Lampetra fluviatilis | River Lamprey



Conservation status

Future Prospects
Overal Assessment of Conservation Status
Overal trend in Conservation Status
N / A

*Note that for the reporting period 2007-2012 that the River Lamprey and Brook Lamprey were assessed jointly.

Source: NPWS 2013.

IUCN Conservation Status
Ireland (1)
Least Concern
Europe (2)
Least Concern
Global (2)
Least Concern

Source (1): King, J.L. et al 2011  : Source (2) Freyhof, J. 2013.

Legal status

Protected by the following legal instruments:

  • Habitats Directive [92/42/EEC] Annex II, Annex V
  • Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention) Appendix III
  • Fisheries Acts 1959 to 2006
  • Fisheries Act (Northern Ireland) 1966
  • Foyle Fisheries Act (NI) 1952
  • Foyle and Carlingford Fisheries Act 2007.
Sources:King, J.L. et al 2011; Maitland, Peter S., 2004.

Native status


Species Biology


  • Agnathus (jawless) fish with mouth a sucker like disc instead.

  • In Lampetra fluviatilis there are relatively few teeth on the sucking disc, but teeth are sharp

  • Adults are rather eel like in shape but lack paired fins although dorsal and caudal fins are present.
  • Has a single rather than a pair of nostrils and this between rather than in front of its eyes.
  • Has a line of seven gill openings behind each eye.
  • The adult of this species is intermediate in size between the larger Sea Lamprey (P. marinus) and the smaller Brook lamprey (Lampetra planeri).
  • Adults can grow to 50cms but usual length is 30cms and almost always over 17cms.

  • Colouration in adults is dark grey or olive green dorsally, fading to ochre laterally then much paler ventrally.
  • There is no black mottling as in adult Sea Lamprey.

Sources: Maitland, P.S., 2003;Maitland, Peter S., 2004.


Predominantly anadromous, breeding in freshwater as adults with offspring migrating to sea after a freshwater phase prior to maturation.

In the freshwater phase high quality waters are most beneficial for this species  with adults needing clean gravel beds for spawning, the ammocoetes requiring silty sands in high quality freshwater.

Habitats include but are not necessarily limited to;

  • Eroding / upland rivers (FW1)
  • Depositing / lowland rivers (FW2)
  • Marine water body (M)

Sources: Maitland P.S., 2003; Maitland, Peter S., 2004.


Spawning March-April. A redd or nest is excavated by the male in gravel substrate. Fertilisation takes place externally in the redd. Males and females die after spawning.
Ammocoetes (larvae) hatch after 15-30 days.On hatching ammocoetes drift downstream to embed in silty substrate where they live as filter feeders for up to 5 years. Metamorphosis from ammocoete to adult is described as taking up to four months.
Following metamorphisis migration to sea follows, the timing of which occurs from autumn to late spring. 12-24 months are spent at sea. From metamorphosis this species is parasitic on other fish species using teeth to attach to host.

Return to freshwater is timed from October to December.

Source: Maitland P.S., 2003.

Threats faced

Reduction in migration / migration barriers  
Dredging / removal of limnic sediments 
Invasive non-native species
Diffuse pollution to surface waters due to agricultural and forestry activities
H01.05 High
Other point source pollution to surface waters 
H01.03 High
Siltation rate changes,dumping, depositing of dredged deposits
J02.11 Medium
Bait digging / collection

The threat category 'Reduction in migration / migration barriers'  relates to obstruction to returning adults in accessing suitable habitat for spawning and / or limiting the natural freshwater range available for the species.

Source: NPWS 2013.

Conservation actions

In the Article 17 Habitats Directive reporting for the period 2007-2012 Conservation Measures implemented or being implemented during the period

  • Continued legal protection of the species and its habitats inside and outside of Natura 2000 sites.
  • Other wetland related measures* inside and outside of Natura 2000 sites.

*In guidance notes for Article 17 reporting 'other wetland-related measures' can include 'restoring / improving the hydrological regime' which could include 'removal of barriers and artificial margins'.

Sources: NPWS 2013; European Topic Centre on Biological Diversity Website.


World distribution(GBIF)

Distribution is European from southern Norway to France including Britain and Ireland, the Baltic, and the western to middle north Mediterranean. Landlocked populations occur.

Source: Maitland, Peter S., 2004.

Accuracy of world distribution shown in the Global Biodiversity Information Facility (GBIF) map below will be constrained by, amongst other factors, data held but not shared by countries and organizations not participating in the GBIF.

Irish distribution

Based on surveys of adults, the species would appear concentrated in rivers in the south east with populations spread over a similar range to the Sea Lamprey (Petromyzon marinus) i.e. rivers that run in to the sea along the north, west and south coasts. Difficulties with distinguishing the young stages of the River Lamprey and Brook Lamprey (Lampetra planeri) mean that actual distribution may be different.

Sources: Igoe et al 2004; King et al 2011.

Temporal change

Records submitted to Data Centre in 2021

The following map is interactive. If you would prefer to view it full screen then click here.

How can you help

The National Biodiversity Data Centre is trying to improve our knowledge on the distribution of the River Lamprey in Ireland. Should you observe the species, please submit sighting to add to the database. Detailed observations will assist us gaining a better insight into where the species is most abundant in Ireland and we might also be able to detect regional variations. Please submit any sightings and photographs at:

All records submitted on line can be viewed on Google Maps – once checked and validated these will be added to the database and made available for conservation and research.

Further information

For further information contact Dr. Liam Lysaght



Fossitt, J.A. (2001). A Guide to Habitats in Ireland. The Heritage Council.

Freyhof, J. 2013. Lampetra fluviatilis. The IUCN Red List of Threatened Species. Version 2014.2. <>. Downloaded on 21 September 2014

Igoe F.,  Quigley D.T.G.,  Marnell F.,  Meskell E., O’Connor W. and Byrne, C. (2004). The Sea Lamprey Petromyzon marinus (L.), River Lamprey Lampetra fluviatilis (L.) and Brook Lamprey Lampetra planeri (Bloch) In Ireland: General Biology, Ecology, Distribution and Status with Recommendations for Conservation. Biology and Environment: Proceedings Of The Royal Irish Academy,Vol.104b, No.3, 43/56

Kelly, Fiona L. and King, James J.   (2001) A review of the ecology and distribution of three lamprey species, Lampetra fluviatilis (l.)., Lampetra planeri (Bloch) and Petromyzon marinus (l.): A context for conservation and biodiversity considerations in Ireland Biology And Environment :Proceedings Of The Royal Irish Academy,Vol. 101B, No. 3, 165 – 185)

King, J.L., Marnell, F., Kingston, N., Rosell, R., Boylan, P., Caffrey, J.M., FitzPatrick, Ú., Gargan, P.G., Kelly, F.L., O’Grady, M.F., Poole, R., Roche, W.K. & Cassidy, D. (2011) Ireland Red List No. 5: Amphibians, Reptiles & Freshwater Fish. National Parks and Wildlife Service, Department of Arts, Heritage and the Gaeltacht, Dublin, Ireland.

Maitland PS (2003). Ecology of the River, Brook and Sea Lamprey. Conserving Natura 2000 Rivers Ecology Series No. 5. English Nature, Peterborough

Maitland, Peter S., (2004). Keys to the Freshwater Fish of Britain and Ireland With Notes on Their Distribution and Ecology. The Freshwater Biological Society, Cumbria.

NPWS (2013) The Status of EU Protected Habitats and Species in Ireland.  Species Assessments Volume 3. Version 1.0. Unpublished Report, National Parks & Wildlife Services. Department of Arts, Heritage and the Gaeltacht, Dublin, Ireland.