14 documents found, page 1 of 2
A multimetric approach to evaluate offshore mussel aquaculture effects on the t...
Lacson, A. Z.; Piló, David; Pereira, F.; Carvalho, A. N.; Curdia, J.; Caetano, M.; Drago, T.; Santos, M. N.; Gaspar, MiguelA multimetric approach was used to detect structural, compositional, and functional shifts in the underlying macrobenthic communities of an offshore mussel (Mytilus galloprovincialis) farm in a Portuguese Aquaculture Production Area. Sampling stations distributed inside and outside this area were used to evaluate sediment descriptors and macrobenthic samples collected before (April and September 2010) and after...
Temporal variability in epifaunal assemblages associated with temperate gorgoni...
Dias, I. M.; Cúrdia, J.; Cunha, M. R.; Santos, M. N.; Carvalho, S.The present study is one of the few that investigate the temporal variability of epifaunal assemblages associated with coral species, particularly the octocorals Eunicella gazella and Leptogorgia lusitanica in south Portugal. The results suggest time rather than colony size as a primary driver of the ecological patterns of these assemblages, which were dominated by amphipods, molluscs and polychaetes. Temporal ...
Biodiversity patterns of epifaunal assemblages associated with the gorgonians E...
Carvalho, S.; Cúrdia, J.; Pereira, F.; Guerra-García, J. M.; Santos, M. N.; Cunha, M. R.Patterns of biodiversity (α- and β-diversity), abundance and community structure of the epifaunal assemblages associated with two gorgonians, Eunicella gazella and Leptogorgia lusitanica, were analysed in relation to host, colony size, location and time. Colony size and time were the major factors shaping attendant assemblages. Patterns of α-diversity and β-diversity were host-dependent. Assemblages associated ...
Residency, movements and habitat use of adult white seabream (Diplodus sargus) ...
Abecasis, D.; Bentes, L.; Lino, P. G.; Santos, M. N.; Erzini, KarimArtificial reefs are used as management tools for coastal fisheries and ecosystems and the knowledge of habitat use and fish movements around them is necessary to understand their performance and improve their design and location. In this study wild specimens of Diplodus sargus were tagged with acoustic tags and their movements were tracked using passive acoustic telemetry. The monitored area enclosed a natural...
The effect of depth and sediment type on the spatial distribution of shallow so...
Carvalho, Susana; Cunha, Marina R.; Pereira, Fábio; Pousao-Ferreira, P.; Santos, M. N.; Gaspar, M. B.The present study provides updated information on amphipod assemblages of the southern Portuguese coast, the most south-western part of continental Europe. The influence of depth and sediment type on the spatial distribution of shallow soft-bottom amphipods was tested by means of univariate and multivariate methods. Samples were collected down to 40 m depth within areas ranging from very fine sand to gravel. Th...
Diplodus spp. assemblages on artificial reefs: importance for near shore fisheries
Azevedo Leitão, F. Marina; Santos, M. N.; Erzini, Karim; Monteiro, C. C.Artificial reefs have been deployed along the southern coast of Portugal (Algarve) since 1990 to enhance artisanal fisheries. The objectives of this study were to: (1) describe the colonisation process; (2) assess the role of the artificial reefs in terms of juvenile recruitment and growth and as mating/spawning areas and (3) evaluate the potential of artificial reefs as near shore artisanal fishing grounds for...
Size selectivity of the Spisula solida dredge in relation to tooth spacing and ...
Gaspar, Miguel; Miguel de Sousa Leitão, Francisco; Santos, M. N.; Sobral, M.; Chícharo, Luís; Chicharo, Maria Alexandra Teodosio; Monteiro, C. C.A study was undertaken on the northwestern coast of Portugal to evaluate the selectivity effect of both tooth spacing and mesh size on the catch of the white clam (Spisula solida). Two typical clam dredges, equipped with different tooth spacing and mesh size, were towed side by side. Three tooth spacing (20, 40 and 60 mm) and three mesh sizes (35, 40 and 50 mm) were investigated. The dredge selectivity experime...
A comparison of direct macrofaunal mortality using three types of clam dredges
Gaspar, Miguel; Miguel de Sousa Leitão, Francisco; Santos, M. N.; Chícharo, Luís; Dias, M. D.; Chícharo, Alexandra; Monteiro, C. C.The white clam Spisula solida is harvested along the entire coast of Portugal using mechanical dredges. In this study, the total direct mortality of the macrobenthic community caused by three types of clam dredges (north dredge—ND, traditional dredge—TD, and the metallic grid dredge—GD) used in the S. solida fishery was determined and compared. The relationship between mortality and catching efficiency for each...
Recovery of substrates and macro-benthos after fishing trials with a new Portug...
Gaspar, Miguel; Santos, M. N.; Miguel de Sousa Leitão, Francisco; Chícharo, Luís; Chicharo, Maria Alexandra Teodosio; Monteiro, C. C.The effect of dredging on bottom structure was assessed, to estimate the damage inflicted on the benthic macrofauna left on the dredge path and to evaluate aggregations of scavengers within the track. Sediment suspended during dredging rapidly resettled both on sand and sandy-mud bottoms. Dredge tracks were deeper on sandy-mud sediments and persisted longer than in sandy sediments. The disappearance of tracks i...
Influence of mesh size and tooth spacing on the proportion of damaged organisms...
Gaspar, Miguel; Miguel de Sousa Leitão, Francisco; Santos, M. N.; Sobral, M.; Chícharo, Luís; Chicharo, Maria Alexandra Teodosio; Monteiro, C. C.Experiments to assess the effect of mesh size and tooth spacing on the catch of Spisula solida were undertaken with the aim of determining an optimal combination of these two characteristics to minimize the dredging impact on by-catch species. However, our data showed that tooth spacing, mesh size and the interactions between these two factors did not affect the number of damaged macrofaunal individual’s caught...