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.
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.
Cihar, J. (1991) A Field Guide in Colour to Freshwater Fish. Aventium publishing, Prague.