First record of Ligia oceanica (Linnaeus, 1767) (Isopoda: Ligiidae) in the Canary Islands

This study presents the first record of L. oceanica in the Canary Islands. Additionally, body features between L. oceanica and Ligia italica Fabricius, 1798, the other sea-slater inhabiting the Archipelago, were compared

Effects of granulometric gradient on macrofaunal assemblages in Los Cristianos harbour (Tenerife, Canary Islands)

Along the rapid increase of coastal tourism worldwide, evidence is accumulating on the numerous environmental coastal impacts that it causes on marine environments. One of the most important anthropogenic pressures is the construction of marinas or recreational harbours. Typically, most of the studies provide snapshots of the spatial distribution of macrobenthic communities inside and outside of the marina area. However, there is no much information about sedimentary dynamics inside the harbour and their effect on macroinfaunal In the innermost stations of Los Cristianos harbour a different macrofaunal community was present, dominated by the amphipods Cheirocratus assimilis and Corophium acutum and the polychaete Nainereis laevigata. Changes in macrofaunal assemblages could be used as early warnings in identifying environmental impacts before they cause major shifts in the marine environment

Subtidal soft-bottom macroinvertebrate communities of the Canary Islands. An ecological approach

O arquipélago das Canárias é caracterizado por um mosaico de fundos inconsolidados contendo bancos de Cymodocea nodosa, Caulerpa spp., fundos calcários, bancos de sabelídeos e sedimento não biogênico, que abrigam diferentes comunidades da macrofauna. Ambientes vegetados (Cymodocea e Caulerpa) possuem comunidades mais diversificadas quando comparados aos ambientes de fundos não vegetados. Os resultados do presente estudo indicaram que os bancos de Caulerpa, primeiramente, e em seguida os bancos de Cymodocea nodosa e de sabelídeos, formam os sistemas mais ricos e diversificados da área. Além disso, puderam também ser detectadas diferenças de biodiversidade entre as ilhas do arquipélago, sendo os valores mais altos localizados nas ilhas ao leste (Lanzarote e Gran Canaria) e os menores nas ilhas à oeste (La Palma).The Canarian archipelago is characterized by a mosaic of soft-bottoms such as Cymodocea nodosa meadows, Caulerpa spp. meadows, mäerl bottoms, sabellid fields and bare sandy seabeds, including various macroinfaunal communities. Vegetated habitats (e.g. Cymodocea and Caulerpa) maintain more diverse communities than the non-vegetated seabeds. The results indicated that Caulerpa meadows and, to a lesser extent, Cymodocea nodosa and sabellid fields are the richest and most diverse ecosystems in the study area. Moreover, biodiversity differences among islands could be detected with maximum values on the eastern islands (Lanzarote and Gran Canaria) and lowest values on the western ones (La Palma)

Unravelling the effects of exploitation on the size–structure of the intertidal topshell Phorcus sauciatus in harvested and non-harvested Atlantic regions

Intertidal molluscs are keystone species often used as biological indicators of human-driven pertur bations. The increasing levels of harvesting pressure on these intertidal grazers, due to the expansion of human population on coastal areas, is known to affect negatively the exploited populations by altering population size–structure and decreasing abundances. A comparative study on the effect of harvest on the size–structure of Phorcus sauciatus populations was conducted according to the exploitation level, harvested and non-harvested, throughout the intertidal zone of mainland Portugal, Azores, Madeira, and the Canaries. The comparative analysis of the size–structure of 10,480 individuals of P. sauciatus showed that the largest individuals were recorded in the Azores and the smallest in Madeira. In harvested populations, P. sauciatus showed to be under greater harvesting pressure in the archipelago of Madeira, where the lowest mean size was observed. In the Canaries the harvesting is regulated whilst in the mainland Portugal the regulation is scarce. The Azores showed no harvesting pressure. Marine Protected Areas showed individuals with the highest mean sizes supporting their effectiveness in preserving the size–structure of this species, regardless the ecoregion and thus, the harvesting pressure. The present results highlight the importance of harvesting regulation of P. sauciatus in Madeira, as well as the implementation of management measures aiming at the sustainable exploitation and conservation of this species.info:eu-repo/semantics/publishedVersio

Weight–length relationships of four intertidal mollusc species from the northeastern Atlantic Ocean and their potential for conservation

Weight-length relationships (WLRs) are frequently used for the development of comparative studies of life history, population dynamics, ecosystem modelling and estimation of the production and biomass of populations among regions. WLRs provide information about growth, wellbeing and fitness of a population in a marine environment. WLRs for four topshells (Phorcus atratus, Phorcus lineatus, Phorcus mariae, Phorcus sauciatus) caught in North-eastern Atlantic Ocean (Azores, Canaries, Cape Verde, Madeira and Mainland Portugal) were established and their relative growth was assessed. The results showed that almost all species exhibited a positive allometric growth. A comparative study on the effect of harvest in the relative growth of P. sauciatus in the archipelago of Madeira showed that all the populations from exploited areas exhibited a negative allometric growth in contrast to the populations from the Marine Protected Areas (MPAs) which were predominantly isometric. The present results indicate that the conservation measures established in the protected areas promoted a positive effect in the protected populations and are valuable for establishing a set of monitoring and management measures aiming at the sustainable exploitation and conservation of these species. These results are important to demonstrate the role of MPAs in the conservation of these keystone species in the north eastern Atlantic Ocean rocky shore ecosystems.info:eu-repo/semantics/publishedVersio

Paragnathia formica (Hesse, 1864) (Isopoda: Gnathiidae) a new record to the Canary archipelago

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Check-list of interstitial polychaetes from intertidal and shallow subtidal soft bottoms of Tenerife, Canary Islands

A check-list of polychaete species from two stations on the south coast of Tenerife (Los Abrigos and Los Cristianos) at two different tidal levels, intertidal and shallow subtidal (3 m depth) is presented. A total of 47 species were collected, the hesionid Microphthalmus pseudoaberrans Campoy & Viéitez, 1982 and the spionids Rhynchospio glutaea (Ehlers, 1897) and Spio filicornis (O.F. Müller, 1776) being the most abundant. With 18 species the family Syllidae is the most diverse, followed by the Spionidae and Paraonidae with 6 and 5 species, respectively. The interstitial polychaetes found are represented by both meiofaunalsized and small-sized macrofaunal species

Three new records of Desmodorids (Nematoda, Desmodoridae) from sandy seabeds of the Canary islands

In an ecological study of meiofaunal assemblages in two locations (Los Abrigos and Los Cristianos) of Tenerife (Canary Islands, NE Atlantic Ocean), several desmodorid species were found throughout the study period. Three species belonging to the family Desmodoridae were collected in intertidal and shallow subtidal sandy seabeds. These species were Desmodorella aff. tenuispiculum Allgen, 1928, Metachromadora sp. and Spirinia parasitifera Bastian, 1865. Descriptions, figures and tables with meristic data are presented. Moreover, differences between canarian and specimens from other geographical regions were discussed.Durante la realización de un estudio ecológico de las comunidades meiofaunales en dos localidades de muestreo (Los Abrigos y Los Cristianos) de la isla de Tenerife (Islas Canarias, Océano Atántico), varios ejemplares de desmodóridos fueron recolectados. Tres especies pertenecientes a la familia Desmodoridae fueron encontradas en fondos arenosos intermareales y submareales someros. Estas tres especies fueron: Desmodorella aff. tenuispiculum Allgen, 1928, Metachromadora sp. y Spirinia parasitifera Bastian, 1865. Se presentan descripciones, figuras y tablas con datos merísticos de estas especies. Además, se detallan las diferencias encontradas entre los ejemplares canarios y los procedentes de otras áreas geográficas

Temporal Variations of Shallow Subtidal Meiofauna in Los Cristianos Bay (Tenerife, Canary Islands, Ne Atlantic Ocean)

As assembleias da meiofauna de Los Cristianos Bay, Tenerife, Ilhas Canárias, foi amostrada de maio de 2000 a abril de 2001 a 3 m de profundidade. Nematoda dominou durante todo o período de estudo, variando entre 84.52% em maio de 2000 a 95.93% em outubro do mesmo ano. Copepoda e Polychaeta foram o segundo e terceiro grupos mais abundantes, respectivamente. A densidade apresentou diferenças significativas ao longo do período, com valores mínimos na primavera-verão (maio-julho) e máximos no inverno (janeiro e fevereiro). Essa sazonalidade está sendo atribuída principalmente às variações temporais das espécies mais abundantes de nemátodes (Daptonema hirsutum e Pomponema sedecima). A meiofauna apresentou ainda diferenças na composição e abundância em maio e junho de 2000 quando comparado com os meses restantes do estudo. As variáveis ambientais explicaram parcialmente as variações na estrutura da comunidade e o tipo sedimentar areia muito fina destacou-se entre os mais importantes, juntamente com outras variáveis, tais como nitrogênio e conteúdo de matéria orgânica.A subtidal meiofaunal assemblage in Los Cristianos Bay, Tenerife, Canary Islands was sampled from May 2000 to April 2001, at 3 m depth. Nematodes dominated overwhelmingly during the study period, ranging from 84.52% in May 2000 to 95.93% in October 2000. Copepods and polychaetes were the second and the third most abundant groups, respectively. Meiofaunal densities showed significant differences throughout the study period, with minimum abundances during the spring-summer months (May-July) and highest densities in winter (January and February). This seasonality is mainly due to the temporal variations of the most abundant species (nematodes Daptonema hirsutum and Pomponema sedecima), with differences in meiofauna species composition and abundance during May and June 2000 as compared to the remaining months of the study period. Environmental variables partly explained meiofaunal community structure, being the sedimentary type of very fine sands the most important, jointly with other variables, such as nitrogen and organic matter content