Variability of Iberian upwelling implied by ERA-40 and ERA-Interim reanalyses

The Regional Ocean Modeling System ocean model is used to simulate the decadal evolution of the regional waters in offshore Iberia in response to atmospheric fields given by ECMWF ERA-40 (1961–2001) and ERA-Interim (1989–2008) reanalyses. The simulated sea surface temperature (SST) fields are verified against satellite AVHRR SST, and they are analysed to characterise the variability and trends of coastal upwelling in the region. Opposing trends in upwelling frequency are found at the northern limit, where upwelling has been decreasing in recent decades, and at its southern edge, where there is some evidence of increased upwelling. These results confirm previous observational studies and, more importantly, indicate that observed SST trends are not only due to changes in radiative or atmospheric heat fluxes alone but also due to changes in upwelling dynamics, suggesting that such a process may be relevant in climate change scenarios

A study of Docetaxel-induced effects in MCF-7 cells by means of Raman microspectroscopy

Chemotherapies feature a low success rate of about 25%, and therefore, the choice of the most effective cytostatic drug for the individual patient and monitoring the efficiency of an ongoing chemotherapy are important steps towards personalized therapy. Thereby, an objective method able to differentiate between treated and untreated cancer cells would be essential. In this study, we provide molecular insights into Docetaxel-induced effects in MCF-7 cells, as a model system for adenocarcinoma, by means of Raman microspectroscopy combined with powerful chemometric methods. The analysis of the Raman data is divided into two steps. In the first part, the morphology of cell organelles, e.g. the cell nucleus has been visualized by analysing the Raman spectra with k-means cluster analysis and artificial neural networks and compared to the histopathologic gold standard method hematoxylin and eosin staining. This comparison showed that Raman microscopy is capable of displaying the cell morphology; however, this is in contrast to hematoxylin and eosin staining label free and can therefore be applied potentially in vivo. Because Docetaxel is a drug acting within the cell nucleus, Raman spectra originating from the cell nucleus region were further investigated in a next step. Thereby we were able to differentiate treated from untreated MCF-7 cells and to quantify the cell–drug response by utilizing linear discriminant analysis models

Evidence for rangewide panmixia despite multiple barriers to dispersal in a marine mussel

Oceanographic features shape the distributional and genetic patterns of marine species by interrupting or promoting connections among populations. Although general patterns commonly arise, distributional ranges and genetic structure are species-specific and do not always comply with the expected trends. By applying a multimarker genetic approach combined with Lagrangian particle simulations (LPS) we tested the hypothesis that oceanographic features along northeastern Atlantic and Mediterranean shores influence dispersal potential and genetic structure of the intertidal mussel Perna perna. Additionally, by performing environmental niche modelling we assessed the potential and realized niche of P. perna along its entire native distributional range and the environmental factors that best explain its realized distribution. Perna perna showed evidence of panmixia across > 4,000 km despite several oceanographic breaking points detected by LPS. This is probably the result of a combination of life history traits, continuous habitat availability and stepping-stone dynamics. Moreover, the niche modelling framework depicted minimum sea surface temperatures (SST) as the major factor shaping P. perna distributional range limits along its native areas. Forthcoming warming SST is expected to further change these limits and allow the species to expand its range polewards though this may be accompanied by retreat from warmer areas.Fundacao para a Ciencia e Tecnologia (FCT-MEC, Portugal) [UID/Multi/04326/2013, IF/01413/2014/CP1217/CT0004]; South African Research Chairs Initiative (SARChI) of the Department of Science and Technology; National Research Foundation; South African National Research Foundation (NRF); Portuguese Fundacao para a Ciencia e Tecnologia (FCT) [SFRH/BPD/85040/2012, SFRH/BPD/111003/2015]info:eu-repo/semantics/publishedVersio

Bio-physical coupling around three shallow seamounts in the South Western Indian Ocean, with regional comparisons based on modelling, remote sensing and observational studies

Based on satellite and in situ data, the dynamic characteristics and vertical structure of a surface intensified mesoscale eddy dipole recently expelled from the South East Madagascar Current (SEMC) is described for the first time. The dipole was surveyed 250 nautical miles south of Madagascar between 14 and 23 November 2016, during west-east and south-north transects carried out over the northern Madagascar Ridge. The dipole consisted of two counter-rotating vortices of similar size (100 km) and intensity (0.7 f), and an intense southwestward jet (150 cm s(-1)) in the frontal region between the two eddies. The cyclonic eddy was lying on the western side of the anticyclonic eddy. With azimuthal velocities reaching 100 cm s(-1) at the surface and decreasing slowly with depth (40 cm s(-1) at -600 m), this dipole was defined as a highly non-linear (Ro similar to 0.7) isolated eddy-type structure (c(beta) similar to 11 cm s(-1) and U/c(beta) similar to 0.7) capable of trapping and advecting water masses over large distances. The enhanced concentration of chlorophyll-a found in the cyclone relative to the anticyclone could be tracked back to the spin-up phase of the two eddies and attributed to eddy-pumping. The eddy cores were located above the pycnocline (1026.4 kg m(-3)), within the upper 600 m, and consisted of varieties of Subtropical Underwater (STUW) found within the SEMC. The STUW found in the anticyclone was more saline and oxygenated than in the cyclone, highlighting mixing with the inshore shelf waters from the southeastern coastal upwelling cell off Madagascar. Observations suggest that the dipole interacted strongly with the chaotic bathymetry of the region, characterized by a group of five seamounts lying between -240 m and -1200 m. The bathymetry blocked its westward advection, trapping it in the vicinity of one shallow seamount for more than 4 weeks, so enhancing the role of the eddy-induced velocities in stirring the surrounding water masses. Squeezed between the southern Madagascan shelf and the northern flank of the anticyclone, two filament-like dynamic features with very different water-mass properties could be observed on the south-north transect: i) one filament highly concentrated in chlorophyll-a demonstrating the capacity of the eddy to export shelf water offshore; ii) intrusions of southern-type STUW generally found south of the South Indian Counter Current (SICC) recirculating on the external flanks of the anticyclone. Although the observed circulation and hydmgraphy were largely constrained by the presence of the mesoscale eddy dipole, unmistakable fine-scale dynamics were also observed in the vicinity of the MAD-Ridge seamount, superimposed onto the mesoscale eddy flow

International conference ICAWA 2016 : extended book of abstract : the AWA project : ecosystem approach to the management of fisheries and the marine environment in West African waters

Over the last decades, small pelagic fisheries have shown an increasing development in Senegal, especially those targeting Sardinella aurita and S. maderensis. Their landing and fishing effort quickly increase for both species, from less than 100,000 tons with 35,035 trips in the early 80's to a peak of over 400,000 tons with 86,427 trips in 2008. The Senegalese small scale pelagic fisheries, targeting both species, accounts for more than 86% of the artisanal fishery landing in biomass. We investigated the effects of small scale fishing over ten years (2004-2013) with generalized additive model fitting techniques using landings vs. fishing effort per gear and type of fishing gears in the Northern and southern parts of Senegal. The study revealed that these effects are more pronounced in the Northern area for S. aurita while they are more significant in the Southern area for S. maderensis. The purse seine, i.e the main Senegalese fishing gear targeting Sardinella, provides the most significant effects on S. aurita landings in both areas, while for S. maderensis, the most significant effects are shared between two fishing gears: purse seine in the Northern area and encircling gill nets in the Southern area. Spatio-temporal patterns of the effects of small scale fishing are described and the relative importance of fishing effort and fishing gear on both species at seasonal and inter-annual scales are discussed

The contribution of small scale fishing constraints on Sardinella landings in Senegalese waters [résumé]

ICAWA : International Conference AWA, Dakar, SEN, 13-/12/2016 - 15/12/2016Over the last decades, small pelagic fisheries have shown an increasing development in Senegal, especially those targeting Sardinella aurita and S. maderensis. Their landing and fishing effort quickly increase for both species, from less than 100,000 tons with 35,035 trips in the early 80's to a peak of over 400,000 tons with 86,427 trips in 2008. The Senegalese small scale pelagic fisheries, targeting both species, accounts for more than 86% of the artisanal fishery landing in biomass. We investigated the effects of small scale fishing over ten years (2004-2013) with generalized additive model fitting techniques using landings vs. fishing effort per gear and type of fishing gears in the Northern and southern parts of Senegal. The study revealed that these effects are more pronounced in the Northern area for S. aurita while they are more significant in the Southern area for S. maderensis. The purse seine, i.e the main Senegalese fishing gear targeting Sardinella, provides the most significant effects on S. aurita landings in both areas, while for S. maderensis, the most significant effects are shared between two fishing gears: purse seine in the Northern area and encircling gill nets in the Southern area. Spatio-temporal patterns of the effects of small scale fishing are described and the relative importance of fishing effort and fishing gear on both species at seasonal and inter-annual scales are discussed

Spatial management of Indian Ocean tropical tuna fisheries: potential and perspectives

Effective use of spatial management in the pelagic realm presents special challenges due to high fish and fisher mobility, limited knowledge and significant governance challenges. The tropical Indian Ocean provides an ideal case study for testing our ability to apply existing data sources to assessing impacts of spatial management on tuna fisheries because of several recent controversial spatial closures. We review the scientific underpinnings of pelagic MPA effects, spatio-temporal patterns of Indian Ocean tuna catch, by catch and fish movements, and the consequences of these for the efficacy of spatial management for Indian Ocean tropical tuna fisheries. The tropical Indian Ocean is characterized by strong environmental fluctuations, regular seasonal variability in catch, large observed tuna displacement distances, relatively uniform catch-per-unit-effort and bycatch rates over space, and high fisher mobility, all of which suggest significant variability and movement in tropical tuna fisheries that are simply not well adapted to static spatial closures. One possible exception to this overall conclusion would be a large time/area closure east of Somalia. If closed for a significant fraction of the year it could reduce purse-seine bycatch and juvenile tuna catch. Dynamic closures following fish migratory patterns are possible, but more focused information on fish movements will be needed for effective implementation. Fortunately, several recent improvements in conventional fishery management and reporting will likely enhance our ability to evaluate spatial and non-spatial management options in the near future, particularly as pertaining to bycatch species

The contribution of small scale fishing constraints on Sardinella landings in Senegalese waters [résumé]

ICAWA : International Conference AWA, Dakar, SEN, 13-/12/2016 - 15/12/2016Over the last decades, small pelagic fisheries have shown an increasing development in Senegal, especially those targeting Sardinella aurita and S. maderensis. Their landing and fishing effort quickly increase for both species, from less than 100,000 tons with 35,035 trips in the early 80's to a peak of over 400,000 tons with 86,427 trips in 2008. The Senegalese small scale pelagic fisheries, targeting both species, accounts for more than 86% of the artisanal fishery landing in biomass. We investigated the effects of small scale fishing over ten years (2004-2013) with generalized additive model fitting techniques using landings vs. fishing effort per gear and type of fishing gears in the Northern and southern parts of Senegal. The study revealed that these effects are more pronounced in the Northern area for S. aurita while they are more significant in the Southern area for S. maderensis. The purse seine, i.e the main Senegalese fishing gear targeting Sardinella, provides the most significant effects on S. aurita landings in both areas, while for S. maderensis, the most significant effects are shared between two fishing gears: purse seine in the Northern area and encircling gill nets in the Southern area. Spatio-temporal patterns of the effects of small scale fishing are described and the relative importance of fishing effort and fishing gear on both species at seasonal and inter-annual scales are discussed

Influence of climatic variables on Sardinella recruitment dynamique in Senegalese waters [résumé]

ICAWA : International Conference AWA, Dakar, SEN, 13-/12/2016 - 15/12/2016Several authors, with estimated abundance index, attempted to study the dynamic of Sardinella populations in relation with to their environment fluctuations in West African region. However, this relationship still poorly understood because of the complexity and difficulty to estimate this abundance index that depends on a variable difficult to identify, the fishing effort from artisanal fisheries. This study is a contribution to better understand the link between the variability of environmental conditions and the dynamic of Sardinella aurita and Sardinella maderensis in Senegalese waters using generalized additive model. Recruitment data of these two species estimated from the virtual population analysis model, sea surface temperature, coastal upwelling index, wind speed, surface chlorophyll concentration and north Atlantic oscillation index within 2004-2013 period were used. Our results showed that recruitment of these two small pelagic species are closely linked to changes in the climatic variables tested. However, variables playing the most critical roles differ from one species to another. For the S. aurita, the index of coastal upwelling is the most important factor, while for S. maderensis is the SST which plays the leading role. This study also reveals the existence of temperature, intensity of upwelling, wind speed, concentration of chlorophyll-a and north Atlantic oscillation index thresholds above or below which Sardinella recruitment success is low