Portuguese West Coast Research Articles

Struggling with fish age, a comparison of otolith preparation techniques to unravel age and growth of boarfish, Capros aper (Linnaeus, 1758)

Fish age and growth data are crucial for understanding vital species’ traits and their populations. Boarfish is a pelagic species widely distributed in the Northeast Atlantic that is one of the most discarded non-commercial species on the Portuguese coast. Due to its potential valorisation as a new fishery in the Northeast Atlantic, boarfish has become object of interest in several published studies. However, since no age standard protocol has been implemented for boarfish, studies have used a variety of different otolith preparation techniques to estimate age, leading to contradicting and discrepant results. This research aims to consolidate biological insights into boarfish age and growth, lay the foundation for a standardized ageing protocol and serve as a benchmark study for the Portuguese west coast before commercial exploitation. Through the comparison of two otolith ageing methodologies, this study recommends using whole otoliths as the best method, revealing a maximum age of 15 years. The growth pattern estimated, indicated a biphasic growth pattern, with a faster initial growth rate that slows down at 2.4 years, the moment of change, when energy is allocated for sexual maturation. This finding was corroborated by a maturity ogive and analysis of fish size and otolith length relationship.

Transcriptome profiling of the posterior salivary glands of the cuttlefish Sepia officinalis from the Portuguese West coast

Cephalopods like octopuses and cuttlefishes are known to secrete a ‘toxic saliva’ to inject into their prey, especially crustaceans since the XIX century. However, only in the mid-XX century were the first coleoid-specific toxins successfully isolated. Motivated by the growing interest on the global ocean as an almost inexhaustible source of novel bioactive compounds, we used RNA-Seq – based transcriptomics and de novo assembly of transcriptomes to screen the posterior salivary glands of Sepia officinalis (the common cuttlefish) from the Portuguese West coast for toxins and other bioactive proteins and peptides. Supported by microanatomical analyses, the posterior salivary glands constitute indeed the ‘venom gland’ whereas the more elusive anterior salivary glands (embedded in the buccal mass) are responsible for the production of mucin-rich saliva that is effectively the vehicle that transports the toxins as the venom is injected into the prey. Indeed, the transcriptomic profiling suggests that the cuttlefish venom is complex mixture of bioactive proteins, among which neurotoxins are major players, together with enzymes whose function is to digest the extracellular matrix to facilitate diffusion of the toxins. Nonetheless, by comparing with previous RNA-Seq data obtained from S. officinalis collected from other biogeographical areas, it may be suggested that significant inter-populational variation in venom composition can occur, which may potentially increase the span of bioactives secreted by these animals. We isolated and validated the full coding sequences for three important toxins, a cysteine-rich venom protein (CRVP), a venom insulin (VIns) and a cephalotoxin (CTX). The toxins seem to be relatively conserved among coleoids but diverging from other venomous mollusks such as cone snails. Their properties as potent modulators of glucose (in the case of VIns) and as potential neurotoxins (like CRVP and CTX) can render them primer targets for drug development.

A Cost–Benefit Approach to Assess the Physical and Economic Feasibility of Sand Bypassing Systems

The artificial sand bypassing systems are coastal interventions designed to transfer sediments from areas of accretion to areas where erosion is observed. The goal of these systems is to reduce the littoral drift gradients where sediment transport is interrupted (vicinity of river mouths or port structures) and maintain a balanced sediment distribution along the shoreline. However, these systems present high initial investment costs as well as ongoing expenses for operation and maintenance. To assess the feasibility of sand bypassing systems in mitigating coastal erosion from a long-term perspective (decades), a comprehensive understanding of their performance is necessary, considering both physical and economic aspects. Thus, a cost–benefit assessment numerical tool, COAST, is applied to evaluate and discuss the effectiveness of bypassing systems during their life cycle. First, a comprehensive analysis is conducted for a generic study area, and then, the feasibility of the systems is discussed for two real study areas of the Portuguese West coast (Barra-Vagueira and Figueira da Foz-Leirosa). The generic results demonstrate as the importance of systems location or transposed flow volumes. On the other hand, the analysis of the two real case studies revealed that, under similar conditions, the results of the cost–benefit analysis can be contradictory. For the Barra-Vagueira stretch, the work indicates that the bypass system is not economically viable, whereas for Figueira da Foz-Leirosa, it is cost-effective. The study shows the importance of the site-specific conditions to evaluate the best option for a medium to long-term planned coast, highlighting the relevance of the proposed approach to assess the physical and economic feasibility of sand bypassing systems.

COAST4US: APPLICATION OF THE COAST TOOL TO THE PORTUGUESE WEST COASTLINE

Over the years, people have been settling in coastal areas, as they provide opportunities, both economically and in terms of well-being and leisure. However, the coastline is also exposed to serious problems of coastal erosion, particularly on urban fronts, increasing the consequences derived from adjacent phenomena such as overtopping and flooding. It is therefore essential to deepen the study of strategies for the prediction, prevention and mitigation of this phenomenon. In this sense, COAST (Coast Optimization Assessment Tool), a tool for integrated cost-benefit analysis of coastal interventions to mitigate erosion problems, was developed. The COAST4US project - Application of the COAST tool to the Portuguese coast - aims to contribute to the feasibility of applying this tool in real situations, contributing to an efficient mitigation of coastal erosion, and providing decision makers with more and better information. The project proposes to apply COAST to three stretches of coastline at high risk of coastal erosion on the Portuguese west coast: Aveiro, Figueira da Foz, and Costa de Caparica. The project is divided in several tasks, including scenario modeling, cost prediction and benefit assessment, being this work focused on benefit assessment by estimating the value of each beach, and analyzing the effectiveness of three nourishment scenarios.

Comparing microplastics ingested by the bogue Boops boops (Teleostei: Sparidae) to those available in its feeding areas: A case study on the Portuguese west coast

Understanding the exposure of wild marine fish to microplastics (MPs) has been frequently assessed through the quantification and characterization of MPs found in stomachal contents. However, whether such particles mirror the MPs available in the environment or suggest a selectivity ability in the species, it has been scarcely analyzed. Here, in addition to investigating temporal patterns in the abundance and diversity of MPs ingested by Boops boops (Linnaeus, 1758) caught in coastal waters between Setúbal and Sesimbra (Portugal), we also aimed at comparing them with the patterns of MPs occurring locally, namely where the bogue feeds: at both surface water and seabed sediments. A total of 200 fish, 50 per month, were supplied at the local fish first sale concurrently with the water and sediments sampling (from October 2018 to January 2019). Fibers accounted for 93% of all MPs ingested and were also the main type of MPs extracted from sediments. Both food intake (inferred by fish gastrointestinal tract) and abundance of MPs per fish (1.80 ± 1.26; mean ± SD, n = 102) significantly decreased during the 4 month-period analyzed. Such decreasing tendency is potentially related to this species reproduction season. Despite the distinct fluctuations observed in the abundance of MPs found in both feeding areas of the bogue, it was possible to detect similarities between fish and sediments regarding the predominance of fibers, namely those belonging to the smaller size class. Yet, the prevailing colors differed, suggesting a selection capability of the bogue. Further studies taking place in spring/summer months (out of the reproduction season) are thus needed to clarify how MPs ingestion will vary in this species and consequently interfere with its ability to mirror the MP pollution patterns in this coastal region.

A Cost–Benefit Approach to Discuss Artificial Nourishments to Mitigate Coastal Erosion

Worldwide, artificial nourishments are being considered as one of the main coastal erosion mitigation measures. However, this solution is not permanent, since the natural removal of sediments that occurs after the sand deposition leads to the need of re-nourishment projects; thus, its performance and longevity dependent on several design parameters (placement site and extension alongshore, frequency, and volume, etc.) In this work, a methodological approach for cost–benefit assessment is applied to analyze the performance of artificial nourishments from a physical and economical point of view, by analyzing the effectiveness of different scenarios. The study was developed considering two study areas: a hypothetical situation (generic study area) and a real coastal stretch (Barra-Vagueira, located in the Portuguese west coast). The findings show the complexity in defining the best nourishment option, being dependent on the wave climate, site specific conditions, and main goal of the intervention. The proposed cost–benefit approach allows one to obtain and compare the physical and economic performance of artificial nourishments to mitigate coastal erosion, aiding the decision-making processes related to coastal planning and management.

Distribution patterns of microplastics in subtidal sediments from the Sado river estuary and the Arrábida marine park, Portugal

Understanding local accumulation patterns of microplastics in subtidal sediments is crucial to assess how available such particles are for ingestion by benthic feeders and to identify the potential pollution sources in the region upon which is urgent to act. The coastal urban centers of Setúbal and Sesimbra (Portugal) and the multiple activities taking place at the contiguous Sado estuary and in the sheltered waters of Professor Luiz Saldanha Marine Park make this a relevant case study about MPs pollution in the seabed. Here, a short-term investigation assessed the spatiotemporal distribution, abundance, and composition of MPs on the nearshore seabed. Sediment samples were monthly collected from summer 2018 to winter 2019, in six stations. Despite the differences observed in rainfall between campaigns, no distinct patterns were detected in the accumulation of MPs throughout the sampled months. Yet, strong variations occurred among stations. The abundance of MPs in the Sado estuary (1042.8 ± 430.8 items kg−1) was higher in comparison to all the stations located along the marine park (52.9 ± 31.9 items kg−1). Fragments comprised 70% of particles found in estuarine sediments, while fibers were the predominant type in marine sediments. The majority of MPs collected in the estuary shared the same size class as the best represented grain size fraction: 0.250–0.500 mm. On average, the ratio between the abundance of MPs and the abundance of meiofauna organisms was higher in the estuary, suggesting more encounter rates, by both meiofauna and their predators, with MPs. The distribution of MPs throughout the study area was moderately correlated with sediment sorting and organic matter content. Also, the distinct mineralogical content of each station indicates a reduced sediment transit between stations and consequently a weak exportation of MPs from the estuary. The majority of the polymers identified by Fourier Transform Infrared Spectroscopy was denser than seawater. Polyethylene terephthalate represented 41% of the items analyzed and was mostly assigned to fibers and fiber bundles. Unveiling the distribution patterns of MPs along this segment of the Portuguese west coast enabled to identify a high-risk area where the implementation of preventive measures is urgent.

Retrieval of nearshore bathymetry from Sentinel-1 SAR data in high energetic wave coasts: The Portuguese case study

The ability to derive bathymetry using remote sensing techniques enables rapid and cost-efficient mapping of large coastal areas. This contribution focuses on the application of both fast Fourier transform (FFT) and wavelet spectral analysis to obtain satellite-derived bathymetry maps of the nearshore, from freely available and easily accessible Sentinel-1 synthetic aperture radar (SAR) data with 10 m pixel resolution. For this purpose, an extension of 220 km of the Portuguese west coast is analyzed using six satellite images obtained during the years 2018, 2019 and 2020. This extension allows to assess the applicability to coastal sectors with distinct geomorphological constraints. The peak wave periods corresponding to the acquisition of these images approximately range between 11 and 16 s. The spectral analysis is carried to estimate the water depths in near-shore water regions from the observed wavelength patterns. This signature of the sea surface, reflected in the variations of the wavelengths, is captured by the satellite images, making it possible to infer the underlying bathymetry. The bathymetric estimates obtained from both methodologies are compared with data extracted from the Coastal Nautical Charts provided by the Portuguese Hydrographic Institute. Wavelet image processing methodology shows very positive results, particularly extending the depth inversion limits of the FFT methodology, allowing to obtain bathymetric data for the entire shoaling zone where the wavelength patterns are visible. The achieved results also highlight that both FFT and wavelet methodologies are dependent from the seabed slope. For gentle slopes, the inferred depths from 2018 SAR images lead to relative errors between 2.5 and 20% when compared with the observed isobaths (10, 20 and 30 m). For steeper slopes, the errors are generally greater than 20% and increase with depth. The capabilities of the wavelet methodology to map shallow marine environments for high energetic coasts seems promising, regarding research purposes and management interventions.

Modeling Dynamic Processes of Mondego Estuary and Óbidos Lagoon Using Delft3D

Estuarine systems currently face increasing pressure due to population growth, rapid economic development, and the effect of climate change, which threatens the deterioration of their water quality. This study uses an open-source model of high transferability (Delft3D), to investigate the physics and water quality dynamics, spatial variability, and interrelation of two estuarine systems of the Portuguese west coast: Mondego Estuary and Óbidos Lagoon. In this context, the Delft3D was successfully implemented and validated for both systems through model-observation comparisons and further explored using realistically forced and process-oriented experiments. Model results show (1) high accuracy to predict the local hydrodynamics and fair accuracy to predict the transport and water quality of both systems; (2) the importance of the local geomorphology and estuary dimensions in the tidal propagation and asymmetry; (3) Mondego Estuary (except for the south arm) has a higher water volume exchange with the adjacent ocean when compared to Óbidos Lagoon, resulting from the highest fluvial discharge that contributes to a better water renewal; (4) the dissolved oxygen (DO) varies with water temperature and salinity differently for both systems. On the one hand, for Mondego Estuary during winter the DO levels mainly fluctuate with salinity. On the other hand, for Óbidos Lagoon, DO distribution is determined by both water temperature and salinity. During summer, the high residence time and water temperature limit the DO levels in both systems. The high transferability and superior stability of Delft3D make this model a foundation for realistic simulation and research of distinct estuarine systems, giving support to their maintenance and restoration.

Modeling Wave Overtopping on a Seawall with XBeach, IH2VOF, and Mase Formulas

The advances in computational fluid dynamics have made numerical modeling a reliable complementary tool to the traditional physical modeling in the study of the wave overtopping phenomenon. This paper addresses overtopping on a seawall by combining the numerical models XBeach (non-hydrostatic and Surfbeat modes) and IH2VOF, and the Mase formulas. This work is structured in two phases: (i) phase I assesses the performance of numerical models and formulas in modeling wave run-up and overtopping on a seawall for a solid profile bottom and representative hydro-morphologic conditions of a study site in the Portuguese west coast; (ii) phase II investigates the effect of the profile bottom variation in the overtopping phenomenon for extreme maritime storm field conditions of the study site, considering a solid bottom and a varying sandy bottom. The results indicate that XBeach underestimates the wave energy, and the frequency and intensity of the overtopping occurrences predicted by IH2VOF; the numerical models’ run-up and overtopping discharge predictions are overestimated by the Mase formulas, in simplified and in storm field conditions; and the variation of the bottom morphology throughout the storm event greatly influences the XBeach predictions, while the Mase results are mostly influenced by the bottom roughness.

Estimation of the nearshore bathymetry from high temporal resolution Sentinel-1A C-band SAR data - A case study

The study of the changes in swell properties in the nearshore domain due to interaction with the sea-bottom to infer the bathymetry has deserved some attention in the last few years. Satellite Remote Sensing images, in particular Synthetic Aperture Radar (SAR), have been used to produce a directional wave spectrum by Fast Fourier Transform (FFT), from which the wavelength and wave direction of the ocean surface waves can be retrieved. These wave properties can be directly used in the linear dispersion relation to estimate the water depth.The present work takes advantages from the very short revisit times of the Sentinel-1A with C-band (5.405 GHz) SAR images with 10 m of spatial resolution to study the repeatability of this methodology for deriving the nearshore sea-bottom morphology, using a case study in the Aveiro region, located in the Portuguese West Coast. This site is exposed to high energetic wave climate of the North Atlantic Ocean. Overall, a set of four images were selected for the analysis.The robustness of the FFT methodology to calculate the wavelength and wave direction from SAR images was analysed through calculating their standard deviations. The errors of estimating the local bathymetry from these quantities was accessed which allowed to quantify the water depth limits of application of this methodology.The set of images was used to establish a bathymetric estimation that merges the derived bathymetry of each image. The computed bathymetry was quantitatively compared with the measurements made in 2013 and available at RAIA Observatory. The relative error of the water depth ranges between 6% and 10%, but increases for the higher depths and depends on the accuracy of the computed wavelength at deep-waters. The merged derived bathymetry also provides a better approximation for the measured bathymetry than those derived from the individual images.

Razorbill Alca torda mortality in the Portuguese west coast

This study presents data on mortality events of the species Alca torda in the central region of Portugal and data was also used to improve reporting of species biometrics in wintering grounds. A total of 646 razorbills were collected between Aveiro and Praia de Santa Rita (central coast of Portugal) from January to April of 2012, 2013, 2014 and 2016. This species is listed as Near Threatened and population estimates are declining. The present study revealed an important bycatch-based mortality of razorbills in good body condition and evidence indicating entanglement in fishnets and drowning as the birds’ main cause of death. This study also revealed a significant increase over the years in wing length of sub-adults in their wintering range. Further long-term studies are necessary to verify the significance at population levels of the high bycatch mortality in this area (mainly due to IUU fisheries) and of the possible wing length increase of migratory razorbill sub-adults.

Characterization of Maritime Storms and Analysis of their Effect on the Beaches South of the Mondego River (Portugal)

Santos, M.I.; Oliveira, F.S.B.F., and Trigo-Teixeira, A., 2018. Characterization of Maritime Storms and Analysis of their Effect on the Beaches South of the Mondego River (Portugal). In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 266–270. Coconut Creek (Florida), ISSN 0749-0208.In the study of coastal processes and coastal dynamics, the analysis of the storms impact is one of the most discussed topics in terms of management and defense of the coastal sector. The Portuguese west coast is exposed to the energetic wave climate that characterizes the North Atlantic, thus requiring permanent care as regards the efficient coastline management and planning. Indeed, the risk associated with erosion and flooding of vulnerable areas is a constant concern, making it imperative to predict the impact of these events and the response of the beach-dune systems. This study focuses on maritime storms and on the morphological response of the beach to these short-term events. The two main objectives are to characterize the storms regime in the coastal stretch between the Mondego and the Lis rivers' inlets based on the wave time series (hindcast) from the period 1952–2010, and to evaluate the impact of the storms duration on erosive events, using a short-term morphodynamic numerical model, LITPROF. This model is used for the analysis of the effect of storms on the beach morphology and thus, for comparing the erosive effect of events with the same relative storm power and different duration. The statistical analysis of the wave climate time series showed a coastal storms regime with high inter-annual and intra-annual variability in number, duration and relative storm power of events, characterized by a strong seasonality, with an average duration and relative storm power of 3 days and 2654 m2.h, respectively. The most frequent events are simultaneously in the classes [1–2[ days and [800–1600[ m2.h (36% of occurrences). The numerical model, applied to several scenarios, predicted the dominance of the duration factor for storms with similar relative storm power, leading to the conclusion that longer duration storms always generate larger erosive effects (and higher transport rates) in the cross-shore profile, when compared with storms of shorter duration.

Variability of wave parameters and Hmax/Hs relationship under storm conditions offshore the Portuguese continental coast

The relevance of long-term wave storm characterization based on in-situ measurements extends from marine ecosystems management to the design of ocean engineering structures. We analyze wave storms recorded over almost three decades (1988–2015) in three points offshore the Portuguese continental coast located between 83 and 97 m water depth. We provide Probability Distribution Functions for mean wave direction (θm), directional wave spreading (σθ), significant wave height (Hs), maximum wave height (Hmax), mean wave period (Tz) and, Hmax/Hs relationship based on four storm datasets. In the highly energetic Portuguese west coast (Leixões and Sines), Hmax and Hmax/Hs ranged between 5.5 and 17.3 m and 1.16 to 2.47, respectively. We conclude that a GEV distribution can represent Hmax and Hmax/Hs variability at the three analyzed locations. Despite the differences in the dataset lengths and the differences in the range and variability of θm, σθ, Tz, Hs, and Hmax, we found that the range and variability of Hmax/Hs are very similar for the four storm datasets. For the analyzed period, σθ ranged between 8 and 52° and 10 to 59° in the west and south coast (Faro Atlantic and Faro Levante storms), respectively, and its variability can be described by a log-logistic distribution.

Asexual brooding in the sea-anemone Actinia schmidti: is temperature a key factor?

Event Abstract Back to Event Asexual brooding in the sea-anemone Actinia schmidti: is temperature a key factor? Eliana A. Sales1*, Luís F. Afonso1 and Ana M. Pereira1, 2 1 Instituto Universitário de Ciências Psicológicas, Sociais e da Vida, Portugal 2 Centro de Ciências do Mar e do Ambiente (MARE), Portugal Although the majority of sea anemone species exhibit variations of sexual and asexual reproduction, there is a lack of data concerning the use of these different forms of reproduction in natural conditions. Actinia schmidti Monteiro, Thorpe and Solé-Cava, 1997 is distributed in the Northeastern Atlantic from the Bay of Biscay to Morocco and in the Mediterranean coastline. In its original description, this species is considered to reproduce sexually and not to perform brooding within the gastrovascular cavity, but recent works contradict this statement. In the present study, the seasonality of brooding in A. schmidti on the Portuguese west coast was investigated Throught the course of a year. Active peaks of viviparous reproduction were recorded during the summer months and decreased in the remaining seasons, suggesting that temperature plays a major role. In order to clarify the effect of temperature in brooding, an experimental study was performed in artificially controlled conditions. Twenty-one individuals were half-sectioned and left to heal. Each of the clones produced was kept during two months in different tanks, at distinct water temperatures. At higher temperatures, the number of adults inclubating polyps and the total number of brooded polyps were higher, altough these differences were not significant. However, these results can be influenced by a low sample size and or low temperature amplitude in the experimental conditions. Keywords: asexual reproduction, Cnidaria, Anemone, brooding, high temperature, Portugal Conference: IMMR'18 | International Meeting on Marine Research 2018, Peniche, Portugal, 5 Jul - 6 Jul, 2018. Presentation Type: Poster Presentation Topic: Biodiversity, Conservation and Coastal Management Citation: Sales EA, Afonso LF and Pereira AM (2019). Asexual brooding in the sea-anemone Actinia schmidti: is temperature a key factor?. Front. Mar. Sci. Conference Abstract: IMMR'18 | International Meeting on Marine Research 2018. doi: 10.3389/conf.FMARS.2018.06.00058 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 03 Apr 2018; Published Online: 07 Jan 2019. * Correspondence: Ms. Eliana A Sales, Instituto Universitário de Ciências Psicológicas, Sociais e da Vida, Lisbon, Portugal, eliana.s.sales@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Eliana A Sales Luís F Afonso Ana M Pereira Google Eliana A Sales Luís F Afonso Ana M Pereira Google Scholar Eliana A Sales Luís F Afonso Ana M Pereira PubMed Eliana A Sales Luís F Afonso Ana M Pereira Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Portuguese West Coast tourism resorts: an unfinished landscape of territorial liabilities

ABSTRACTThe research focuses on Portuguese West Coast tourism resorts and addresses the problem of unfinished estates as territorial liabilities left by the Global Financial Crisis on residential tourism and tourism-driven urbanization. After a significant expansion during the golden age, resorts have suffered drastic consequences under the crisis, financial imbalance and stagnation of the real estate market. This situation brings additional problems to land management and adequate responses have not been provided yet. Focusing on the municipality of Óbidos, this paper aims to describe the territorial changes induced by the development of resorts, criss-crossing a morphological analysis with the understanding of the context of the Global Financial Crisis and the assessment of the regulatory framework.

Unravelling region-specific environmental drivers of phytoplankton across a complex marine domain (off SW Iberia)

Phytoplankton, the dominant marine primary producers, are considered to be highly sensitive indicators of ecosystem condition and change. The southwest area off the Iberian Peninsula (SWIP, NE Atlantic) is located in a biogeographical transition zone between temperate and subtropical waters, and classified as being very vulnerable to climate change. SWIP includes a variety of oceanic and coastal domains, under the influence of topographic irregularities, coastal upwelling and continental freshwater outflows, that collectively challenge the understanding of phytoplankton dynamics and controls. This study aimed to evaluate patterns in seasonal and interannual variability in phytoplankton and underlying environmental determinants within specific regions of SWIP, during a 15-year period (1997–2012), and to assess whether climate variability affects the regions in different ways. Empirical Orthogonal Function (EOF) analysis of satellite-retrieved sea surface chlorophyll-a concentration (Chl-a), acquired from the Ocean Colour Climate Change Initiative (OC-CCI), 4-km, 16-day resolution, was used to regionalize the study area. Region-specific Chl-a variability patterns and their linkages with environmental determinants were explored using Generalized Additive Mixed Models (GAMM). A set of local physical-chemical variables, derived from satellite and model data, and large-scale climate indices, were used as environmental variables. EOF analysis of Chl-a variability over the heterogeneous SWIP area identified nine coherent regions, with distinctive variability patterns (4 coastals, 2 slopes and 3 open-ocean regions). Region-specific GAMM models explained between 32% and 82% of Chl-a variance, with higher explanatory power (>61%) for open ocean regions and coastal regions under increased riverine influence. Chl-a model predictors, as well as their effects, varied markedly among SWIP regions. However, climate-sensitive local environmental variables (sea surface temperature – SST and photosynthetically available radiation) emerged as the most influential general predictors overall, and large-scale climate indices showed significant but minor effects. Over oceanic SWIP regions, Chl-a (0.08–1.50μgL−1) showed a uni-modal annual cycle, with increases during the mixed-layer deepening and late-winter maxima, reflecting seasonal changes in SST and ocean stratification, and probably related to increased nutrient availability and/or decreased mortality. Over coastal regions south of 37°N, Chl-a (0.23–10μgL−1) also benefited from riverine discharges, mostly during winter, and upwelling induced by zonal westerly winds, stronger during summer. Over the Portuguese west coast region, Chl-a (0.26–2.20μgL−1) showed a uni-modal annual cycle, with summer maxima, associated with the stimulatory effects of meridional northerly winds and coastal upwelling that partially extended into slope waters. Chl-a interannual variability showed zonal differences within SWIP, with significant interannual patterns only for regions south of 37°N. Nonetheless, contrasting trends were detected in coastal (decline) and oceanic (increase) regions, possibly a consequence of between-region differences in the relative roles of nutrient and light limitation, corresponding to significant interannual increases in wind speed and mixed layer depth. Our study used a biologically-relevant objective regionalization of a heterogeneous area, to elucidate phytoplankton dynamics and controls. The region-specific associations observed between phytoplankton and multiple climate-sensitive environmental drivers over the SWIP area reinforce the role of phytoplankton as a strategic element for evaluating ecosystem responses to climate variability and change.

Performance of a Fuzzy ARTMAP Artificial Neural Network in Characterizing the Wave Regime at the Port of Sines (Portugal)

ABSTRACT Santos, F.L.; Reis, M.T.; Fortes, C.J.E.M.; Lotufo, A.D.; Neves, D.R.C.B.; Poseiro, P., and Maciel, G.F., 2016. Performance of a fuzzy ARTMAP artificial neural network in characterizing the wave regime at the Port of Sines (Portugal). Techniques based on artificial neural networks (ANNs) have been increasingly applied to predict emergency situations, such as extreme wave conditions, wave overtopping or flooding, and damage to maritime structures, in coastal and port areas. In this work, a fuzzy adaptive resonance theory with mapping (FAM) ANN was trained to predict the wave regime both inside and at the entrance to the Port of Sines, one of the major trade and economic gateways of the Iberian Peninsula, located on the Portuguese west coast. In situ measurements using pressure sensors, wave buoy data, and results from two numerical wave propagation models—simulating waves nearshore (SWAN) and diffraction refraction elliptic approximation mild slope (DREAMS)—were used to train and validate the ANN....

Wandering mussels: using natural tags to identify connectivity patterns among Marine Protected Areas

Knowledge of connectivity pathways in the marine environment is crucial for understanding the spatial structure of populations and for developing appropriate monitoring and management strategies. Here, we used the mussel Mytilus galloprovincialis as a model species to investigate connectivity patterns within the Berlengas and Arrabida Marine Protected Areas (MPAs) along the central Portuguese west coast. We generated an atlas of location-specific environmental markers based on the microchemistry of bivalve larval shells (using laser ablation inductively coupled plasma mass spectrometry). This atlas was then employed to trace the natal origins of newly settled mussels and generate connectivity matrices among populations. Our results reflected 3 distinctive chemical signatures in larval shells, corresponding to 3 regions: Estremadura, Cascais and Arrabida. Linear discriminant analyses allowed for a high reclassification success (average of 79.5% of jackknifed cross-validated cases correctly assigned) based on 8 of the 16 trace elements analyzed (B, P, Co, Cu, Zn, Ce, Pb and U). The population connectivity matrix identified different dispersal pathways for mussel larvae, in particular a predominantly northward dispersion pattern in July 2013. This pattern was consistent with simultaneous environmental physical data, which confirmed an extended period of wind reversal and upwelling relaxation. The Arrabida MPA was an important source population for the other 2 regions and showed high rates of self-recruitment but limited connectivity to the Berlengas MPA. These direct measures of demographic connectivity can be a powerful tool to inform policymakers on the conservation and management of ecologically coherent networks of protected areas in coastal marine ecosystems.

Early life history of larvae and early juvenile Atlantic horse mackerel Trachurus trachurus off the Portuguese west coast

Early life history traits (ELHTs) are key to understand recruitment patterns in marine animals. However, for reef fishes, studies on ELHTs are mainly focused on tropical systems and little is known for temperate reefs. In this study we used SMURFs (Standard Monitoring Units for the Recruitment of Reef Fishes) to collect fish in a temperate rocky reef system (Arrábida Marine Park, Portugal) on a weekly basis for three months during the recruitment period. Six sub-surface SMURFs sampled 2490 Atlantic horse mackerel (Trachurus trachurus) postlarvae and juveniles. Sagittal and lapilli otoliths were extracted from a subsample of 296 fish and ELHTs, such as size and age at settlement, growth rate and age at first secondary growth formation were examined. Additionally, we tested three growth curves and selected the best suited to back-calculate the hatching pattern based on the lengths of all sampled fish. Standard length ranged from 6.13mm to 48.56mm and subsampled fish were aged between 19days to 44 days. Age and size at settlement were estimated between 19days and 36days for individuals of 6.13mm and 24.95mm, respectively. Otolith shape changed clearly with increasing age and, on average, secondary growth started to form on day 33 (±3 days). Age/length relationship was well described by a Gompertz growth model which was used to back-calculate hatching dates. Four distinct hatching cohorts were identified with fish of the earliest cohort showing a faster body and otolith growth. This study indicates that the nearshore environment might have an important role in the early growth, development and hence recruitment of Atlantic horse mackerel. Information on the early life history of Atlantic horse mackerel is key to understand recruitment processes for this economically and biologically important species.