Journal of Fish Biology (2014) doi:10.1111/jfb.12513, available online at wileyonlinelibrary.com BRIEF COMMUNICATION Different stocks of brook lamprey in Spain and their origin from Lampetra luviatilis at two distinct times and places A. M. Pereira*†, I. Doadrio‡, J. I. Robalo* and V. C. Almada* *Marine and Environmental Sciences Centre and Eco-Ethology Research Unit, ISPA–Instituto Universitário Rua Jardim do Tabaco 34 1149-041 Lisboa, Portugal and ‡National Museum of Natural Sciences, CSIC, José Gutiérrez Abascal 2, 28006 Madrid, Spain Using the mitochondrial non-coding region I, it was shown that the two Spanish Lampetra planeri pop- ulations (Cares–Deva and Olabidea–Ugarana) correspond to different genetic units. The Cares–Deva population is probably a recent offshoot of Lampetra luviatilis, being the Olabidea – Ugarana popula- tion less diverse and of older origin. © 2014 The Fisheries Society of the British Isles Key words: Lampetra planeri; non-coding region I; phylogeography. Lampreys (Petromyzontidae) are remarkable not only for their assortment of very prim- itive characteristics but also for their diverse life histories and patterns of speciation (Hardisty, 2006). All lampreys spawn in fresh water and have a larval phase that typ- ically lasts for several years. The eyeless ammocoetes, which are ilter feeders, live buried in the sediment. After metamorphosis, their development may take two courses: individuals may migrate downstream spending one or more years in the sea or lakes, where they adopt a parasitic or predatory way of life, growing to a much larger size. Upon the approach of sexual maturation, they migrate back into fresh water where they spawn and die. Alternatively, recently metamorphosed lampreys may remain in fresh water without feeding, reach sexual maturity at a much smaller size, spawn and die after a short period (Kottelat & Freyhof, 2007). A common phenomenon in the evolution of lampreys is the formation of these non-migratory freshwater species from wider distributed migratory larger ones (Zanandrea, 1959; Hardisty, 2006). These satellite species have been recognized in eight genera (Lang et al., 2009). It is still a matter of debate on how speciation in brook lampreys occurs (Docker, 2009). One hypothesis is that it occurs in sympatry, by size-assortative mating. Alternatively, it could be a gradual process facilitated by conditions where gene low between the migratory and non-migratory forms is blocked or reduced due to a change in the distribution of the migratory form. †Author to whom correspondence should be addressed. Tel.: +351 21 881 17 00; email: ana_pereira@ispa.pt 1 © 2014 The Fisheries Society of the British Isles