Grayling · Thymallus thymallus

Grayling in the Itchen Navigation

Largest measured grayling: 39.3 cm

The largest grayling measured in Environment Agency surveys of the Itchen Navigation was 39.3 cm, recorded at Allbrook Lock on 29 September 2003.

Across 221 measured grayling, the median measured length was 20.6 cm.

Surveyors recorded weights for 75 grayling. The median was 3.1 oz (0.089 kg) and the largest recorded weight was 1 lb 5.8 oz (0.617 kg).

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

See grayling records across England →

Most recent observation27 October 2025Ham Farm · 6 fish

Largest measured grayling: 39.3 cm
Median length: 20.6 cm
Fish measured: 221
Survey locations: 3

Individual EA measurements

Largest measured grayling

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
39.3 cm	29 Sept 2003	Allbrook Lock	77813
39 cm	20 Sept 2013	Ham Farm	138928
38.4 cm	6 Sept 2011	Ham Farm	127925
38 cm	19 Sept 2005	Allbrook Lock	86420
37.3 cm	18 Sept 2002	Allbrook Lock	55075
36 cm	1 Sept 2009	Ham Farm	119588
35.8 cm	19 Sept 2006	Allbrook Lock	102332
35.3 cm	19 Sept 2006	Allbrook Lock	102332
35 cm	20 Sept 2013	Ham Farm	138928
34.4 cm	6 Sept 2011	Ham Farm	127925

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 surveyed	First recorded	Last recorded	Visits finding grayling
Ham Farm	15 Aug 2002	27 Oct 2025	10
Allbrook Lock	18 Sept 2002	19 Sept 2006	5
Tun Bridge	15 Sept 2003	15 Sept 2003	1

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

2002–2025

Survey records by year

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

202

203

104

105

106

007

008

109

010

111

012

113

014

115

016

117

018

119

020

021

122

123

024

125

Fish measured by surveyors

Measured length distribution

See how the 221 measured fish were spread across different length ranges.

Smallest: 7.8 cm
Lower quarter: 17.7 cm
Median: 20.6 cm
Upper quarter: 26.6 cm
Largest: 39.3 cm

0–99 mm

100–199 mm

200–299 mm

300–399 mm

Lengths are direct survey measurements rather than anglers’ catches.

Fish weighed by surveyors

Measured weight summary

Recorded weights were available for 75 grayling. This is a subset of the measured fish and may not represent the whole population.

Lightest: 0.1 oz (0.004 kg)
Lower quarter: 1.8 oz (0.052 kg)
Median: 3.1 oz (0.089 kg)
Upper quarter: 7.5 oz (0.2125 kg)
Heaviest: 1 lb 5.8 oz (0.617 kg)

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

More fish in this river

Explore the Itchen Navigation

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

European eel Pike Minnow Roach Atlantic salmon Brown / sea trout

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 →