Francesc Sardà

Institut Marqués, Spain, Barcelona, Barcino, Catalonia, Spain

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Publications (133)158.96 Total impact

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    ABSTRACT: Patterns of how the Norway lobster (Nephrops norvegicus L.) emerges from its burrow in relation to sea currents at different times of the day–night cycles is currently unknown. The degree of influence of these variables when simulated in controlled laboratory conditions entails great technical and technological difficulties. This paper presents the development of an integrated control system that manages a set of aquariums generating water currents and patterns of light. The solution proposed combines the use of commercial equipment and a custom electronic design in order to achieve the required specifications with cost-minimization. The control system has circulation pumps and visible and infrared LED lighting to recreate different currents and light conditions. Preliminary results show the control system works properly and all components responded as expected during the experiments.
    No preview · Article · Jun 2015 · Measurement
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    ABSTRACT: Discards are the portion of animal and plant material in the catch that is dumped back at sea. The Common Fisheries Policy plan proposed by the European Commission for 2014-2020 presents a controversial goal: to enforce the landing of fishing discards as a measure to encourage their reduction. This historical and political decision will shape the future of the fishing exploitation in European Seas. Discards generated by European fleets are not negligible, and its reduction is an ecological, socioeconomical and moral imperative. However, it must be achieved through the reduction in discards at source and the promotion of selective and non-destructive gears. We argue it is doubtful that this discard ban will result in an effective reduction of discards. The proposed measure may, in fact, negatively affect ecosystems at all levels of biological hierarchy by disregarding the Ecosystem-Based Approach to Fisheries and the Precautionary Principle. It could negatively impact several species by increasing fishing mortality, also commercial species if discards are not accounted in the total allowable catch. Communities preying on discards will likely be affected. The role discards currently play in the energy turnover of current ecosystems will be modified and should be fully evaluated. The landing of discards will likely generate new markets of fishmeal due to the growing demands for marine living resources. The ban will require substantial public investment to deal with technical problems on board and to control and enforce. Therefore, this measure should be only implemented after rigorous scientific and technical studies have been developed.
    Full-text · Article · Mar 2015
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    ABSTRACT: The Norway lobster, Nephrops norvegicus, can be captured by haul nets only during the emergence from its burrow. In the last few decades, an extensive field research revealed distinct diel (24-h–based) catchability patterns at different depths. Laboratory experiments suggested that burrow emergence (used as a proxy of catchability) is endogenously controlled via a circadian system. Results were usually presented in terms of mean effects without a quantification of inter-individual variability and arrhythmia. Here, we studied the burrow emergence of 52 adult Nephrops by an infrared actograph endowed with an artificial burrow. Animals were exposed to 12-12 h light-darkness cycle, simulating photic condition of the lower shelf. Forty-five animals showed rhythmic emergence (87%), while seven were arrhythmic (13%). Rhythmic animals were clustered according to their timing of emergence: 54% at dusk and 4% at dawn. Moreover, other animals showed fully diurnal or nocturnal emergence (10% and 19%, respectively). The comparison of our results with those derived from temporally scheduled trawling indicates that bimodal catch patterns observed in shelf populations are poorly observed during individual experiments in the laboratory, where the same light conditions are simulated. Nephrops burrow emergence seems to be the result of a mixed endogenous-exogenous control, while arrhythmia could also be present in the wild.
    No preview · Article · Nov 2014 · Scientia Marina
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    ABSTRACT: The field measurements of swimming activity rhythms of fishes are scant for the difficulty of counting individuals at a high frequency over a large period of time. Cabled observatory video monitoring allows such a sampling at a high frequency. Unfortunately, automated animal visual counting is still a major bottleneck. We developed a new automated video-imaging protocol for the 24-h continuous counting of fishes in calorimetrically calibrated time-lapse photographic outputs, taken by a shallow water (20 m depth) cabled video-platform, the OBSEA. All the images were acquired within a standardized Region Of Interest, represented by a 2 x 2 m methacrylate panel, endowed with a 9-colour calibration chart, and calibrated using the recently implemented “3D Thin-Plate Spline” warping approach.
    Full-text · Dataset · Oct 2014
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    Giulia Gorelli · Joan B Company · Francesc Sardà
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    ABSTRACT: The red shrimp is the most important demersal resource in the Northwest Mediterranean. In Northeast Spain it is fished by bottom trawling and constitutes a great part of the economical incomes for the local fishermen associations. In Palamós, the most important harbor for this fishery in the area, a management plan regulating this fishery has been established in May 2013, aiming to reduce fishing effort and protect juveniles. In this work we investigate whether the management strategy adopted in Palamós is appropriate and how that could be improved according to the stock status and fishery characteristics. For this purpose we analyze the trends of several historical series of data including fishing effort, landings, CPUEs and size frequencies in the captures. We found that fishing effort directed to this species has increased massively starting form the second half of the last century, accompanied by a marked decline in CPUEs. Overfishing of the stock was highlighted since 1984. Given the results obtained in this work, we consider the management strategy established in Palamós appropriate to achieve the aim of sustainability of the red shrimp fishery.
    Full-text · Article · Apr 2014
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    Full-text · Conference Paper · Mar 2014
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    ABSTRACT: The deep-sea red shrimp Aristeus antennatus is the most valuable demersal resource exploited by the trawling fleets of Catalonia (NE Spain). In this area, the abundance of this species displays important seasonal fluctuations, forming dense aggregations at different depths in different times of the year. The fishing fleet is known to target such aggregations. In this context, detailed knowledge of spatial and temporal distribution of the fishing effort and size-class of catches is crucial, if we are to establish an ad hoc management strategy involving specific actions on a seasonal or spatial basis, such as temporary and spatial fishing closures. For this study we obtained from the Spanish Ministry of Agriculture, Livestock and Fishery the VMS (Vessels Monitoring System) data relative to the trawling fleets of Catalonia from 2005 to the actuality. For two of the main ports in the area, Blanes and Palamós, we also disposed of data on daily landings per vessel per each commercial size of the resource (four for Palamós and two for Blanes), supplied by the local fishermen associations. By merging the two datasets, we were finally able to draw maps showing spatial distribution of fishing effort, catches and CPUEs at different times of the year, considering size classes altogether or separately. The results obtained so far show that fishing effort concentrates on the heads of the submarine canyons. These areas host a consistent aggregation of juveniles of red shrimp typically in winter, when they are recruiting to the fishing area from deeper waters.
    Full-text · Conference Paper · Mar 2014
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    ABSTRACT: The distribution, type and quantity of marine litter accumulated on the bathyal and abyssal Mediterranean seafloor has been studied in the framework of the Spanish national projects PROMETEO and DOS MARES and the ESF-EuroDEEP project BIOFUN. Litter was collected with an otter trawl and Agassiz trawl while sampling for megafauna on the Blanes canyon and adjacent slope (Catalan margin, north-western Mediterranean) between 900 and 2700. m depth, and on the western, central and eastern Mediterranean basins at 1200, 2000 and 3000. m depth. All litter was sorted into 8 categories (hard plastic, soft plastic, glass, metal, clinker, fabric, longlines and fishing nets) and weighed. The distribution of litter was analysed in relation to depth, geographic area and natural (bathymetry, currents and rivers) and anthropogenic (population density and shipping routes) processes. The most abundant litter types were plastic, glass, metal and clinker. Lost or discarded fishing gear was also commonly found. On the Catalan margin, although the data indicated an accumulation of litter with increasing depth, mean weight was not significantly different between depths or between the open slope and the canyon. We propose that litter accumulated in the canyon, with high proportions of plastics, has predominantly a coastal origin, while litter collected on the open slope, dominated by heavy litter, is mostly ship-originated, especially at sites under major shipping routes. Along the trans-Mediterranean transect, although a higher amount of litter seemed to be found on the Western Mediterranean, differences of mean weight were not significant between the 3 geographic areas and the 3 depths. Here, the shallower sites, also closer to the coast, had a higher proportion of plastics than the deeper sites, which had a higher proportion of heavy litter and were often affected by shipping routes. The weight of litter was also compared to biomass of megafauna from the same samples. On the Blanes slope, the biomass of megafauna was significantly higher than the weight of litter between 900 and 2000. m depth and no significant differences were found at 2250 and 2700. m depth. Along the trans-Mediterranean transect, no significant differences were found between biomass and litter weight at all sites except in two sites: the Central Mediterranean at 1200. m depth, where biomass was higher than litter weight, and the Eastern Mediterranean at 1200. m depth, where litter weight was higher than biomass. The results are discussed in the framework of knowledge on marine litter accumulation, its potential impact on the habitat and fauna and the legislation addressing these issues.
    No preview · Article · Nov 2013 · Progress In Oceanography
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    ABSTRACT: Field measurements of the swimming activity rhythms of fishes are scant due to the difficulty of counting individuals at a high frequency over a long period of time. Cabled observatory video monitoring allows such a sampling at a high frequency over unlimited periods of time. Unfortunately, automation for the extraction of biological information (i.e., animals' visual counts per unit of time) is still a major bottleneck. In this study, we describe a new automated video-imaging protocol for the 24-h continuous counting of fishes in colorimetrically calibrated time-lapse photographic outputs, taken by a shallow water (20 m depth) cabled video-platform, the OBSEA. The spectral reflectance value for each patch was measured between 400 to 700 nm and then converted into standard RGB, used as a reference for all subsequent calibrations. All the images were acquired within a standardized Region Of Interest (ROI), represented by a 2 × 2 m methacrylate panel, endowed with a 9-colour calibration chart, and calibrated using the recently implemented "3D Thin-Plate Spline" warping approach in order to numerically define color by its coordinates in n-dimensional space. That operation was repeated on a subset of images, 500 images as a training set, manually selected since acquired under optimum visibility conditions. All images plus those for the training set were ordered together through Principal Component Analysis allowing the selection of 614 images (67.6%) out of 908 as a total corresponding to 18 days (at 30 min frequency). The Roberts operator (used in image processing and computer vision for edge detection) was used to highlights regions of high spatial colour gradient corresponding to fishes' bodies. Time series in manual and visual counts were compared together for efficiency evaluation. Periodogram and waveform analysis outputs provided very similar results, although quantified parameters in relation to the strength of respective rhythms were different. Results indicate that automation efficiency is limited by optimum visibility conditions. Data sets from manual counting present the larger day-night fluctuations in comparison to those derived from automation. This comparison indicates that the automation protocol subestimate fish numbers but it is anyway suitable for the study of community activity rhythms.
    Full-text · Article · Nov 2013 · Sensors
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    Giulia Gorelli · Francesc Sardà · Joan B. Company
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    ABSTRACT: The fishery of the red shrimp Aristeus antennatus is one of the main fisheries in the western Mediterranean. In this work we evaluated the status of the A. antennatus fishery in the Catalan region (NE Spain) in recent years, 2008-2010, and compared it with the last historical available data, 1984-1989. Fishing mortality and population biomass displayed high inter-annual variability. Population biomass values were higher for the recent period. Yield per recruit analysis showed a general overfishing pattern, for both periods. In general inter-annual variability of estimates suggested the existence of non-fishery effects affecting the population dynamics of this species in the area.
    Full-text · Conference Paper · Oct 2013
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    ABSTRACT: High frequency monitoring and the reducing of disturbance of sampling activities have a vital importance in the study of fish communities. The aim of this paper is to describe temporal patterns in habitat utilization by a coastal fish assemblage throughout the year 2012. A high frequency long term photo identification monitoring has been carried out with this objective. At about 63.000 individuals representing 28 species were identified, suggesting the occurrence of different day-night rhythms among them. Future comparisons with physical parameters will be developed to get a better understanding of their movement patterns.
    Full-text · Conference Paper · Oct 2013
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    ABSTRACT: The rhythmic behavior of marine species generates uncertainties in population and biodiversity assessments if the frequency of sampling is too low and irregular over time. Few attempts have been made to link community changes to the rhythmic behavior of individuals within populations. Cabled video observatories can be used to explore community changes over different temporal windows as a result of the activity rhythms of individuals within populations. In this study, we used, for the first time, a coastal cabled observatory (OBSEA) to video monitor activity rhythms of different fish species within an artificial reef area at a high frequency. During 1 mo, 30 min daily count patterns were continuously measured and compared with the corresponding solar irradiance. A significant (p < 0.05) day-night patterning was observed in the majority of recognized taxa by Chi-Square periodogram analysis. Three types of rhythms were identified in waveform plotting: (1) diurnal (Chromis chromis, Coris julis, Diplodus annularis, D. cervinus, D. sargus, D. vulgaris, Serranus cabrilla, Dentex dentex, Symphodus sp.); (2) nocturnal (Atherina sp. and Scorpaena sp.); and (3) crepuscular (Apogon imberbis, Oblada melanura, and Spicara maena). Diurnal species clustered around maximum averaged irradiance (computed from a cosinor analysis). The results were discussed evaluating whether visual count time series represent a reliable proxy for the swimming activity rhythms of individuals and whether the complex habitat use of coastal fishes would require the use of spatial networks of cameras.
    No preview · Article · Jul 2013 · Marine Ecology Progress Series
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    Full-text · Dataset · Jun 2013
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    ABSTRACT: In this study, we present and test the functioning of a automated multi-flume actograph that is able to simulate concomitant geophysical cycles (day-night and hydrodynamic cycles) characterizing the benthic environment of continental margins. The burrowing Norway lobster (Nephrops norvegicus, L.) was used to test the functioning of the device. The system is endowed with pumps and a pipe system for periodical current flow generation. Monochromatic blue light cycle (472 nm) was provided by submergible LED's lighting strips. Locomotor activity of 8 individuals was tracked by 4 HD video cameras during a 10 days trial. A customized automated video-imaging protocol in MATLAB calculated displacement of animals (cm/min). The functioning of the system was tested simulating an Atlantic continental shelf scenario (i.e. light intensity of 4 · 10−3 μE/m2/s and current flow at 10 cm/s). Robust time series outputs of nocturnal phase were reported, with the first laboratory evidence of the influence of current flow on burrow emergence of the species. Water flow increase inhibited lobster movement generating a dual reaction in relation to their burrow emergence phase. The method presented here could be pivotal to study unknown aspects of Norway lobster ecology.
    Full-text · Article · Jun 2013 · Journal of Experimental Marine Biology and Ecology

  • No preview · Dataset · May 2013
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    ABSTRACT: Seasonality in marine fish communities is usually studied by using different sampling techniques (e.g. visual census in shallow water or trawling in deeper areas) that are hard to perform over long periods with a high frequency of data recording. Furthermore, the coupling with fluctuations in key habitat parameters (e.g. light, temperature, salinity, and turbidity) is not a simple task to accomplish. Cabled video-observatories implemented with multiparametric sensors for habitat monitoring are allowing for the first time the continuous and long term recording of marine communities' dynamic (e.g. day-night, seasonal, and predator-prey fluctuations). In this scenario, the OBSEA video-cabled observatory has been recently deployed (2009) within a coastal area in the western Mediterranean Sea (Vilanova i la Geltrú -Spain) at a depth of 20 m. It is endowed with a video camera and a CTD. The OBSEA is located in a sandy area in which are placed numerous artificial reefs that protect the ground from trawling. The OBSEA is placed in front of one of these reefs. Accordingly, we report here only the preliminary results of this study consisting of one month video-monitoring at 30 min frequency of the local fish community in association with environmental fluctuations. In the future this analysis will cover an entire year. Waveform analysis was carried out in order to detect the occurrence of significant daily periodicity in species abundance, while time series of community fluctuations were related to environmental parameters (temperature and pressure at the sea bottom). In both cases particular attention was directed to interacting species such as predators and preys. Preliminary results highlight how cabled observatories could contribute to study community's dynamic. Finally, the analysis of the entire year observations will allow to study changes of the artificial reef community among different seasons. Moreover, the long term data from OBSEA could permit to evaluate possible climate changes effects on the local fish community.
    Full-text · Conference Paper · Mar 2013
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    ABSTRACT: The Citizen Science refers to the public participation in scientific activities and research projects related with environment and its biodiversity are taking advantage of new technologies such us internet and mobile phones with recording capabilities for an easy data collection and sharing. In this paper, we presented a Citizen Science experience with the OBSEA costal-cabled video-observatory, deployed in western Mediterranean in 2009. A local biodiversity survey is going to be conducted by citizens as generic non-experienced users, high-school students, and amateur divers helping to identify and classify fishes appearing within different digital products such as time-lapse images and footages. Accordingly, we implemented a protocol for the web-based species identification supervised by scientists, in order to evaluate the different performances for each group.
    Full-text · Conference Paper · Mar 2013
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    ABSTRACT: The Norway lobster is a burrowing decapod of elevated commercial importance for the European fishery. Understand which factors affect its diel (24-h based) catchability is of importance for its stock assessment. Here we presented preliminary results on burrow emergence modulation on lobsters exposed to water flow cycles in the laboratory simulating internal tides.
    Full-text · Dataset · Oct 2012
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    ABSTRACT: To adequately describe seasonal rhythms in habitat utilization by fish communities, observations are needed that occur at a relatively high frequency and over large temporal windows. For the first time, images collected from a cabled video-observatory (the western Mediterranean expandable SEAfloor OBservatory; OBSEA) were utilized to examine habitat utilization by coastal fishes. Over the course of a year, hourly digital images of the water column and an artificial reef were obtained during daylight hours. For each image, the total number of species, an estimate of the abundance of individuals, and the Shannon Diversity Index were quantified. A total of 22 fish species commonly associated with nearshore western Mediterranean habitats were identified, and significant spatial (water column vs. artificial reef), seasonal (spring, summer, autumn, and winter), and daily (morning, midday, and sunset) differences in habitat utilization occurred. Four species (Diplodus vulgaris, Diplodus cervinus, Diplodus sargus, and Scorpaena porcus) were associated with the artificial reef, while one species (Pagrus pagrus) chiefly occurred in the water column. Chromis chromis and Diplodus annularis occurred at the site more frequently in the winter and autumn, respectively, while 14 other species utilized the site more frequently in either the spring (8 spp) or summer (6 spp). In addition, Dentex dentex and Spicara maena occurred more frequently at sunset, while D. cervinus displayed a crepuscular rhythm (occurring more frequently in the morning and at sunset). Species diversity was highest in the summer and lowest in the winter. If not taken into account when planning in situ sampling, such seasonal and/or diel differences may lead to spurious estimates of population sizes and biodiversity. We suggest that cabled video-observatories offer a non-invasive and reliable technology for faunistic sampling and population assessment in coastal water of the Mediterranean and likely elsewhere.
    Full-text · Article · Aug 2012 · Journal of Marine Biology
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    ABSTRACT: All marine species studied thus far show rhythmic temporal patterns in their behavioural, physiological, and molecular functions, which are collectively known as biological rhythms. Biological rhythms are generated by biological clocks that time biological functions and are synchronized by geophysical cycles, such as the solar light-dark cycle and tidal cycle. On continental margins, behavioural rhythms can be detected by diel (i.e., 24-hour based) or seasonal periodical trawling as a consequence of massive inward and outward displacements of populations to and from the sample areas. As a result, significant errors in population/stock and biodiversity assessments performed by trawling may occur if timing of sampling is not taken into account. The increasing number of cabled and permanent multiparametric seafloor observatories now allows direct, continuous, and long-lasting monitoring of benthic ecosystems and analysis in relation to several habitat cycles. This review describes the adaptation of this technology to investigations of rhythmic behaviour by focusing on automated video imaging. Diel fluctuations in the number of video-observed individuals can be used as a measure of average population rhythmic behaviour. The potential implementation of automated video image analysis in relation to animal tracking and classification procedures based on the combined use of morphometric tools and multivariate statistics is detailed in relation to populational and community studies. Based on video cameras mounted at multiparametric cabled observatories, an integrated time-series analysis protocol using chronobiomedical procedures is proposed to place video-recorded bioinformation in an oceanographic context.
    Full-text · Article · Jun 2012

Publication Stats

3k Citations
158.96 Total Impact Points

Institutions

  • 1998-2014
    • Institut Marqués, Spain, Barcelona
      Barcino, Catalonia, Spain
    • University of California, Santa Barbara
      • Marine Science Institute
      Santa Barbara, California, United States
  • 1992-2013
    • Institut de Ciències del Mar
      Barcino, Catalonia, Spain
  • 2008-2010
    • Spanish National Research Council
      • Institute of Marine Sciences
      Madrid, Madrid, Spain
  • 2001
    • Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research
      Bremerhaven, Bremen, Germany