RiverFish

Brook lamprey · Lampetra planeri

Brook lamprey in the River Main Penpont

Largest measured brook lamprey: 14.5 cm

The largest brook lamprey measured in Environment Agency surveys of the River Main Penpont was 14.5 cm, recorded at Trerithick on 15 June 2011.

Across 133 measured brook lamprey, the median measured length was 11 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 Main Penpont.

See brook lamprey records across England →

Most recent observation2 July 2025Trerithick · 8 fish
Largest measured brook lamprey
14.5 cm
Median length
11 cm
Fish measured
133
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
14.5 cm15 Jun 2011Trerithick126787
13.8 cm15 Jun 2011Trerithick126787
13.7 cm20 Jun 2013Trerithick136755
13.5 cm23 Aug 2021Trekennick160444
13.5 cm23 Jun 2021Trerithick160450
13.5 cm10 Jul 2019Trerithick155461
13.4 cm6 Jul 2017Trerithick151253
13.1 cm20 Jun 2013Trerithick136755
13.1 cm11 Sept 2012Trekennick133463
13.1 cm15 Jun 2011Trerithick126787

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
Trerithick14 Jul 20082 Jul 202511
Trekennick8 Jul 200923 Aug 20214
Bowithick24 Jun 200922 Jun 20212

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

2008–2025

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 133 measured fish were spread across different length ranges.

Smallest
5 cm
Lower quarter
9.4 cm
Median
11 cm
Upper quarter
12 cm
Largest
14.5 cm

Lengths are direct survey measurements rather than anglers’ catches.

More fish in this river

Explore the River Main Penpont

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

Brown / sea trout Atlantic salmon Bullhead European eel Minnow 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 →