Figure 1.
Location of the river basins from which sea lamprey individuals were collected.
Formation of the three groups (testing hypothesis) based on the geographical location of the river mouth and the proximity to western Iberian oceanic areas with the representation of the seamounts and canyons that contour the three abyssal plains. Acronyms: Iberia AP - Iberia Abyssal Plain; Tagus AP – Tagus Abyssal Plain; Horsheshoe AP – Horsheshoe Abyssal Plain; T – Tore Seamount; ES – Estremadura Spur; G – Gorringe Bank.
Figure 2.
Schematic representation of the morphological features recorded for the analysis of geographic variation of sea lamprey in Portugal.
(a) lateral view outline with the representation of the measured morphometric characters: TL, total length; d, disc length; d-a, distance between disc and anus; a-C, tail length; B7-C, postbranchial length; B7-a, trunk length; d-D1, predorsal distance; d-eD1, distance between disc and posterior end of first dorsal fin; d-D2, distance between disc and base of second dorsal fin; D2-C, dorsal part of caudal fin length; lD1, first dorsal fin length; lD2, second dorsal fin length; D-D, distance between dorsal fins; H, body depth; d-O, preocular distance; O, eye diameter; O-B1, postocular length; Hco, head depth; d-B1, prebranchial length; B1-B7, branchial length; d- B7, head length; d-n, prenostril length; IO, interocular distance; HW, head width; (b) photograph of the oral disc with the representation of the counted meristic characters: AF, anterior field; LFR, lateral right field; LFL, lateral left field; PF, posterior field; SO, supraoral lamina; L, lingual lamina; IO, infraoral lamina; TNteeth, total number of teeth; AFteeth, number of teeth in the anterior field; LFteeth, number of teeth in the lateral field; PFteeth, number of teeth in the posterior field; TNrows, total number of rows; AFrows, number of rows in the anterior field; LFrows, number of rows in the lateral field; PFrows, number of rows in the posterior field; IOcusps, number of cusps in the infra-oral lamina).
Table 1.
MANOVA multivariate test with sex and geographical groups as factors, and adjusted morphometric characters as dependent variables.
Table 2.
Mean of adjusted morphometric characters used for the morphological analysis of P. marinus.
Table 3.
PERMANOVA results for the two-way crossed design, with geographical group and sex as factors, and meristic characters as variables.
Figure 3.
Plot of the discriminant Z scores and group centroids of discriminate functions 1 and 2 for the three groups of adult sea lampreys based on (a) morphometric characters and (b) fatty acid composition of heart total lipids.
▵ - Group 1: Minho, Lima, Cávado, Douro, Vouga and Mondego basins; ○ - Group 2: Tagus; ▿ - Group 3: Guadiana.
Table 4.
Classification results obtained with the stepwise discriminant analysis cross-validation for morphometric characters to determine the predictive accuracy level of the discriminant functions.
Table 5.
Summary of discriminant loadings and potency index for morphometric and meristic variables.
Table 6.
Summary statistics for the meristic characters analysed in the sub sample of 201 sea lamprey individuals included.
Table 7.
Mean (± standard deviation) heart total mass (HTM, g), heart total mass/body gutted mass ratio (HTM/BGM expressed in percentage), mean heart total lipids (HTLip, expressed in g per g of dry tissue), heart water loss (HWater, expressed as percentage) and sex ratio of sea lamprey individuals analysed.
Table 8.
Relative amounts, as percentage of sum (mean ± sd), of fatty acids in heart tissue total lipids of sea lamprey individuals analysed.
Table 9.
Classification results obtained with the stepwise MDA cross-validation for heart tissue fatty acids to determine the predictive accuracy level of the discriminant functions.