Morphological analysis of geographic variation of sea lamprey ammocoetes in Portuguese river basins |
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Authors: | P R Almeida G Tomaz N O Andrade B R Quintella |
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Institution: | (1) Department of Biology, University of Evora, 7002-554 Evora, Portugal;(2) Institute of Oceanography, Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016 Lisbon, Portugal |
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Abstract: | The main objective of this study was to compare the morphological variability of sea lamprey (Petromyzon marinus L.) larvae from the main Portuguese river basins. Samples were collected in rivers Minho, Lima, Cávado, Vouga, Mondego, Tejo
and Guadiana. Specimens were analysed in terms of morphometric (linear body measures) and meristic (number of myomeres) characters
to investigate the hypothesis of population fragmentation between river basins caused by some degree of homing behaviour.
The discriminant analysis showed a morphological segregation of the studied populations based on the characters head, tail
and branchial length. The discriminatory power of the meristic characters was comparatively weaker, with the number of trunk
myomeres, and to some extent the head myomeres, being responsible for the reduced separation between groups. Both analyses
were consistent in identifying the cephalic region as the most important morphological feature to discriminate populations
of sea lamprey larvae in the Portuguese territory. The largest cephalic region of the ammocoetes sampled in the northern river
basins may be responsible for a better feeding efficiency and, consequently, higher values of condition factor.
Guest editors: S. Dufour, E. Prévost, E. Rochard & P. Williot
Fish and diadromy in Europe (ecology, management, conservation) |
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Keywords: | Petromyzon marinus Morphometric Meristic Condition factor Transformers |
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