Towards intelligent aquaculture. Development of an early Biological Warning System to monitor exposure to contaminants and fish welfare: from artificial vision to systems modelling

161 p.Etorkizun hurbilera begira gizakion kopurua ez ezik (Gerland et al., 2014; United Nations, 2014), itsas elikagaien ekoizpenaren eta kontsumoaren hazkundea espero da. Azken honen hazkundeak, batipat, akuikulturak bideratuko du (German Advisory Council on Global Change - WBGU, 2013). Akuikultura, ekoizpena handiagotzeko helburuagaz, itsas organismoen hazkunde kontrolatua da. Bertatik lortzen diren produktuak era askotakoak izan daitezke: arrainak, moluskuak, krustazeoak, algak eta itsas landareak dira ezagunenak. Baina kokodriloak, dortokak eta beste motatako zenbait animalia urlehortarrak ere ekoizten dira. Era berean, akuikultura instalazioek kokapen desberdinak euki ditzakete: itsas kostaldean zein itsasadarretan baina lur barnean zein ibai edo lakuen ondoan ere aurkitu daitezke.Beste edozein ekoizpen prozesu bezala, sortzen diren produktuen kalitatea erronka garrantzitsuenetariko bat da. Eta kalitatea, kontuan izanda sortzen diren produktuak gizakion kontsumorako direla, ekoiztutako animalien osasungarritasunarekin bat doa. Kezkarik garrantzitsuenetarikoa itsas elikagaien ekoizpenean ur ingurugiroan dauden kutsatzatzaileek ekoiztutako produktuetan duten efektua da. Kutsatzaileak gero eta kantitate haundiagoetan azaltzen dira eta gainera, gero eta kutsatzaile berri gehiago agertzen dira (Bevan et al., 2012; Roose et al., 2011). Kutsatzaileak ez dira bakarrik uretara izurtzen, animaliei emoten zaien elikagaiak ere kutsatuta egon daitezke (Dahle et al., 2010; Dobson et al., 2008; Sharma and Paradakar, 2010). Hoierariko kutsatzaile askok ere, animalien ongizatean efektu negatiboak izaten dituzte eta galera ekonomiko haundiak sortarazten dituzte. Gaur egun, kutsatzaileak antzemateko metodo ez-inbasiboen galera dago. Hare eta gehiago, kutsatzaile berriak detektatzeko metodorik ez dago, antzemate metodoak kutsatzaile bakoitzeko ezpezifikoki diseinatsen direlako eta gero eta kutsatzaile berri gehiago detektatzen direlako, adibidez gizakion kontsumorako uran (Dahle et al., 2010; Roose et al., 2011).Tesi honek, monitorizazio metodologia ez inbasibo bat garatzen du non arrainak Alerta Sistema Biologikoa (Biological Warning System - BWS) giza erabiltzen dira. Arrainak, euren igeriketa jokabidea aztertuz, sensore bat balira kontzideratzen dira. Metodologia honen abantailarik esanguratsugarrienak dira: i) teknologia eskuragarria bideratzea, ii) monitorizazio on-line-a uzten duela eta iii) mota ezberdinetako kutsatzaileekin, ezagun ala ezezagun, lan egiteko ahalmena izango duela.Azkenik, proposatutako Alerta Sistema Biologikoa beste hierarkia handiagoko sistemekin egon beharko luke harremanetan eta sistema guzti hauen emaitzak ekoiztutako produktuen trazabilitate agiriekin batera joan beharko lukete azken produktuak merkatuara heltzerakoan. Hierarkia handiagoko sistema hauek Arrizku Analisis eta Punto Kritikoen Kontrol (Hazard Analysis and Critical Control Point - HACCP) eta Arrain Ongizate Segurtasun Sistemak (Fish Welfare Assurance System - FWAS) dira hain zuzen ere (van de Vis et al., 2012).HipotesiaTesi hau ondoko hipotesian oinarrituta dago:Arrain multzo batek sentsore biologiko bat izango balitz bezala jokatuko du; arrainen jokabidea, arrainen erantzun biologiko eta fisiologikoak batzen dituena, kanpo estimuluen aurrean modu ez inbasiboan neurtu daitekelako. Honek, arrain-sistemaren jokabidearen aldaketa on-line monitorizaziorako tresna gisa erabiltzea bideratzen du.Helburuak eta ekarpenakTesi honen helburu garrantzitsuena arrainak sentsore giza erabiliz, arrainen ongizatea on-line monitorizatzeko eta akuikultura industrian aplikatzeko tresna baten disenua eta eraikuntza da. Honetarako, jakintza alor anitzak jorratzen dira, hala nola biologia, etologia, ingurugiroaren ikuskaketa, arrainen ongizatea, elikagain kalitatearen fidagarritasuna, sistemen ingenieritza edota seinaleen prozesamendu ez-lineala.Lupia (Dicentrarchus labrax) izan da Tesi hau garatzeko aukeratutako arrain mota bi arrazoi nagusirengatik. Batetik, mediterraneo itsasoko herrialdeetako akuikultura produkzioan oso hedatuta dagoelako eta, aurrekoarekin loturik, lupiaren produkzioan arrainen ongizatearen eta azken produktuaren kalitatea oso garrantzitsua delako, gehienbat gizakion kontsumora bideraturiko produktua delako hain zuzen.Bigarren mailako helburuak, proposatutako tresnaren ebaluazioarekin lotuta egoteaz gain, diseinatutako sistemak aldagai ezberdinen menpean duen portaera aztertzen dute, hala nola:Arrain-sistemaren erantzuna arrain kopurua aldatuz.Arrain-sistemaren erantzuna arrainen dietari selenioa gehitzerakoan.Arrain-sistemaren erantzuna urari kutsatzaile neurotoxikoa den metilmekurioa gehitzerakoan.Hirugarren eta azken helburua, aurreko bi helburuen bitartez garatutako informazioa, ezagutza-eredu batetan isladatzearekin dator bat.Helburu hauekin loturik, Tesi honek ondoko ekarpenak ditu:Sistemen ingenieritzan oinarritutako lan metodologia berri bat garatu da.Ez-inbasiboa, moldakorra, merkea eta Alerta Sistema Biologiko sistema batetan egokitzeko gai den irudi analisian oinarritutako tresna bat garatu da.Perturbazio bati erantzunez arrain multzoaren mugimendu ereduan oinarrituriko sentsore bat garatu da.Arrainen multzoaren igeriketa ereduari aplikatu ahal zaizkion zenbait seinale prozesaketa metodo ez-lineala garatu dira.Arrainen erantzuna kanpotiko perturbazio baten aurrean modelatzen duen eredu matematikoa garatu da.Garatutako metodologia eta monitorizazio tresna zenbait kasu experimentaletan aztertu da.Ikerketa MetodologiaIkerketa metodologiaren aldetik, Glass-ek (1995) proposatutako pausu berdinak jarraitu dira. Honela, Tesia lau faseetan banaturik dago: jakinarazte fasea, fase proposizionala, fase analitikoa eta ebaluaketa fasea. Era berean, erabilitako metodologia zati zientifiko eta zati enpiriko baten batura da. Ikerketa metodologia honek erdiesten dituen onurak ondokoak dira:Erabilitako ikerketa metodologia arrainen multzoak eta bere ingurugiroak osatzen duten sistemaren dinamika ulertzeko ezin bestekoa izan da.Tesian garatuta tresna zenbait kasu partikularretan aztertu da. Honela, tresnaren onurak ez ezik bere mugak ere aztertu ahal izan dira.Garatutako tresna benetako akuikultura instalazio batetan inplementatzeko bideragarritasuna aztertu da Norbegiako ¿Centre for Autonomous Marine Operations and Systems (AMOS)¿ Ikerketa Zentruan hiru hilabeteko ikerketa egonaldiari esker. Egonaldia Europa Batasuneko ikerlari mugikortasun beka batekin finantziatu da ¿European Economic Area (EEA) Researcher Mobility and Co-operation Grant, NILS Science and Sustainability Programme.Publikatutako lanen maila, kalitatea eta irismena handiagotu da.Etorkizunean, ikerketa proiektu eta gertaeretan parte hartzeko ahalmenaren handiagotzea, ikerlariaren kontaktu sarearen handiagotzearekin batera.Azkenik, Tesiaren zati experimentalak Yin-en (1993) kasu-ikerketaren oinarriak jarraitzen ditu. Kasu-ikerketa metodoa ezagutza induktiboa sortzeko erabiltzen da eta eguneroko gertakari erreal eta komplexuei aplikatzerakoan baliagarritasun handia erakusten du.Lanaren GarapenaTesi honen lehenengo zatian, irudi analisian oinarritutako metodologia ez-inbasibo bat garatzen da. Metedologia hau, video grabaketa, irudi prozesaketa eta seinale ez-linealen analisi eta prozesaketan datza. Arrain multzoaren erantzuna gertaera estokastiko edo aleatorio baten aurrean aztertzen eta neurtzen da. Irudietan agertzen diren objetuen antzematea, fluxu optikoko algoritmo baten bitartez burutzen da. Honela arrainak detektatu ez ezik, irudien atzealdea eta bestelako efektu ez desiratuak ezabatzen dira. Azkenik, arrain multzoaren zentruak jarraitzen duen ibilbidea, Shannon (Shannon, 1951, 1948) eta permutazio entropia (Bandt and Pompe, 2002) batetik; eta Higuchi (1988), Katz (1988) eta Castiglioni-k (2010) proposatutako Katz algoritmoaren aldaketaren bitartezko dimentsio fraktal algoritmoez aztertzen da.Garatutako monitorizazio tresna hiru kasu partikularretan aztertu zen. Lehenengoan, hiru lupia multzo aztertu ziren. Horietariko bi antzekoak ziren (kontrolak eta elastomero batekin markatutakoak), eta hirugarrena aldiz, 9 egunez metilmerkuriodun (4 µg MeHg/L) uretan murgildutako arrainez osoturik zegoen. Shannon-en entropia eta Katz-Castiglioni-ren algoritmoek izan ziren emaitza onenak erakutzi zutenak. Esan daiteke biek, arrainen erantzunak modu ez inbasibo batean kuantifikatzeko garaian, ahalmen nahikoa erakutsi zutela. Hala ere, Katz-Castiglioni-ren algoritmoak Shannon-en entropia baino askoz ere pisu konputazional handiagoa erakutsi zuen.Hasiera baten, arrain multzoa osotzen zuten animalien kopurua inolako eraginik euki zitzakela animalia sistema osoaren jokabidean garatutako aztertze metodologiari dagokionez, ez zen uste. Honetan sakontzeko, bigarren kasu partikular bat diseinatu zen, non sistemako aldagai bakarra arrain kopurua zen. Bigarren kasu partikular honen helbururik garrantzitsuena sistemarentzako Lan Puntuaren zehazpena zen, hau da, arrainek inolako perturbazio barik daudeneko egoera dinamikoa. Monitorizazio tresna doitzeko eta perturbazioak egoera ¿normaletik¿ bereiztu ahal izateko, Lan Puntuaren zehazpena ezin bestekoa da. Honetarako bi experimentu disenatu ziren:Arrain kopuruaren murrizketa. Arrain kopurua 50etik 1era pasatu zen 4 asteren buruan (50, 25, 13 eta arrain 1 aste bakoitzeko).Arrain kopururaren hazkuntza. Sistema osotzen duten arrainen kopurua 1etik 5era hazi zen egunero arrain berri bat sartuz (1, 2, 3, 4 eta 5 arrain egun bakoitzeko).Hirugarren kasu partikularrean, aldiz, arrainen urari bi sustantzia ezberdin gehitu zitzaizkion. Batetik, sodio selenitoa (Na2SeO3, 10 µg/L) gehitu zitzaion 7 egunen zehar eta bestetik metilmerkurioa (4 µg MeHg/L) 14 egunen zehar.Tesiaren azken atalean, aurreko kasuetan garatutako jakituriarekin ezagutza eredu bat eraiki da. Eredua, 3 azpi-ereduez osatuta dago, zeintzuk sistemaren eguneroko erantzuna eta Shannon-en entropiaren emaitzak, egoera basalean, gertaera aleatorio bateri erantzunez eta azken bien arteko erlazioari begira, integratzen dituzte.OndorioakOndoren Tesiaren ondoriorik esanguratsuenak adierazten dira:Arrainen monitorizaziorako tresna garatu da. Tresnaren oinarrian irudi eskuraketa eta prozesaketa egoteaz gain, arrain multzoak osatzen duen zentruaren ibilbidearen analizi ez-lineala ere badago.Arrainen sistemaren dinamika aztertzeko garaian Shannon-en entropia parametrorik onena izan da.1 eta 5 arrainen artean, lubia arrain sistemaren Shannon-en entropia eta sistema osotzen duten arrain kopuruaren erlazioa oso estua da.Lubia arrain sistemaren eta Shannon-en entropiaren arteko erlazioa exponentziala da.Garatutako tresna kasu partikularrei aplikatzerakoan era egokian lan egin du. Honek, ikerketa lanaren hasierako Tesia berretsi du.Espero zen bezala eta garatutako tresnak konfirmatuta, urari gehitutako sodio selenito kontsentrazioak ez du inolako efekturik izan lubia sistemaren Shannon-en entropian.Era berean, garatutako tresnak konfirmatu du urari gehituriko metilmerkurioak efektu ezezkorra izan duela lubia sistemaren Shannon-en entropian.Tresnaren aplikazioak kasu partikularretan lubia sistemaren Shannon-en entropiaren eguneroko balioa ez ezik bere egunean-eguneko bilakaera kontutan hartu behar dela erakutsi du.Garatutako ezagutza eredua lubia arrain sistemaren jokabide erantsunaren eguneroko bilakaeran oinarrituriko 3 azpi-ereduz osoturik dago: Azpi-eredu basala, gertaera aleatorioaren erantzuneko azpi eredua eta aurreko biak erlazionatzen dituen azpi-eredua.Garatutako tresna, zenbait hobekuntzekin, on-line monitorizazio arkitektura batetan inplementatzeko gaitasuna duela esan daiteke. Eta beraz, era basatian nahiz akuikulturan, arrain multzoak monitorizatzeko edo/eta ur kutsadura antzemateko ingurumen-programetan tresna baliagarria izan daiteke.Beraz, ikerketa lan honen Tesia arrainak sentsore biologiko moduan erabil daitezkela da; kanpo perturbazioen eraginez euren portaeran agertzen diren aldaketak modu ez-inbasiboan neurtu daitezkelako.Gerorako LanaGaur egun Errezirkulazio Akuikultura Sistemek (Recirculating Aquaculture Systems - RAS) gero eta aplikazio handiagoa dute munduan zehar. Tesi honetan oinarrituriko teknologia baten garapenak zekulako erabilgarritasuna eukiko luke mota honetako sistemetan, batez ere, produkzio unitate osoa monitorizatu daitekelako. Era berean, ur kutsadura antzemateko ingurumen-programetan tresna baliagarria izan daiteke. Azken honetarako, teknologia honetan oinarrituriko ikusketa guneak garatu beharko lirateke.Urpean lan egiteak desabantail ugari ditu. Hau ekiditeko datu eskuraketa teknika ezberdinak aztertu beharko lirateke, hala nola izpi-infragorriak, sonar teknologia edota irudi hiperespektralak zenbait esatearren.Azkenik, teknologia honetatik lortutako datuak bestelako tekniken bidez lorturiko datuekin bat egin beharko lirateke. Honela, arrainen datu biokimiko, histologiko eta fisiologikoez gain, teknika ez-inbasiboen bidez neurtutako igeriketa jokabideak ere kontutan hartu beharreko parametroa izan beharko luke.Research Center for Experimental Marine Biology and Biotechnology - Plentzia Marine Station (PiE

Non-Linear Analyses of Fish Behaviours in Response to Aquatic Environmental Pollutants—A Review

Analysis of fish behaviour is an effective way to indirectly identify the presence of environmental pollutants that negatively affect fish life, its production and quality. Monitoring individual and collective behaviours produces large amounts of non-linear data that require tailor-suited computational methods to interpret and manage the information. Fractal dimension (FD) and entropy are two groups of such non-linear analysing methods that serve as indicators of the complexity (FD) and predictability (entropy) of the behaviours. Since behavioural complexity and predictability may be modulated by contaminants, the changes in its FD and entropy values have a clear potential to be embedded in a biological early warning system (BEWS), which may be particularly useful in Precision Fish Farming settings and to monitor wild populations. This work presents a review of the effects of a wide range of environmental contaminants, including toxic compounds, cleaning and disinfecting agents, stimulant (caffeine), anaesthetics and antibiotics, heavy metals (lead, cupper, and mercury), selenium, pesticides and persistent environmental pollutants, on the FD and entropy values of collective and individual behavioural responses of different fish species. All the revised studies demonstrate the usefulness of both FD and entropy to indicate the presence of pollutants and underline the need to consider early changes in the trend of the evolution of their values prior to them becoming significantly different from the control values, i.e., while it is still possible to identify the contaminant and preserve the health and integrity of the fish.The work was supported by the Spanish Ministerio de Economía y Competitividad MINECO (Grant RTC-2014–2837-2 “SELATUN: Minimización de la problemática del mercurio del atún y valorización del atún como alimento saludable, Programa Retos-Colaboración 2014”. The funding source had no involvement in the preparation of this manuscript. I. Martinez is supported by IKERBASQUE (Basque Foundation for Science)

Entropy and Fractal Techniques for Monitoring Fish Behaviour and Welfare in Aquacultural Precision Fish Farming—A Review

In a non-linear system, such as a biological system, the change of the output (e.g., behaviour) is not proportional to the change of the input (e.g., exposure to stressors). In addition, biological systems also change over time, i.e., they are dynamic. Non-linear dynamical analyses of biological systems have revealed hidden structures and patterns of behaviour that are not discernible by classical methods. Entropy analyses can quantify their degree of predictability and the directionality of individual interactions, while fractal dimension (FD) analyses can expose patterns of behaviour within apparently random ones. The incorporation of these techniques into the architecture of precision fish farming (PFF) and intelligent aquaculture (IA) is becoming increasingly necessary to understand and predict the evolution of the status of farmed fish. This review summarizes recent works on the application of entropy and FD techniques to selected individual and collective fish behaviours influenced by the number of fish, tagging, pain, preying/feed search, fear/anxiety (and its modulation) and positive emotional contagion (the social contagion of positive emotions). Furthermore, it presents an investigation of collective and individual interactions in shoals, an exposure of the dynamics of inter-individual relationships and hierarchies, and the identification of individuals in groups. While most of the works have been carried out using model species, we believe that they have clear applications in PFF. The review ends by describing some of the major challenges in the field, two of which are, unsurprisingly, the acquisition of high-quality, reliable raw data and the construction of large, reliable databases of non-linear behavioural data for different species and farming conditions.The work was supported by the Spanish MINECO (Grant RTC-2014–2837-2- “SELATUN: Minimización de la problemática del mercurio del atún y valorización del atún como alimento saludable, Programa Retos-Colaboración 2014”. The funding source had no involvement in the preparation of this manuscript

The Shannon Entropy Trend of a Fish System Estimated by a Machine Vision Approach Seems to Reflect the Molar Se:Hg Ratio of Its Feed

The present study investigates the suitability of a machine vision-based method to detect deviations in the Shannon entropy (SE) of a European seabass (Dicentrarchus labrax) biological system fed with different selenium: mercury (Se:Hg) molar ratios. Four groups of fish were fed during 14 days with commercial feed (control) and with the same feed spiked with 0.5, 5 and 10 mg of MeHg per kg, giving Se: Hg molar ratios of 29.5 (control-C-1); 6.6, 0.8 and 0.4 (C-2, C-3 and C-4). The basal SE of C-1 and C-2 (Se:Hg > 1) tended to increase during the experimental period, while that of C-3 and C-4 (Se:Hg < 1) tended to decrease. In addition, the differences in the SE of the four systems in response to a stochastic event minus that of the respective basal states were less pronounced in the systems fed with Se: Hg molar ratios lower than one (C-3 and C-4). These results indicate that the SE may be a suitable indicator for the prediction of seafood safety and fish health (i.e., the Se: Hg molar ratio and not the Hg concentration alone) prior to the displaying of pathological symptoms. We hope that this work can serve as a first step for further investigations to confirm and validate the present results prior to their potential implementation in practical settings.We wish to thank Grupo Tinamenor (Cantabria, Spain) for providing the European seabass. Jose Antonio Carrero, of the Department of Analytical Chemistry of the University of the Basque Country, UPV-EHU, measured the concentrations of Hg and Se in the feeds by ICP-MS. The work was supported by grants from the Spanish MINECO (RTC-2014-2837-2-"SELATUN: Minimizacion de la problematica del mercurio del atun y valorizacion del atun como alimento saludable, Programa Retos-Colaboracion 2014" and CTM2012-40203-C02-01-"BMW: Biomarcadores estandar de base cientifica en mejillon para diagnosticar y monitorizar los efectos biologicos de la polucion en el Golfo de Bizkaia: implementacion de la DEME"), Euskampus Fundazioa-Campus of International Excellence (307615SAA2) and from the Basque Government Elkartek Grant KK-2016/00057-"MAROMEGA: Nuevas alternativas para la produccion de omega-3 a partir derecursos marinos". The funding sources had no involvement in the preparation of this manuscript. We would like to express our gratitude to the three anonymous reviewers for their useful comments in order to improve this manuscript

Iridescent Cellulose Nanocrystal Films: the Link Between Structural Colour and Bragg's Law

Structural colour is a phenomenon found in nature, which provides plants and animals with vibrant optical properties. The production of this colour is based on the interaction of incident light with the hierarchical organisation of submicron- and micron-sized layered structures. Cellulose nanocrystals (CNCs) are anisotropic building units formed by acid hydrolysis of native cellulose microfibers, which can disperse in aqueous media to form a photonic liquid crystal. One fascinating example of the appearance of biomimetic colour is the supramolecular assembly of CNCs into iridescent layered structures that rotate along a helical screw to yield a long-range chiral nematic order. A quick, simple and engaging experiment that allows the establishment of a direct relation between the structural colour and underlying mechanism of the light interaction with these hierarchically structured materials is reported. The obtained colour changes are explained within the theoretical framework provided by Bragg's law and may provide an easy way to observe the macroscopic manifestation of this often abstract concept

Shannon Entropy in a European Seabass (Dicentrarchus labrax) System during the Initial Recovery Period after a Short-Term Exposure to Methylmercury

Methylmercury (MeHg) is an environmental contaminant of increasing relevance as a seafood safety hazard that affects the health and welfare of fish. Non-invasive, on-line methodologies to monitor and evaluate the behavior of a fish system in aquaculture may make the identification of altered systems feasible-for example, due to the presence of agents that compromise their welfare and wholesomeness-and find a place in the implementation of Hazard Analysis and Critical Control Points and Fish Welfare Assurance Systems. The Shannon entropy (SE) of a European seabass (Dicentrarchus labrax) system has been shown to differentiate MeHg-treated from non-treated fish, the former displaying a lower SE value than the latter. However, little is known about the initial evolution of the system after removal of the toxicant. To help to cover this gap, the present work aims at providing information about the evolution of the SE of a European seabass system during a recuperation period of 11 days following a two-week treatment with 4 mu g center dot MeHg/L. The results indicate that the SE of the system did not show a recovery trend during the examined period, displaying erratic responses with daily fluctuations and lacking a tendency to reach the initial SE values.We wish to thank Grupo Tinamenor (Cantabria, Spain) for providing the European sea bass, Urtzi Izagirre for his contribution to the design of the experimental treatments, and Xabier Lekube and Gregor Bwye for technical assistance. The work received financial support from the Spanish Ministry of Economy and Competitiveness Project number: CTM2012-40203-C02-01, Towards science-based standard biomarker methods, suitable to diagnose and monitor pollution biological effects in the Bay of Biscay for the purpose of implementing the European Marine Strategy Framework Directive-BMW and Project number: RTC-2014-2837-2, Minimizacion de la problematica del mercurio del atun y valorizacion del atun como alimento saludable-SELATUN

Antioxidant activities and selenogene transcription in the european sea bass (Dicentrarchus labrax) liver depend, in a non-linear manner, on the Se/Hg molar tatio of the feeds

[EN] Feeding 3.9 and 6.7 mg Hg/kg (Se/Hg molar ratios of 0.8 and 0.4, respectively) for 14 days negatively affected Dicentrarchus labrax growth and total DNTB- and thioredoxin-reductase (TrxR) activities and the transcription of four redox genes (txn1, gpx1, txnrd3, and txnrd2) in the liver, but a diet with 0.5 mg Hg/kg (Se/Hg molar ratio 6.6) slightly increased both reductase activities and the transcription of txn1, gpx1, and txnrd2. Feeding 6.7 mg Hg/kg for 53 days downregulated the genes of the thioredoxin system (txn1, txnrd3, and txnrd2) but upregulated gpx1, confirming the previously proposed complementarity among the antioxidant systems. Substitution of 20% of the feed by thawed white fish (hake) slightly counteracted the negative effects of Hg. The effects were not statistically significant and were dependent, in a non-linear manner, on the Se/Hg molar ratio of the feed but not on its Hg concentration. These results stress the need to consider the Se/Hg molar ratio of the feed/ food when evaluating the toxicity of Hg.The work was supported by grants from the Spanish MINECO (RTC-2014–2837-2- “SELATUN: Minimización de la problemática del mercurio del atún y valorización del atún como alimento saludable, Programa Retos-Colaboración 2014” and CTM2012-40203-C02-01- “BMW: Biomarcadores estándar de base científica en mejillón para diagnosticar y monitorizar los efectos biológicos de la polución en el Golfo de Bizkaia: implementación de la DEME”), Euskampus Fundazioa- Campus of International Excellence (307615SAA2), and from the Basque Government Elkartek Grant KK-2016/00057- “MAROMEGA: Nuevas alternativas para la producción de omega-3 a partir de recursos marinos.” The funding sources had no involvement in the preparation of this manuscript

Antioxidant activities and selenogene transcription in the European sea bass (Dicentrarchus labrax) liver depend, in a non-linear manner, on the Se/Hg molar ratio of the feeds

Feeding 3.9 and 6.7 mg Hg/kg (Se/Hg molar ratios of 0.8 and 0.4, respectively) for 14 days negatively affected Dicentrarchus labrax growth and total DNTB- and thioredoxin-reductase (TrxR) activities and the transcription of four redox genes (txn1, gpx1, txnrd3, and txnrd2) in the liver, but a diet with 0.5 mg Hg/kg (Se/Hg molar ratio 6.6) slightly increased both reductase activities and the transcription of txn1, gpx1, and txnrd2. Feeding 6.7 mg Hg/kg for 53 days downregulated the genes of the thioredoxin system (txn1, txnrd3, and txnrd2) but upregulated gpx1, confirming the previously proposed complementarity among the antioxidant systems. Substitution of 20% of the feed by thawed white fish (hake) slightly counteracted the negative effects of Hg. The effects were not statistically significant and were dependent, in a non-linear manner, on the Se/Hg molar ratio of the feed but not on its Hg concentration. These results stress the need to consider the Se/Hg molar ratio of the feed/food when evaluating the toxicity of Hg.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. The work was supported by grants from the Spanish MINECO (RTC-2014–2837-2- “SELATUN: Minimización de la problemática del mercurio del atún y valorización del atún como alimento saludable, Programa Retos-Colaboración 2014” and CTM2012-40203-C02-01- “BMW: Biomarcadores estándar de base científica en mejillón para diagnosticar y monitorizar los efectos biológicos de la polución en el Golfo de Bizkaia: implementación de la DEME”), Euskampus Fundazioa-Campus of International Excellence (307615SAA2), and from the Basque Government Elkartek Grant KK-2016/00057- “MAROMEGA: Nuevas alternativas para la producción de omega-3 a partir de recursos marinos.

Nola aurre egin itsas garraioak eragindako klima-aldaketari? Estrategia berriak

Currently maritime transport is growing due to globalization and economic growth, and it transports approximately the 90% of the world’s goods. World maritime transport fleet is increasing in amount and in size of vessels and, accordingly, marine fuel oil consumption is also increasing. The marine fuel oil consumption represents the 50% of the operational costs of a vessel and it has a huge environmental impact (ocean acidification, pollution, greenhouse effect, climate change…). Consequently, IMO (International Maritime Organization) created a specific environmental regulation and divided the ocean in different ECA zones (Emission Control Areas). The present work analyses the best strategy, a shipowner should adopt, to comply with ECA regulations, in three different panoramas: i) using an active vessel, placing a scrubber or consuming low sulphur marine fuel oil; ii) constructing a new vessel, choosing between marine dual engine or marine diesel mengine in both cases with or without scrubber; and iii) in case new ECA zones are created, which affects directly the vessel’s operational area.; Gaur egun, itsas garraioak munduko ondasunen % 90 mugitzen du. Ekonomiaren hazkundea eta globalizazioa direla-eta, garraio mota hori goraka doa. Munduko garraioontzi flotaren kopurua haziz doan neurrian, fuel-olioaren kontsumoa ere hazten ari da. Fuel-olioaren kostua garraio-ontzi baten kostu operazionalen % 50 baino gehiago da, eta erregai horren erabilerak eragin nabarmena du ingurumenean (azidifikazioa, kutsadura, berotegi-efektua…); hori kontuan izanik, ECA direlako guneetan (Emission Control Areas) banatu ditu munduko itsasoak IMOk (International Maritime Organization), ingurumen-legedi berezi baten pean. Artikulu honetan, aztergai da zer estrategia jarraitu behar duen armadore batek (itsasontzi baten ustiatzaileak) lege sorta horietara egokitzeko, honako hiru aldagai hauek kontutan izanda: i) eraikita dagoen itsasontzi bat ustiatzen badu, sufre gutxiagoko fuelak erabiltzea edo itsasontziaren motorra egokitzea; ii) itsasontzi berri bat eraikitzera badoa, motor duala edo diesel-motorra jartzea; eta iii) zer aukera dagoen IMOk ECA gune berriak sortzeko

SETApp: A machine learning and image analysis based application to automate the sea urchin embryo test

[EN] Since countless xenobiotic compounds are being found in the environment, ecotoxicology faces an astounding challenge in identifying toxicants. The combination of high-throughput in vivo/in vitro bioassays with high-resolution chemical analysis is an effective way to elucidate the cause-effect relationship. However, these combined strategies imply an enormous workload that can hinder their implementation in routine analysis. The purpose of this study was to develop a new high throughput screening method that could be used as a predictive expert system that automatically quantifies the size increase and malformation of the larvae and, thus, eases the application of the sea urchin embryo test in complex toxicant identification pipelines such as effect-directed analysis. For this task, a training set of 242 images was used to calibrate the size-increase and malformation level of the larvae. Two classification models based on partial least squares discriminant analysis (PLS-DA) were built and compared. Moreover, Hierarchical PLS-DA shows a high proficiency in classifying the larvae, achieving a prediction accuracy of 84 % in validation. The scripts built along the work were compiled in a user-friendly standalone app (SETApp) freely accessible at https://github.com/UPV-EHU-IBeA/SETApp. The SETApp was tested in a real case scenario to fulfill the tedious requirements of a WWTP effect-directed analysis.Authors gratefully acknowledge financial support from the Agencia Estatal de Investigación (AEI) of Spain and the European Regional Development Fund through project CTM2017–84763-C3–1-R and the Basque Government through the financial support as a consolidated group of the Basque Research System (IT1213–19). Iker Alvarez is grateful to the University of the Basque Country and the Université de Pau et des Pays de L′ Adour for his cotutelle predoctoral scholarship