RiverFish

River lamprey · Lampetra fluviatilis

River lamprey in the River Riding Mill

Largest measured river lamprey: 32 cm

The largest river lamprey measured in Environment Agency surveys of the River Riding Mill was 32 cm, recorded at Riding Mill Smolt Trap on 19 March 2008.

Across 16 measured river 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 Riding Mill.

See river lamprey records across England →

Most recent observation14 May 2008Riding Mill Smolt Trap · 1 fish
Largest measured river lamprey
32 cm
Median length
10.5 cm
Fish measured
16
Survey locations
1

Individual EA measurements

Largest measured river lamprey

The largest individual measurements in this river and species dataset. Equal measurements are retained as separate surveyed fish.

LengthSurvey dateSurvey locationSurvey ID
32 cm19 Mar 2008Riding Mill Smolt Trap119041
31.6 cm21 Apr 2006Riding Mill Smolt Trap113707
31.5 cm19 Apr 2006Riding Mill Smolt Trap113704
30 cm20 Apr 2006Riding Mill Smolt Trap113706
30 cm19 Apr 2004Riding Mill Smolt Trap111518
24 cm26 Apr 2004Riding Mill Smolt Trap111526
13 cm8 Jun 2004Riding Mill Smolt Trap112281
10.5 cm5 May 2006Riding Mill Smolt Trap113844
10.5 cm23 Jun 2005Riding Mill Smolt Trap113614
10.1 cm7 May 2005Riding Mill Smolt Trap112883

Lengths are direct survey measurements. RiverFish does not estimate fish weights from length.

Explore the river

Where river lamprey were found

Each point marks a survey location with at least one river 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 river lamprey
Riding Mill Smolt Trap19 Apr 200414 May 200825

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

2004–2008

Survey records by year

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

Fish measured by surveyors

Measured length distribution

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

Smallest
7.9 cm
Lower quarter
10 cm
Median
10.5 cm
Upper quarter
30 cm
Largest
32 cm

Lengths are direct survey measurements rather than anglers’ catches.

More fish in this river

Explore the River Riding Mill

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

Atlantic salmon Brown / sea trout Dace Minnow Chub 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 →