Assemblage structure and secondary production of mesozooplankton in shallow water volcanic CO2 vents of the Azores

Dissertação de mestrado, Biologia Marinha, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015

Semi-pelagic longline selectivity for two demersal species from the Azores: the black spot sea bream (Pagellus bogaraveo) and the bluemouth rockfish (Helicolenus dactylopterus dactylopterus)

The selectivity of four hook sizes (STELL brand(1), Quality 2335, numbers 12, 9, 6 and 4) used in a semi-pelagic longline fishery was studied in the Azores. Two species were caught in sufficient numbers for modelling of selectivity: the black spot sea bream (Pagellus bogaraveo) and the bluemouth rockfish (Helicolenus dactylopterus dactylopterus). A maximum likelihood method was used to fit a versatile model which can be used to describe a wide range of selectivity curves; from bell-shaped to asymptotic. Significant differences in size selectivity between hooks were found for both species. In the case of Pagellus bogaraveo, the smallest hook (number 12) had the lowest catch rates and all hooks were characterised by logistic-type selectivity curves, with sizes at 50% selectivity of: 27.9, 30.4, and 32.8 cm for hooks numbers 12, 9 and 6, respectively. The number 9 hook was the most efficient for Helicolenus d. dactylopterus, with selectivity curves varying from strongly skewed to the right for the number 12 hook to logistic-type for the numbers 6 and 4 hooks. Sizes at 50% selectivity for this species were 16.8, 18.7, 20.7, and 22.0 cm. respectively. (C) 1999 Elsevier Science B.V. All rights reserved.

Age and growth of bluemouth, Helicolenus dactylopterus (Delaroche, 1809) from the Azores

The age and growth of the Helicolenus dactylopterus (Delaroche, 1809) in the Azorean waters were studied using whole and sliced otolith readings. Individuals were collected during demersal surveys carried out around the Azores islands and its most important fishing banks and also from commercial landings. A total of 1024 individuals were measured, weighed and their sex was determined. Individuals ranged from 3 to 49 cm total length (TL) and their estimated ages between 0 and 32 years old. The otoliths showed the typical teleost fish pattern with alternated opaque and hyaline rings. Significant differences between sliced and whole otolith readings were found, especially after 7 years old (>25 cm TL). Sliced otoliths were found easier to read, regardless of TL or age. Comparisons with other studies for the Azores region and other areas are discussed.

Stochastic ground motion simulation with geological site effects in damage asessment

Damage assessment of structures with a mechanical non linear model demands the representation of seismic action in terms of an accelerogram (dynamic analysis) or a response spectrum (pushover analysis). Stochastic ground motion simulation is largely used in regions where seismic strong-motion records are available in insufficient number. In this work we present a variation of the stochastic finite-fault method with dynamic corner frequency that includes the geological site effects. The method was implemented in a computer program named SIMULSIS that generate time series (accelerograms) and response spectra. The program was tested with the MW= 7.3 Landers earthquake (June 28, 1992) and managed to reproduce its effects. In the present work we used it to reproduce the effects of the 1980’s Azores earthquake (January 1, 1980) in several islands, with different possible local site conditions. In those places, the response spectra are presented and compared with the buildings damage observed.

Technical and economic viability of traps in the portuguese fishery of deepwater rose shrimp (Parapenaeus longirostris)

Dissertação de mestrado, Aquacultura e Pescas, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015

Phylogeographical history of the white seabream Diplodus sargus (Sparidae): Implications for insularity

Partial sequences of the mitochondrial control region and its comparison with previously published cytochrome b (cyt-b) and microsatellite data were used to investigate the influence of island isolation and connectivity on white seabream genetic structure. To achieve this, a total of 188 individuals from four island localities (Castellamare and Mallorca, Mediterranean Sea; Azores and Canary Islands, Atlantic Ocean) and five coastal localities (Banyuls, Murcia and Tunisia, Mediterranean Sea; Galicia and Faro, Atlantic Ocean) were analysed. Results showed high haplotype diversity and low to moderate nucleotide diversity in all populations (except for the Canary Islands). This pattern of genetic diversity is attributed to a recent population expansion which is corroborated by other results such as cyt-b network and demographic analyses. Low differentiation among Mediterranean/Atlantic and coastal/island groups was shown by the AMOVA and FST values, although a weak phylogeographic break was detected using cyt-b data. However, we found a clear and significant island/ distance effect with regard to the Azores islands. Significant genetic differentiation has been detected between the Azores islands and all other populations. The large geographical distance between the European continental slope and the Azores islands is a barrier to gene flow within this region and historic events such as glaciation could also explain this genetic differentiation.

Phylogeography of the Atlanto-Mediterranean sea cucumber Holothuria (Holothuria) mammata: the combined effects of historical processes and current oceanographical pattern

We assessed the genetic structure of populations of the widely distributed sea cucumber Holothuria (Holothuria) mammata Grube, 1840, and investigated the effects of marine barriers to gene flow and historical processes. Several potential genetic breaks were considered, which would separate the Atlantic and Mediterranean basins, the isolated Macaronesian Islands from the other locations analysed, and the Western Mediterranean and Aegean Sea (Eastern Mediterranean). We analysed mitochondrial 16S and COI gene sequences from 177 individuals from four Atlantic locations and four Mediterranean locations. Haplotype diversity was high (H = 0.9307 for 16S and 0.9203 for COI), and the haplotypes were closely related (p = 0.0058 for 16S and 0.0071 for COI). The lowest genetic diversities were found in the Aegean Sea population. Our results showed that the COI gene was more variable and more useful for the detection of population structure than the 16S gene. The distribution of mtDNA haplotypes, the pairwise FST values and the results of exact tests and AMOVA revealed: (i) a significant genetic break between the population in the Aegean Sea and those in the other locations, as supported by both mitochondrial genes, and (ii) weak differentiation of the Canary and Azores Islands from the other populations; however, the populations from the Macaronesian Islands, Algarve and West Mediterranean could be considered to be a panmictic metapopulation. Isolation by distance was not identified in H. (H.) mammata. Historical events behind the observed findings, together with the current oceanographic patterns, were proposed and discussed as the main factors that determine the population structure and genetic signature of H. (H.) mammata

Connectivity patterns inferred from the genetic structure of white seabream (Diplodus sargus L.)

Themarine environment seems, at first sight, to be a homogeneousmediumlacking barriers to species dispersal. Nevertheless, populations of marine species show varying levels of gene flow and population differentiation, so barriers to gene flow can often be detected. Weaimto elucidate the role of oceanographical factors ingenerating connectivity among populations shaping the phylogeographical patterns in the marine realm, which is not only a topic of considerable interest for understanding the evolution ofmarine biodiversity but also formanagement and conservation of marine life. For this proposal,we investigate the genetic structure and connectivity between continental and insular populations ofwhite seabreamin North East Atlantic (NEA) and Mediterranean Sea (MS) aswell as the influence of historical and contemporary factors in this scenario using mitochondrial (cytochrome b) and nuclear (a set of 9 microsatellite) molecular markers. Azores population appeared genetically differentiated in a single cluster using Structure analysis. This result was corroborated by Principal Component Analysis (PCA) and Monmonier algorithm which suggested a boundary to gene flow, isolating this locality. Azorean population also shows the highest significant values of FST and genetic distances for both molecular markers (microsatellites and mtDNA). We suggest that the breakdown of effective genetic exchange between Azores and the others' samples could be explained simultaneously by hydrographic (deep water) and hydrodynamic (isolating current regimes) factors acting as barriers to the free dispersal of white seabream(adults and larvae) and by historical factors which could be favoured for the survival of Azorean white seabream population at the last glaciation. Mediterranean islands show similar genetic diversity to the neighbouring continental samples and nonsignificant genetic differences. Proximity to continental coasts and the current system could promote an optimal larval dispersion among Mediterranean islands (Mallorca and Castellamare) and coasts with high gene flow.

Broad-scale mapping of seafloor habitats in the north-east Atlantic using existing environmental data

If marine management policies and actions are to achieve long-term sustainable use and management of the marine environment and its resources, they need to be informed by data giving the spatial distribution of seafloor habitats over large areas. Broad-scale seafloor habitat mapping is an approachwhich has the benefit of producing maps covering large extents at a reasonable cost. This approach was first investigated by Roff et al. (2003), who, acknowledging that benthic communities are strongly influenced by the physical characteristics of the seafloor, proposed overlaying mapped physical variables using a geographic information system (GIS) to produce an integrated map of the physical characteristics of the seafloor. In Europe the method was adapted to the marine section of the EUNIS (European Nature Information System) classification of habitat types under the MESH project, andwas applied at an operational level in 2011 under the EUSeaMap project. The present study compiled GIS layers for fundamental physical parameters in the northeast Atlantic, including (i) bathymetry, (ii) substrate type, (iii) light penetration depth and (iv) exposure to near-seafloor currents andwave action. Based on analyses of biological occurrences, significant thresholds were fine-tuned for each of the abiotic layers and later used in multi-criteria raster algebra for the integration of the layers into a seafloor habitat map. The final result was a harmonised broad-scale seafloor habitat map with a 250 m pixel size covering four extensive areas, i.e. Ireland, the Bay of Biscay, the Iberian Peninsula and the Azores. The map provided the first comprehensive perception of habitat spatial distribution for the Iberian Peninsula and the Azores, and fed into the initiative for a pan- European map initiated by the EUSeaMap project for Baltic, North, Celtic and Mediterranean seas.