RiverFish

Grayling · Thymallus thymallus

Grayling in the River Derwent

Largest measured grayling: 38.9 cm

The largest grayling measured in Environment Agency surveys of the River Derwent was 38.9 cm, recorded at Cromford on 5 July 2006.

Across 909 measured grayling, the median measured length was 23.8 cm.

Surveyors recorded weights for 2 grayling. The median was 4.8 oz (0.135 kg) and the largest recorded weight was 4.9 oz (0.14 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 Derwent.

See grayling records across England →

Most recent observation29 September 2025Duffield Bridge · 2 fish
Largest measured grayling
38.9 cm
Median length
23.8 cm
Fish measured
909
Survey locations
20

Individual EA measurements

Largest measured grayling

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

LengthSurvey dateSurvey locationSurvey ID
38.9 cm5 Jul 2006Cromford99965
38.5 cm19 Aug 2014Hathersage144237
38.4 cm28 Jan 1998Baslow23931
37.5 cm5 Aug 2001Duffield25510
37.5 cm28 Jan 1998Baslow23931
37.1 cm21 Jun 2007Hathersage106041
36.8 cm13 Sept 2018Hathersage153354
36.8 cm12 May 1999Hathersage23447
36.8 cm28 Jan 1998Baslow23931
36 cm19 Aug 2014Hathersage144237

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

Explore the river

Where grayling were found

Each point marks a survey location with at least one grayling 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 grayling
Duffield Bridge4 Sept 201429 Sept 20257
Darley Abbey Net17 Sept 202517 Sept 20251
Hathersage29 Jan 199814 Sept 202214
Cromford Willersley Castle Salmon parr26 Aug 202226 Aug 20221
Belper Weir Salmon Parr17 Oct 201710 Sept 20182
Cromford26 Feb 19986 Sept 201814
Cromford Salmon Parr4 Sept 201417 Oct 20174
Borrowash Fish Pass Pool125 Feb 201616 Sept 20162
DS Longbridge Weir4 Sept 20144 Sept 20141
Borrowash14 Oct 20011 Sept 20134
Grindleford18 Oct 201018 Oct 20101
DS Calver Weir18 Oct 201018 Oct 20101
Nooning Lane Net29 Sept 201029 Sept 20101
Duffield10 Feb 19984 Oct 20098
Nooning Lane16 Feb 199823 Sept 20083
Matlock Bath29 Apr 19933 Sept 20066
Church Wilne11 Sept 200511 Sept 20051
Baslow28 Jan 199815 Jun 20052
Alvaston17 Feb 199817 Feb 19981
Ambergate5 May 19933 Feb 19972

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

1993–2025

Survey records by year

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

Fish measured by surveyors

Measured length distribution

See how the 909 measured fish were spread across different length ranges.

Smallest
1.9 cm
Lower quarter
20.2 cm
Median
23.8 cm
Upper quarter
28.3 cm
Largest
38.9 cm

Lengths are direct survey measurements rather than anglers’ catches.

Fish weighed by surveyors

Measured weight summary

Recorded weights were available for 2 grayling. This is a subset of the measured fish and may not represent the whole population.

Lightest
4.6 oz (0.13 kg)
Lower quarter
4.7 oz (0.1325 kg)
Median
4.8 oz (0.135 kg)
Upper quarter
4.9 oz (0.1375 kg)
Heaviest
4.9 oz (0.14 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 Derwent

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

Brown / sea trout Bullhead Minnow Chub Stone loach Perch

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 →