Brook lamprey  (Lampetra planeri)

Anadromous: In fish: those species that spend most of their lives at sea but migrate to fresh water to spawn.
Larvae: Stage in an animal's lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.

1. UNEP-WCMC (March, 2002)
   http://quin.unep-wcmc.org/
   
2. Environment Agency. (1998) Species Awareness leaflet Number 5. Lamprey. Environment Agency, Bristol.
   
3. Conserving Natura 2000 Rivers: River, Brook and Sea Lamprey (September, 2008)
   http://www.english-nature.org.uk/lifeinukrivers/species/lamprey.html
   
4. Davies, C., Shelley, J., Harding, P., McLean, I., Gardiner, R. and Peirson, G. (2004) Freshwater Fishes in Britain – The Species and their Distribution. Harley Books, Colchester.
   
5. Cihar, J. (1991) A Field Guide in Colour to Freshwater Fish. Aventium publishing, Prague.
   
6. Fishbase (March, 2002)
   http://www.fishbase.org/Summary/SpeciesSummary.cfm?ID=4481&genusname=Lampetra&speciesname=planeri
   
7. JNCC (September, 2008)
   http://www.jncc.gov.uk/ProtectedSites/SACselection/species.asp?FeatureIntCode=S1096