Historic monitoring evidence · Environment Agency
Tewin Flyfishers
Hertfordshire and North London · survey site
This page records ecological survey evidence. It is not proof of current fish presence, abundance, fishing quality, access, permission or safety at this location.
Observed taxa
What monitoring recorded here
Taxa are ordered by latest survey date. Counts and records reflect monitoring events, not an angling forecast.
Brown / sea trout
Salmo trutta- First record
- 5 Apr 2007
- Latest record
- 25 Sept 2025
- Survey events
- 18
Grayling
Thymallus thymallus- First record
- 5 Apr 2007
- Latest record
- 25 Sept 2025
- Survey events
- 17
Bullhead
Cottus gobio- First record
- 3 Oct 2007
- Latest record
- 25 Sept 2025
- Survey events
- 17
3-spined stickleback
Gasterosteus aculeatus- First record
- 5 Apr 2007
- Latest record
- 25 Sept 2025
- Survey events
- 16
Stone loach
Barbatula barbatula- First record
- 5 Apr 2007
- Latest record
- 25 Sept 2025
- Survey events
- 15
Brook lamprey ammocoetes
Lampetra planeri- First record
- 23 Sept 2019
- Latest record
- 23 Sept 2019
- Survey events
- 1
Rudd
Scardinius erythrophthalmus- First record
- 26 Sept 2013
- Latest record
- 26 Sept 2013
- Survey events
- 1
10-spined stickleback
Pungitius pungitius- First record
- 3 Oct 2007
- Latest record
- 3 Oct 2007
- Survey events
- 1
Rules and access
Check before you travel.
Environment Agency ecology records do not carry fishing-rights boundaries or live restrictions. Confirm the fishery owner, permission, local byelaws, seasonal rules, safety notices and current conditions before setting out.
Check live freshwater fishing rulesProvenance
Source, licence and boundary
- SourceEnvironment Agency Ecology & Fish Data
- LicenceOpen Government Licence v3.0
- Source copy retrieved23 Jul 2026
- Terms checked23 Jul 2026
- CoverageHistoric monitoring evidence, separately dated per record
- Not assertedCurrent presence, access, permission, fishing quality or safety