RiverFish

Roach · Rutilus rutilus

Roach in the Grand Union Canal

Largest measured roach: 35.1 cm

The largest roach measured in Environment Agency surveys of the Grand Union Canal was 35.1 cm, recorded at Berkhamsted on 31 March 1987.

Across 3,961 measured roach, the median measured length was 14.2 cm.

Surveyors recorded weights for 1,500 roach. The median was 1.3 oz (0.036 kg) and the largest recorded weight was 1 lb 14.1 oz (0.854 kg).

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

See roach records across England →

Most recent observation4 June 2013u/s Widewater Lock · 6 fish
Largest measured roach
35.1 cm
Median length
14.2 cm
Fish measured
3,961
Survey locations
18

Individual EA measurements

Largest measured roach

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

LengthSurvey dateSurvey locationSurvey ID
35.1 cm31 Mar 1987Berkhamsted116251
33 cm4 Apr 1987Berkhamsted116238
33 cm31 Mar 1987Berkhamsted116251
30.6 cm3 Mar 1988Winkwell Lane, Bourne End116491
29.9 cm3 Mar 1988Winkwell Lane, Bourne End116491
29.6 cm3 Mar 1988Winkwell Lane, Bourne End116491
29.2 cm3 Mar 1988Winkwell Lane, Bourne End116491
28.8 cm5 Nov 1987Stockley Road116118
28.8 cm4 Apr 1987Berkhamsted116238
28.5 cm18 Mar 1988Coppermill Lane, Rickmansworth116490

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 surveyedFirst recordedLast recordedVisits finding roach
u/s Widewater Lock4 Jun 20134 Jun 20131
Slough Arm at Iver North STW26 Apr 198826 Apr 19881
Hunton Bridge21 Apr 198821 Apr 19881
Hanwell29 Mar 198829 Mar 19881
Kensal Road25 Mar 198825 Mar 19881
Victoria Park23 Mar 198823 Mar 19881
Coppermill Lane, Rickmansworth18 Mar 198818 Mar 19881
Cassiobury Park u/s Lock9 Mar 19889 Mar 19881
Stockers Farm8 Mar 19888 Mar 19881
Winkwell Lane, Bourne End3 Mar 19883 Mar 19881
Slough Arm at B470 Road29 Feb 198829 Feb 19881
Stockley Road5 Nov 19875 Nov 19871
Horsendon Lane5 Jun 19875 Jun 19871
Bankside3 Jun 19873 Jun 19871
The Common13 May 198713 May 19871
Berkhamsted31 Mar 19874 Apr 19872
Johnsons Lock17 Mar 198717 Mar 19871
York Way9 Dec 19869 Dec 19861

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

1986–2013

Survey records by year

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

Fish measured by surveyors

Measured length distribution

See how the 3,961 measured fish were spread across different length ranges.

Smallest
0.5 cm
Lower quarter
11 cm
Median
14.2 cm
Upper quarter
17.4 cm
Largest
35.1 cm

Lengths are direct survey measurements rather than anglers’ catches.

Fish weighed by surveyors

Measured weight summary

Recorded weights were available for 1,500 roach. This is a subset of the measured fish and may not represent the whole population.

Lightest
0 oz (0.001 kg)
Lower quarter
0.5 oz (0.014 kg)
Median
1.3 oz (0.036 kg)
Upper quarter
3 oz (0.086 kg)
Heaviest
1 lb 14.1 oz (0.854 kg)

These are direct individual weights recorded by Environment Agency surveyors. Combined bulk weights are not included.

More fish in this river

Explore the Grand Union Canal

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

Perch Pike Common bream Gudgeon European eel Tench

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 →