RiverFish

Bullhead · Cottus gobio

Bullhead in the Main River Mole

Largest measured bullhead: 8.7 cm

The largest bullhead measured in Environment Agency surveys of the Main River Mole was 8.7 cm, recorded at North Heasley Mine (Te) on 8 August 2016.

Across 435 measured bullhead, the median measured length was 5.1 cm.

Surveyors recorded one individual weight: 1.8 oz (0.051 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 River Mole.

See bullhead records across England →

Most recent observation19 August 2025Mole Bride (Dip) · 19 fish
Largest measured bullhead
8.7 cm
Median length
5.1 cm
Fish measured
435
Survey locations
20

Individual EA measurements

Largest measured bullhead

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

LengthSurvey dateSurvey locationSurvey ID
8.7 cm8 Aug 2016North Heasley Mine (Te)148844
8.5 cm22 Jun 2018North Heasley Mine (Te)152692
8.1 cm21 Aug 2018South Wood (Sp)153264
7.8 cm21 Aug 2018Heasley Mill (Sp)153464
7.8 cm21 Aug 2018South Wood (Sp)153264
7.6 cm19 May 2022Upstream Riverside Caravan Park161076
7.6 cm21 Aug 2018Heasley Mill (Sp)153464
7.6 cm21 Aug 2018Heasley Mill (Sp)153464
7.6 cm21 Aug 2018Heasley Mill (Sp)153464
7.6 cm21 Aug 2018Heasley Mill (Sp)153464

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

Explore the river

Where bullhead were found

Each point marks a survey location with at least one bullhead 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 bullhead
Mole Bride (Dip)2 Sept 199619 Aug 20256
Wampford Bridge (Dip)3 Sept 199618 Aug 20255
South Wood (Sp)13 Aug 199618 Aug 20256
Heasley Mill (Sp)12 Aug 199613 Aug 20255
South Molton Rugby Ground (Sp)5 Aug 20255 Aug 20251
North Heasley Mine (Te)12 Aug 199610 Jul 202517
South Wood (5 min)18 Sept 202318 Sept 20231
North Molton (5 min)13 Aug 199618 Sept 20236
Bicknor Top Site (5 min)19 Oct 200718 Sept 20232
North Heasley Mine (5 min)24 Jul 202324 Jul 20231
Upstream Riverside Caravan Park1 Aug 201924 May 20234
Parkhouse*13 Aug 199624 May 20236
Little Hele Wood (Dip)*3 Sept 199624 May 20236
Head Bridge (Dip)3 Sept 199627 Sept 20184
Higher Water Town (Dip)*3 Sept 199611 Sept 20122
South Molton (Dip)*3 Sept 19967 Sept 20123
Coppice Field (Sp)*7 Sept 20062 Sept 20094
Bicknor Bridge - coppice (Dip)*19 Oct 200719 Oct 20071
Alswear (Dip)*21 Aug 199630 Aug 20053
Lenton (Dip)*3 Sept 19963 Sept 19961

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

1996–2025

Survey records by year

Each bar shows how many survey visits recorded bullhead that year.

Fish measured by surveyors

Measured length distribution

See how the 435 measured fish were spread across different length ranges.

Smallest
1.6 cm
Lower quarter
3.4 cm
Median
5.1 cm
Upper quarter
6 cm
Largest
8.7 cm

Lengths are direct survey measurements rather than anglers’ catches.

Fish weighed by surveyors

Measured weight summary

One individual weight was recorded for this fish and river. This is a subset of the measured fish and may not represent the whole population.

Recorded weight
1.8 oz (0.051 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 River Mole

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

Brown / sea trout Atlantic salmon European eel Stone loach 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 →