Roach · Rutilus rutilus

Roach in the River Colne

Largest measured roach: 34.2 cm

The largest roach measured in Environment Agency surveys of the River Colne was 34.2 cm, recorded at Stanwell Moor on 23 May 2013.

Across 8,434 measured roach, the median measured length was 10.6 cm.

Surveyors recorded weights for 559 roach. The median was 2.3 oz (0.066 kg) and the largest recorded weight was 1 lb 8.4 oz (0.692 kg).

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

See roach records across England →

Most recent observation16 July 2026Watford M1 link road · 28 fish

Largest measured roach: 34.2 cm
Median length: 10.6 cm
Fish measured: 8,434
Survey locations: 32

Individual EA measurements

Largest measured roach

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
34.2 cm	23 May 2013	Stanwell Moor	136075
32.4 cm	8 May 1986	Stanwell Road	115697
32.4 cm	11 Feb 1986	Springwell Lane	115940
32.3 cm	15 Jun 2011	Stanwell Moor	126601
30.5 cm	8 May 1986	Stanwell Road	115697
30.3 cm	27 Feb 1986	Packetboat Lane	116023
30.2 cm	8 May 1986	Stanwell Road	115697
29 cm	17 Jun 1986	Harefield Road	116068
29 cm	8 May 1986	Stanwell Road	115697
29 cm	4 Mar 1986	Moor Roundabout	116016

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

Explore the river

Where roach were found

Each point marks a survey location with at least one roach 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 roach
Watford M1 link road	21 Sept 2000	16 Jul 2026	20
Springwell Lane	11 Feb 1986	15 Jun 2026	24
Stanwell Moor	6 Nov 2001	28 May 2026	22
Wall Hall	11 Jul 2003	14 May 2026	21
Uxbridge	20 Aug 2002	4 Jul 2024	18
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
Drop Lane	8 Jul 2003	28 Jun 2018	11
The Withey Beds	20 May 2015	15 May 2017	2
Merchant Taylors CPUE	21 Sept 2015	21 Sept 2015	1
Merchant Taylor	27 Jun 2007	21 Sept 2015	4
Denham	20 Oct 1998	16 Jul 2015	8
u/s West Drayton Mill	24 Sept 2013	30 Sept 2014	2
Merchant Taylor Backwater	16 Sept 2013	16 Sept 2013	1
Longbridge Way, Uxbridge	29 May 2012	29 May 2012	1
Cowley, Old Mill Lane	19 May 2009	19 May 2009	1
Elms Lake	19 Feb 2004	19 Feb 2004	1
Harefield Road	17 Jun 1986	17 Jun 1986	1
Old Mill Lane	12 Jun 1986	12 Jun 1986	1
Stanwell Road	8 May 1986	8 May 1986	1
Poyle Channel	7 May 1986	7 May 1986	1
Staines Moor	13 Mar 1986	13 Mar 1986	1
Moor roundabout 2	12 Mar 1986	12 Mar 1986	1
Staines	11 Mar 1986	11 Mar 1986	1
Moor Roundabout	4 Mar 1986	4 Mar 1986	1
Packetboat Lane	27 Feb 1986	27 Feb 1986	1
Milupa Factory	20 Feb 1986	20 Feb 1986	1
Denham Court	19 Feb 1986	19 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 roach that year.

1486

087

088

089

090

091

092

093

094

095

096

097

198

099

100

301

302

703

804

705

706

807

708

809

610

311

712

513

414

915

416

617

618

719

020

021

522

523

524

425

426

Fish measured by surveyors

Measured length distribution

See how the 8,434 measured fish were spread across different length ranges.

Smallest: 1 cm
Lower quarter: 7.7 cm
Median: 10.6 cm
Upper quarter: 13.7 cm
Largest: 34.2 cm

0–99 mm

3628

100–199 mm

4515

200–299 mm

284

300–399 mm

Lengths are direct survey measurements rather than anglers’ catches.

Fish weighed by surveyors

Measured weight summary

Recorded weights were available for 559 roach. This is a subset of the measured fish and may not represent the whole population.

Lightest: 0 oz (0.0001 kg)
Lower quarter: 0.8 oz (0.0239 kg)
Median: 2.3 oz (0.066 kg)
Upper quarter: 5.3 oz (0.149 kg)
Heaviest: 1 lb 8.4 oz (0.692 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.

Chub Perch Pike Dace Gudgeon Bullhead

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 →