Cymodocea nodosa, a marine angiosperm, an ecosystem engineer in the Mediterranean Sea and the Northwest Atlantic Ocean; however, as in other seagrasses meadows worldwide, the swards are actually declining due to increasing human pressures. Hence, we have developed an effective propagation methodology that provides C. nodosa seedlings for seagrass meadow restoration and conservation. This method consists of: i) germination of wild-collected seeds under hyposaline conditions, ii) acclimation of germinated seedling in tanks (1.6 m 3) until there are two shoots per seedling (;30 days), and iii) transplantation of acclimated seedlings to the field in dense groups. Our field outplants withstood herbivore activity and physical disturbance during the winter season, and propagated vegetatively, resulting in the spread and establishment of a new patch that has persisted for nine months.

No abstract

Exploited, understudied populations of the common octopus, Octopus vulgaris Cuvier, 1797, occur in the northeastern Atlantic (NEA) throughout Macaronesia, comprising the Azores, Madeira and Canaries, and also the Cabo Verde archipelago. This octopus species, found from the intertidal to shallow continental-shelf waters, is largely sedentary, and the subject of intense, frequently unregulated fishing effort. We infer connectivity among insular populations of this octopus. Mitochondrial control region and COX1 sequence datasets reveal two highly divergent haplogroups (α and β) at similar frequencies, with opposing clinal distributions along the sampled latitudinal range. Haplogroups have different demographic and phylogeographic patterns, with origins related to the two last glacial maxima. F ST values suggest a significant differentiation for most pairwise comparisons, including insular and continental samples, from the Galicia and Morocco coasts, with the exception of pairwise comparisons for samples from Madeira and the Canaries populations. Results indicate the existence of genetically differentiated octopus populations throughout the NEA. This emphasizes the importance of regulations by autonomous regional governments of the Azores, Madeira and the Canaries, for appropriate management of insular octopus stocks.

The Azorean barnacle, Megabalanus azoricus (Pilsbry, 1916), is a Macaronesian endemic whose obscure taxonomy and the unknown relationships among forms inhabiting isolated Northern Atlantic oceanic islands is investigated by means of molecular analysis herein. Mitochondrial data from the 16S rRNA and COX1 genes support its current species status, tropical ancestry, and the taxonomic homogeneity throughout its distribution range. In contrast, at the intraspecific level and based on control region sequences, we detected an overall low level of genetic diversity and three divergent lineages. The haplogroups α and γ were sampled in the Azores, Madeira, Canary, and Cabo Verde archipelagos; whereas haplogroup β was absent from Cabo Verde. Consequently, population analysis suggested a differentiation of the Cabo Verde population with respect to the genetically homogenous northern archipelagos generated by current oceanographic barriers. Furthermore, haplogroup α, β, and γ demographic expansions occurred during the interglacial periods MIS5 (130 Kya - thousands years ago -), MIS3 (60 Kya), and MIS7 (240 Kya), respectively. The evolutionary origin of these lineages is related to its survival in the stable southern refugia and its demographic expansion dynamics are associated with the glacial-interglacial cycles. This phylogeographic pattern suggests the occurrence of genetic discontinuity informative to the delimitation of an informally defined biogeographic entity, Macaronesia, and its generation by processes that delineate genetic diversity of marine taxa in this area.

The taxonomy of pedunculate cirripedes belonging to the genus Pollicipes has essentially remained unchanged since Charles Darwin described them in his exhaustive work on the Cirripedia. This genus includes three species of stalked barnacles: Pollicipes pollicipes in the north-eastern Atlantic, P. polymerus in the north-eastern Pacific and P. elegans in the central-eastern Pacific. However, a population genetics analysis of P. pollicipes suggested the presence of a putative cryptic species collected from the Cape Verde Islands in the central-eastern Atlantic. This study examines the morphology of these genetically divergent specimens and compares them with that of representative Atlantic samples of the biogeographically closely related P. pollicipes and with the poorly described P. elegans. Molecular data, including mitochondrial COX1 and nuclear ribosomal interspaces sequences, were obtained for all species of the genus Pollicipes. Morphological distinctiveness, diagnostic characters, congruent divergence level and monophyletic clustering, at both nuclear and mitochondrial loci support the taxonomic status of this new species, Pollicipes darwini.

Summary: Seagrass meadows perform essential ecosystem functions and services. Though the meadows are globally deteriorating, numerous regressions remain unreported as a result of data fragmentation. Cymodocea nodosa is the most important seagrass in shallow coastal waters of the Canary Islands. No study has so far investigated temporal population trends at the entire archipelago scale. Using data collected in the past 23 years by local companies, public authorities and research groups, the population trends of Cymodocea nodosa were analysed over the past two decades at the scales of islands, island sectors and meadows. During this period, a prevalence of negative trends was revealed for three seagrass demographic descriptors (seagrass shoot density, coverage and leaf length) at the three scales, evidencing an overall deterioration in seagrass meadow integrity. These results suggest the need to develop correct management strategies to guarantee the conservation of this seagrass and the meadows it creates.Keywords: seagrass; population trend; temporal patterns; change rates; Canary Islands; Atlantic Ocean. Tendencias de la fanerógama marina Cymodocea nodosa (Magnoliophyta) en las Islas Canarias: cambios poblacionales en las dos últimas décadasResumen: Las praderas de fanerógamas marinas suministran funciones y servicios esenciales para los ecosistemas. A pesar de que dichas praderas están globalmente deteriorándose, numerosas regresiones son aún desconocidas como resultado de la falta de datos. Cymodocea nodosa es la fanerógama marina más importante en aguas someras de las costas del Archipié-lago Canario. No obstante, ningún estudio ha analizado las tendencias temporales de sus poblaciones a escala de todo el archipiélago. Utilizando datos recogidos durante los últimos 23 años por empresas, administraciones públicas y grupos de investigación, se analizaron las tendencias de las poblaciones de Cymodocea nodosa durante las últimas dos décadas en el Archipiélago Canario a la escala de islas, sectores insulares y praderas individuales. A lo largo de este periodo, se observa una prevalencia de tendencias negativas para tres descriptores demográficos (densidad de haces, cobertura y longitud de hoja), evidenciando un deterioro general en la integridad de las praderas. Estos resultados sugieren la necesidad de desarrollar estrategias de gestión correctas para garantizar la conservación de las praderas constituidas por esta planta marina.Palabras clave: fanerógamas marinas; tendencia poblacional; patrones temporales; tasa de cambio; islas Canarias; Océano Atlántico.Citation/Como citar este artículo: Fabbri F., Espino F., Herrera R., Moro L., Haroun R., Riera R., González-Henriquez N., Bergasa O., Monterroso O., Ruiz de la Rosa M., Tuya F. 2015. Trends of the seagrass Cymodocea nodosa (Magnoliophyta) in the Canary Islands: population changes in the last two decades. Sci. Mar. 79(1): 7-13. doi: http://dx.doi.org/10.3989/ scimar.04165.19BEditor: E. Ballesteros.

Individuals of mussels were collected in ponds from a commercial shrimp farm in the Unare region, Anzoátegui State, Venezuela. Identification was carried out using dichotomous keys and corroborated via analysis of similarities between the sequences of partial mitochondrial DNA of the cytochrome oxidase gene and Mytella strigata (Hanley, 1843) reported in GenBank with 99-100% similarity. Morphological analyses further supported the identification of the specimen. The first report of M. strigata in the Venezuelan Caribbean coast suggests that it could be a transplanted species. Possible negative effects of M. strigata on commercial shrimp production systems are discussed.

The adoption of measures to protect the viability of threatened populations should be supported by empirical data identifying appropriate conservation units and management strategies. The global population of the majorera limpet, P. candei candei d’Orbigny, 1840, is restricted to the Macaronesian islands in the NE Atlantic, including near-to-extinct and healthy populations in Fuerteventura and Selvagens, respectively. The taxonomic position, genetic diversity and intra- and interspecific relationships of these populations are unclear, which is hindering the implementation of a recovery plan for the overexploited majorera limpet on Fuerteventura. In this study, ddRAD-based genome scanning was used to overcome the limitations of mitochondrial DNA-based analysis. As a result, P. candei candei was genetically differentiated from the closely related P. candei crenata for the first time. Moreover, genetic differentiation was detected between P. candei candei samples from Selvagens and Fuerteventura, indicating that translocations from the healthy Selvagens source population are inadvisable. In conclusion, the majorera limpet requires population-specific management focused on the preservation of exceptional genetic diversity with which to face future environmental challenges.