Brook lamprey · Lampetra planeri

Brook lamprey in the River Menalhyl

Largest measured brook lamprey: 13.1 cm

The largest brook lamprey measured in Environment Agency surveys of the River Menalhyl was 13.1 cm, recorded at Tolcarne on 20 June 2018.

Across 6 measured brook lamprey, the median measured length was 10.5 cm.

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

See brook lamprey records across England →

Most recent observation20 June 2018Gluvian · 2 fish

Largest measured brook lamprey: 13.1 cm
Median length: 10.5 cm
Fish measured: 6
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
13.1 cm	20 Jun 2018	Tolcarne	152985
12 cm	24 May 2012	Redbarn	131282
10.6 cm	20 Jun 2018	Gluvian	152987
10.4 cm	20 Jun 2018	Gluvian	152987
10 cm	20 Jun 2018	Tolcarne	152985
9.5 cm	24 May 2012	Redbarn	131282

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
Tolcarne	20 Jun 2018	20 Jun 2018	1
Gluvian	20 Jun 2018	20 Jun 2018	1
Redbarn	24 May 2012	24 May 2012	1

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

2012–2018

Survey records by year

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

112

013

014

015

016

017

218

Fish measured by surveyors

Measured length distribution

See how the 6 measured fish were spread across different length ranges.

Smallest: 9.5 cm
Lower quarter: 10.1 cm
Median: 10.5 cm
Upper quarter: 11.7 cm
Largest: 13.1 cm

0–99 mm

100–199 mm

Lengths are direct survey measurements rather than anglers’ catches.

More fish in this river

Explore the River Menalhyl

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

Brown / sea trout European eel Flounder 3-spined stickleback Minnow

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 →