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On the absence of genetic differentiation between morphotypes of the ballan wrasse Labrus bergylta (Labridae)

Publication . Almada, Frederico José Oliveira de; Casas, Laura; Francisco, Sara Martins; Villegas-Ríos, David; Saborido-Rey, Fran; Irigoien, Xabier; Robalo, Joana Isabel

The ballan wrasse, Labrus bergylta (Labridae), is a protogynous hermaphrodite fish common in the north-eastern Atlantic from Norway to Morocco. It is a commercially important resource for local fisheries and is currently being used as cleaner fish to control sea lice in salmon farms in northern Europe. Two distinct colour patterns have been recently reported in the literature: plain and spotted. These individuals follow strikingly different life history strategies raising the question of whether they represent one or two independent taxonomic units. Analyses of mitochondrial (18S, COI and control region) and nuclear (S7) markers revealed no genetic differences between these morphotypes. Alternative explanations for the origin and persistence of distinct morphotypes are discussed.

2016Journal article

Restricted access

Historical gene flow constraints in a northeastern atlantic fish: Phylogeography of the ballan wrasse labrus bergylta across its distribution range

Publication . Almada, Frederico José Oliveira de; Francisco, Sara Martins; Lima, Cristina Silva; Fitzgerald, Richard; Mirimin, Luca; Villegas-Ríos, David; Saborido-Rey, Fran; Afonso, Pedro; Morato, Telmo; Bexiga, Sérgio; Robalo, Joana Isabel

The distribution and demographic patterns of marine organisms in the north Atlantic were largely shaped by climatic changes during the Pleistocene, when recurrent glacial maxima forced them to move south or to survive in northern peri-glacial refugia. These patterns were also influenced by biological and ecological factors intrinsic to each species, namely their dispersion ability. The ballan wrasse (Labrus bergylta), the largest labrid fish along Europe's continental margins, is a target for fisheries and aquaculture industry. The phylogeographic pattern, population structure, potential glacial refugia and recolonization routes for this species were assessed across its full distribution range, using mitochondrial and nuclear markers. The existence of a marked population structure can reflect both recolonization from three distinct glacial refugia and current and past oceanographic circulation patterns. Although isolated in present times, shared haplotypes between continental and Azores populations and historical exchange of migrants in both directions point to a common origin of L. bergylta. This situation is likely to be maintained and/or accentuated by current circulation patterns in the north Atlantic, and may lead to incipient speciation in the already distinct Azorean population. Future monitoring of this species is crucial to evaluate how this species is coping with current environmental changes.

2017Journal article

Open access

Identification of adult and juvenile Atherina presbyter Cuvier, 1829 in a marine coastal area adjacent to Tagus estuary (NE Atlantic): A molecular tool for an ecological question

Publication . Almada, Frederico José Oliveira de; Carpi, Piera; Carlos, Fábio Ferreira; Francisco, Sara Martins; Faria, Ana Margarida; Lungu, Ruxanda; Coelho, Pedro Duarte; Neto, José; Gonçalves, Emanuel João; Robalo, Joana Isabel

A simple PCR-RFLP consisting in the digestion of a fragment of the 12S ribosomal RNA (12SrRNA) with species-specific restriction enzymes (MboII and HinfI) was developed to distinguish northeastern Atlantic species in the genus Atherina. Unambiguous identification of morphologically similar sympatric species is frequently difficult, especially when younger specimens are included in the analysis. Genetic and morphological analysis of a total of 123 atherinids collected near the mouth of the Tagus estuary (west Portugal) confirmed that only Atherina presbyter (sand smelt) adults and juveniles are recurrently using these marine rocky habitats as spawning and nursery grounds, respectively. The importance of applying non-destructive methods is emphasized. In the future, the conditions involved in the transition from marine A. presbyter to estuarine/ riverine A. boyeri should be further evaluated along with the ability of larvae and juveniles to cope with river flow and tidal currents drift.

2017Journal article

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Mitochondrial and nuclear intraspecific variation in the rusty blenny (Parablennius sanguinolentus, Blenniidae)

Publication . Pappalardo, Anna Maria; Francisco, Sara M.; Fruciano, Carmelo; Lima, Cristina Silva.; Pulvirenti, Valentina; Tigano, C.; Robalo, Joana Isabel; Ferrito, V.

The genetic structure of Parablennius sanguinolentus from the northeastern Atlantic and Mediterranean was assessed using sequences from the mitochondrial control region (CR) and the first intron of the nuclear S7 ribosomal protein gene (S7). Our data show high genetic diversity for the central Mediterranean populations, contrasting with very low diversity in the Atlantic populations and in the westernmost Mediterranean population of Cabo de Gata. Both CR mismatch analysis and neutrality tests provide evidence of demographic and spatial expansion for the Atlantic and central Mediterranean populations. The significant correlation between genetic and geographic distances supported isolation- by-distance for the S7, but not for the CR, suggesting a complex scenario for the history of the rusty blenny in the Mediterranean Sea. The pattern of genetic structure displayed by P. sanguinolentus could be explained as the result of a post-glacial colonization of the Atlantic coast of Europe from the Mediterranean Sea.

2017Journal article

Restricted access