Recorded weights were available for 5 brook lamprey. This is a subset of the measured fish and may not represent the whole population.

Lightest
0.1 oz (0.002 kg)
Lower quarter
0.1 oz (0.002 kg)
Median
0.1 oz (0.002 kg)
Upper quarter
0.1 oz (0.003 kg)
Heaviest
0.1 oz (0.003 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 Blackwater

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

Roach Bullhead European eel Dace Brown / sea trout Stone loach

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 →