Individual EA measurements
Largest measured bullhead
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 |
|---|---|---|---|
| 9.8 cm | 1 Aug 2022 | Springwell Lane | 161671 |
| 9.8 cm | 1 Dec 2004 | Denham | 83313 |
| 9.8 cm | 8 Jul 2003 | Drop Lane | 76368 |
| 9.5 cm | 1 Dec 2004 | Denham | 83313 |
| 9.5 cm | 12 Mar 1986 | Moor Roundabout | 116072 |
| 9.4 cm | 1 Aug 2022 | Springwell Lane | 161671 |
| 9.4 cm | 7 Jul 2015 | Watford M1 link road | 145318 |
| 9.3 cm | 8 Jul 2003 | Drop Lane | 76368 |
| 9.2 cm | 26 Feb 1986 | Uxbridge Moor | 116028 |
| 9.1 cm | 9 Aug 2005 | Springwell Lane | 86949 |
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 surveyed | First recorded | Last recorded | Visits finding bullhead |
|---|---|---|---|
| Uxbridge | 20 Aug 2002 | 21 Jul 2026 | 18 |
| Watford M1 link road | 10 Jul 2003 | 16 Jul 2026 | 17 |
| Springwell Lane | 11 Feb 1986 | 15 Jun 2026 | 20 |
| Stanwell Moor | 16 Aug 2002 | 28 May 2026 | 15 |
| Wall Hall | 11 Jul 2003 | 14 May 2026 | 17 |
| Colney Heath | 27 Mar 2013 | 16 Apr 2026 | 3 |
| Drop Lane | 8 Jul 2003 | 23 May 2023 | 6 |
| Watford Tesco Extra | 26 Jul 2022 | 26 Jul 2022 | 1 |
| Lairage Land | 26 Jul 2022 | 26 Jul 2022 | 1 |
| Heathrow EP: Little Britain | 31 Oct 2019 | 31 Oct 2019 | 1 |
| Heathrow EP: Poyle Channel | 28 Oct 2019 | 28 Oct 2019 | 1 |
| Denham 2.0 | 19 Jul 2018 | 19 Jul 2018 | 1 |
| The Withey Beds | 20 May 2015 | 15 May 2017 | 2 |
| Denham | 8 Sept 2003 | 16 Jul 2015 | 7 |
| u/s West Drayton Mill | 30 Sept 2014 | 30 Sept 2014 | 1 |
| Longbridge Way, Uxbridge | 29 May 2012 | 29 May 2012 | 1 |
| Cowley, Old Mill Lane | 19 May 2009 | 19 May 2009 | 1 |
| Merchant Taylor | 27 Jun 2007 | 27 Jun 2007 | 1 |
| Stanwell Road | 8 May 1986 | 8 May 1986 | 1 |
| Staines Moor | 13 Mar 1986 | 13 Mar 1986 | 1 |
| Moor Roundabout | 4 Mar 1986 | 12 Mar 1986 | 2 |
| Packetboat Lane | 27 Feb 1986 | 27 Feb 1986 | 1 |
| Uxbridge Moor | 26 Feb 1986 | 26 Feb 1986 | 1 |
| Maple Cross | 12 Feb 1986 | 12 Feb 1986 | 1 |
| Mill End | 11 Feb 1986 | 11 Feb 1986 | 1 |
Choose a point or table row to see the location. More survey visits can mean more records, but not necessarily more fish.
1986–2026
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 463 measured fish were spread across different length ranges.
- Smallest
- 0.5 cm
- Lower quarter
- 5.8 cm
- Median
- 6.6 cm
- Upper quarter
- 7.4 cm
- Largest
- 9.8 cm
Lengths are direct survey measurements rather than anglers’ catches.
Fish weighed by surveyors
Measured weight summary
Recorded weights were available for 100 bullhead. This is a subset of the measured fish and may not represent the whole population.
- Lightest
- 0 oz (0.001 kg)
- Lower quarter
- 0.2 oz (0.0045 kg)
- Median
- 0.3 oz (0.0074 kg)
- Upper quarter
- 0.4 oz (0.011 kg)
- Heaviest
- 2.4 oz (0.068 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 Colne
Compare other species with enough survey and measurement data for a detailed page.
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 →