RiverFish

Perch · Perca fluviatilis

Perch in the River Colne

Largest measured perch: 39.9 cm

The largest perch measured in Environment Agency surveys of the River Colne was 39.9 cm, recorded at Merchant Taylor on 26 August 2009.

Across 3,124 measured perch, the median measured length was 10 cm.

Surveyors recorded weights for 373 perch. The median was 1.7 oz (0.048 kg) and the largest recorded weight was 14.6 oz (0.413 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 perch records across England →

Most recent observation21 July 2026Uxbridge · 45 fish
Largest measured perch
39.9 cm
Median length
10 cm
Fish measured
3,124
Survey locations
34

Individual EA measurements

Largest measured perch

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

LengthSurvey dateSurvey locationSurvey ID
39.9 cm26 Aug 2009Merchant Taylor118660
36.9 cm26 Jun 2008Wall Hall111525
36.6 cm6 Jun 2007Wall Hall105531
36 cm31 Oct 2019Heathrow EP: Little Britain155857
35.3 cm25 Jul 2006Wall Hall100434
35 cm26 Jun 2008Wall Hall111525
35 cm6 Jul 2005Wall Hall84993
34.5 cm10 Jul 2003Watford M1 link road76370
34.4 cm27 May 2009Wall Hall117283
34 cm4 Jul 2024Uxbridge166483

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

Explore the river

Where perch were found

Each point marks a survey location with at least one perch 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 perch
Uxbridge29 Mar 199921 Jul 202621
Watford M1 link road21 Sept 200016 Jul 202616
Springwell Lane11 Feb 198615 Jun 202623
Stanwell Moor6 Nov 200128 May 202622
Wall Hall11 Jul 200314 May 202620
Drop Lane8 Jul 200323 May 202311
Lairage Land26 Jul 202226 Jul 20221
Heathrow EP: Little Britain31 Oct 201931 Oct 20191
Heathrow EP: Poyle Channel28 Oct 201928 Oct 20191
Denham 2.019 Jul 201819 Jul 20181
The Withey Beds20 May 201515 May 20172
Merchant Taylors CPUE21 Sept 201521 Sept 20151
Merchant Taylor26 Aug 200921 Sept 20153
u/s West Drayton Mill24 Sept 201330 Sept 20142
Merchant Taylor Backwater16 Sept 201316 Sept 20131
Denham20 Oct 199826 Jun 20129
Longbridge Way, Uxbridge29 May 201229 May 20121
Cowley, Old Mill Lane19 May 200919 May 20091
Elms Lake19 Feb 200419 Feb 20041
Harefield Road17 Jun 198617 Jun 19861
Old Mill Lane12 Jun 198612 Jun 19861
Cricketfield Lane16 May 198616 May 19861
Stanwell Road8 May 19868 May 19861
Poyle Channel7 May 19867 May 19861
Moor roundabout 212 Mar 198612 Mar 19861
Staines11 Mar 198611 Mar 19861
Moor Roundabout4 Mar 19864 Mar 19861
Packetboat Lane27 Feb 198627 Feb 19861
Uxbridge Moor26 Feb 198626 Feb 19861
Milupa Factory20 Feb 198620 Feb 19861
Denham Court19 Feb 198619 Feb 19861
Troy House18 Feb 198618 Feb 19861
Maple Cross12 Feb 198612 Feb 19861
Mill End11 Feb 198611 Feb 19861

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 perch that year.

Fish measured by surveyors

Measured length distribution

See how the 3,124 measured fish were spread across different length ranges.

Smallest
0.7 cm
Lower quarter
7.1 cm
Median
10 cm
Upper quarter
14 cm
Largest
39.9 cm

Lengths are direct survey measurements rather than anglers’ catches.

Fish weighed by surveyors

Measured weight summary

Recorded weights were available for 373 perch. This is a subset of the measured fish and may not represent the whole population.

Lightest
0 oz (0.001 kg)
Lower quarter
0.4 oz (0.0113 kg)
Median
1.7 oz (0.048 kg)
Upper quarter
3.2 oz (0.092 kg)
Heaviest
14.6 oz (0.413 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 Roach 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 →