Trophic pathways of an expanding pelagic fish species in the Mediterranean

Adapting to Global Change in the Mediterranean Hotspot, 18-20 September 2013, Sevilla.- 1 page, 2 figuresGlobal change has been recognized as the main driver of the expansion of species outside to their native range. How expanding species manage trophic resources may be the most critical factor to ensure survival and reproduction and one of the most important ways to impact native communities. [...]The work was funded by ECOTRANS Project (CTM2011-26333; Spanish Ministry of Economy and Competitiveness)Peer Reviewe

Feeding ecology and trophic position of three sympatric demersal chondrichthyans in the northwestern Mediterranean

14 pages, 5 figures, 3 tables, supplementary material http://dx.doi.org/10.3354/meps11188Understanding how marine predators interact is a scientific challenge. In marine ecosystems, segregation in feeding habits has been largely described as a common mechanism to allow the coexistence of several competing marine predators. However, little is known about the feeding ecology of most species of chondrichthyans, which play a pivotal role in the structure of marine food webs worldwide. In this study, we examined the trophic ecology of 3 relatively abundant chondrichthyans coexisting in the Mediterranean Sea: the blackmouth catshark Galeus melastomus, the velvet belly lanternshark Etmopterus spinax and the rabbit fish Chimaera monstrosa. To examine their trophic ecology and interspecific differences in food habits, we combined the analysis of stomach content and stable isotopes. Our results highlighted a trophic segregation between C. monstrosa and the other 2 species. G. melastomus showed a diet composed mainly of cephalopods, while E. spinax preyed mainly on shrimps and C. monstrosa on crabs. Interspecific differences in the trophic niche were likely due to different feeding capabilities and body size. Each species showed different isotopic niche space and trophic level. Specifically, C. monstrosa showed a higher trophic level than E. spinax and G. melastomus. The high trophic levels of the 3 species highlighted their important role as predators in the marine food web. Our results illustrate the utility of using complementary approaches that provide information about the feeding behaviour at short (stomach content) and long-term scales (stable isotopes), which could allow more efficient monitoring of marine food-web changes in the study areaM.A.-P. was supported by a predoctoral fellowship of the FPI program (Spanish Ministry of Economy and Competitiveness). J.N. was supported by a research contract of the Marie Curie GIC project BioWeb. M.C. and J.A. are supported by a post-doctoral contract of the Ramon y Cajal Program (Spanish Ministry of Economy and Competiveness), and M.C. was also supported by BioWeb project. This study is a contribution to the project ECOTRANS (CTM2011-26333, Ministerio de Economía y Competitividad, Spain)Peer Reviewe

Changes in Life History Traits of Small Pelagic Fish in the Western Mediterranean Sea

21 pages, 8 figures, 3 tables, supplementary material https://www.frontiersin.org/articles/10.3389/fmars.2021.570354/full#supplementary-material.-- Data Availability Statement: The datasets presented in this article are not readily available because the dataset is available by request to the Spanish Institute of Oceanography. Requests to access the datasets should be directed to [email protected] pelagic fish (SPF) in the western Mediterranean Sea are key elements of the marine food web and are important in terms of biomass and fisheries catches. Significant declines in biomass, landings, and changes in the age/size structure of sardine Sardina pilchardus and anchovy Engraulis encrasicolus have been observed in recent decades, particularly in the northern area of the western Mediterranean Sea. To understand the different patterns observed in SPF populations, we analyzed key life history traits [total length at age, length at maturity, gonadosomatic index (GSI), and body condition (Kn)] of sardine and anchovy collected between 2003 and 2017, from different fishing harbors distributed along a latitudinal gradient from northern to southern Spain. We used Generalized Linear Models (GLM) to estimate the length at maturity and Generalized Additive Models (GAMs) to test the relationship with environmental variables (seawater temperature, water currents, and net primary productivity). The life history traits of both species presented seasonal, interannual and latitudinal differences with a clear decline in length at age, length at first maturity, and body condition, for both species in the northern part of the study area. In the southern part, on the contrary, life history traits did not present a clear temporal trend. The environmental conditions partially explained the long-term changes in life history traits, but the selected variables differed between areas, highlighting the importance of regional oceanographic conditions to understand the dynamics of small pelagic fish. The truncated length-at-age pattern for both species with the disappearance of the larger individuals of the population could have contributed to the poor condition of small pelagic fish populations in the northern part of the western Mediterranean Sea in recent years. In the south area, recent declines in body condition for sardine and anchovy were observed and could be a possible first sign for future population declines. This study highlights the importance of understanding the trade-off between the energy invested in reproduction, maintenance and growth at seasonal and interannual level to advance our knowledge on how environmental and human pressures influence population dynamics of small pelagic fish at local and regional scalesThis study was carried out within the Spanish Research project PELWEB (CTM2017-88939-R) funded by Spanish Ministry of Science, Innovation and Universities and the European Research Contract SPELMED (SC NR 02-TENDER EASME/EMFF/2016/032XXX) funded by EC EASME. Fisheries data collection has been co-funded by the EU through the European Maritime and Fisheries Fund (EMFF) within the National Program of collection, management and use of data in the fisheries sector and support for scientific advice regarding the Common Fisheries Policy (Regulation, EU 2017/1004)With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)Peer reviewe

Eco-socio-economic vulnerability assessment of Portuguese fisheries to climate change

Understanding ecological, and socio-economical vulnerabilities is fundamental towards developing and implementing regional adaptation strategies to climate change. The Portuguese coast is situated in a transition zone between temperate ecosystems to the north, and subtropical with Mediterranean characteristics, to the south, with distinct oceanographic regions (north, centre, and south), fish assemblages and socioeconomic realities of fish communities across these regions. We develop a framework to assess fisheries climate vulnerability in each port. A total of 32 ecological and socio-economic indicators were used to measure exposure, sensitivity, and adaptive capacity of the fishing sector to climate change by combining i) environmental projections ii) information from fishing communities (surveys at ports) and iii) landings and socio-economic data from official statistics offices. The vulnerability to climate change across regions, and its expected impact on fishing fleets and local communities, was low-moderate. Such information will enable fishing communities and decision makers to respond to expected climate change effects and direct/indirect associated activities. This framework comprises background information for developing mandatory EU climate adaptation plans that aim to improve the resilience of fisheries socio-economic systemsFundação para a Ciência e a Tecnologia | Ref. UIDB/04326/2020Fundação para a Ciência e a Tecnologia | Ref. UIDP/04326/2020Fundação para a Ciência e a Tecnologia | Ref. LA/P/0101/2020Fundação para a Ciência e a Tecnologia | Ref. SFRH/BD/11426/2022Ministerio de Ciencia e Innovación | Ref. FJC2020–043449-IFundação para a Ciência e a Tecnologia | Ref. SFRH/BD/06336/202Fundação para a Ciência e a Tecnologia | Ref. DL57/2016/CP1361/CT0008Fundação para a Ciência e a Tecnologia | Ref. 2022.04803.CEECINDPortugal 2020 | Ref. SAICT-45-2017-02Portugal 2020 | Ref. ALG-01-0145-FEDER-028518Portugal 2020 | Ref. PTDC/ASP-PES/28518/2017MAR2020-FEAMP | Ref. MAR-01.03.02-FEAMP-005

Ecological sensitivity and vulnerability of fishing fleet landings to climate change across regions

The degree of exposure of fishing communities to environmental changes can be partially determined by the vulnerability of the target species and the landings composition. Hence, identifying the species that ecologically most contribute to the vulnerability of the landings are key steps to evaluate the risk posed by climate change. We analyse the temporal variability in intrinsic sensitivity and the ecological vulnerability of the Portuguese fisheries landings, considering the species proportions derived both from the weights and revenues. To account for the diversification of species of each fleet, we explored the species dependence of the fishery in combination with the vulnerability of them. The analyses were carried out separately for three fleet typologies and three regions. Opposite to what has been observed at a global scale, the ecological sensitivity of the fisheries landings between 1989 and 2015 did not display a decline across areas or fishing fleets. Considering each fleet independently, for trawling, where average vulnerability was lower than in the other fleets, the sensitivity of the landings increased since the 2000s. On the other hand, the high vulnerability found in multi-gear fleets was compensated by diversification of the species caught, while purse-seine fleets targeted low vulnerability species but presented a high fishery dependence on few species. The results highlight the importance of combining information on ecological vulnerability and diversification of fishing resources at a regional scale while providing a measure of the ecological exposure to climate change.info:eu-repo/semantics/publishedVersio

Sardines at a junction: seascape genomics reveals ecological and oceanographic drivers of variation in the {NW} Mediterranean Sea

By evaluating genetic variation across the entire genome, one can address existing questions in a novel way while raising new ones. The latter includes how different local environments influence adaptive and neutral genomic variation within and among populations, providing insights into local adaptation of natural populations and their responses to global change. Here, under a seascape genomic approach, ddRAD data of 4609 single nucleotide polymorphisms (SNPs) from 398 sardines (Sardina pilchardus) collected in 11 Mediterranean and one Atlantic site were generated. These were used along with oceanographic and ecological information to detect signals of adaptive divergence with gene flow across environmental gradients. The studied sardines constitute two clusters (FST = 0.07), a pattern attributed to outlier loci, highlighting putative local adaptation. The trend in the number of days with sea surface temperature above 19°C, a critical threshold for successful sardine spawning, was crucial at all levels of population structuring with implications on the species' key biological processes. Outliers link candidate SNPs to the region's environmental heterogeneity. Our findings provide evidence for a dynamic equilibrium in which population structure is maintained by physical and ecological factors under the opposing influences of migration and selection. This dynamic in a natural system warrants continuous monitoring under a seascape genomic approach that might benefit from a temporal and more detailed spatial dimension. Our results may contribute to complementary studies aimed at providing deeper insights into the mechanistic processes underlying population structuring. Those are key to understanding and predicting future changes and responses of this highly exploited species in the face of climate change

Trophic niche segregation between sympatric chondrichthyes

Trabajo final presentado por Marta Albo Puigserver para el Máster en Ciencias Marinas: Oceanografía y Gestión del Medio Marino de la Universitat de Barcelona (UB), realizado bajo la dirección del Dr. Joan Navarro Bernabé del Institut de Ciències del Mar (ICM-CSIC).-- 29 pages[EN] Understanding how marine predators are structured and how they interact is a scientific challenge. Nowadays, to learn about trophic niche segregation, ecologists use two complementary methodologies, stomach content and isotopic analysis. The aim of this study was to examine the trophic ecology of three chondrichthyans (velvet belly lanternshark, blackmouth catshark and rabbitfish) that are common on discards of the Gulf of Lion (NW Mediterranean). For each species, we examined the diet of each species and the potential differences in diet between sexes, depths and individuals. We combined two methodologies; the analysis of stomach content (%N and %FO) and the analysis of stable isotope to perform Bayesian isotopic mixing models (combining isotopic values of predators and prey). We also calculated the trophic levels of each species. Our results showed a clear segregation between rabbitfish and the other two species. Rabbitfish showed a diet mainly composed by crabs followed by fish while velvet belly lanternshark and blackmouth catsharks were composed mainly by shrimps followed by crabs. In addition we found depth-related variations in the dietary habits probably related to natural variations in food availability and morphological effects. There were significant differences in the trophic level between species. At individual level, our results revealed some shifts in individual diets and in some cases individuals from one species had greater similarity in diet with individuals of other species than with individuals of the same species. This study illustrates the importance of using complementary approaches, which will allow more efficient monitoring of food web changes. Furthermore, individual isotopic models open new opportunities for study individual specialization[CAT] Entendre com els depredadors marins estan estructurats i com interactuen és un repte científic. Avui en dia, per estudiar la segregació tròfica, els ecòlegs utilitzen dues metodologies complementàries, el contingut estomacal i l'anàlisi isotòpic. L'objectiu d'aquest estudi va ser examinar l'ecologia tròfica de tres condrictis (Negret, Moixina i Guilla) que són comuns en els descarts del Golf de Lleó (NO Mediterrani). Per a cada espècie, es va analitzar la dieta i les possibles diferències de la dieta entre els sexes, les profunditats i els individus. Hem combinat dues metodologies, l'anàlsi de contingut estomacal (% N i % FO) i l'anàlisi d'isòtops estables per realitzar models bayesians de mescla isotòpica (combinant els valors isotòpics de depredadors i preses). També es van calcular els nivells tròfics de cada espècie. Els nostres resultats van mostrar una clara segregació entre quimeres i les altres dues espècies. La quimera mostrava una dieta composta principalment per crancs i peixos, mentre que la dieta del negret i la moixina estaven formades principalment per gambes i crancs. A més trobem variacions de la dieta relacionats amb la profunditat probablement degut a variacions naturals en la disponibilitat d'aliments i degut a efectes morfològics. No hi va haver diferències significatives del nivell tròfic entre les espècies. A nivell individual, els resultats van revelar alguns canvis en les dietes individuals i en alguns casos els individus d'una espècie presentaven una major similitud en la dieta amb individus d'altres espècies que amb els individus de la mateixa espècie. Aquest estudi il·lustra la importància d'utilitzar mètodes complementaris, la qual cosa permetrà un seguiment més eficaç dels canvis en les xarxes tròfiques. D'altra banda, els models isotòpics individuals obrin noves oportunitats per estudiar la especialització individualPeer Reviewe

Ecological and functional role of small and medium pelagic fish in the northwestern Mediterranean Sea : Rol ecológico y funcional de los peces pelágicos pequeños y medianos en el noroeste del mar Mediterráneo

Mediterranean marine ecosystems are fundamentally driven by their pelagic communities and small and medium-size pelagic fishes (SMPF) play crucial ecological roles. Although fluctuations of the populations of these organisms have been mainly attributed to environmental variability and overfishing, there is still a lack of understanding on specific mechanisms that drive their population changes. In recent decades a decline in landings, biomass and body condition of sardine and anchovy in the Mediterranean Sea has been observed and several hypotheses to explain these changes have been formulated. Therefore, accurate scientific data at species and community level is needed in order to understand the most likely causes of these declines. Within this context, this PhD thesis aims to improve the knowledge of the seasonal dynamics and functioning of the pelagic compartment focusing in the trophic relationships and energy dynamics of SMPF in the northwestern Mediterranean Sea. I used different methods to advance on the knowledge about the ecological and functional role of several pelagic fish species in the western Mediterranean Sea, including clupeoids, horse mackerels and mackerels. Specifically, stable isotope and stomach content analyses in combination with direct and indirect body condition indeces, were used to study seasonal variation in energy content in relation to their breeding strategies, feeding preferences and trophic role in the pelagic food-web. Results showed stability in the trophic structure through the year with a trophic segregation of small pelagic fish depending on the ontogenetic stage. Seasonal differences in energy density were highly related with the spawning season and food availability. To integrate the new findings and to test the role of potential pressures on main pelagic species, I developed qualitative food-web models. Overall, results provide pivotal information to assist the adaptive management of pelagic fish species in the region.Els ecosistemes marins mediterranis estan fonamentalment dirigits per les seves comunitats pelàgiques on els peixos pelàgics petits i mitjans (SMPF) exerceixen funcions ecològiques crucials. Si bé les fluctuacions de les seves poblacions s'han atribuït principalment a la variabilitat ambiental i la sobrepesca, encara hi ha una manca de comprensió sobre els mecanismes específics que impulsen els canvis en la població. En les últimes dècades s'ha observat una disminució en la biomassa, en els desembarcaments i en la condició de la sardina i l'anxova al mar Mediterràni, i s'han formulat diverses hipòtesis per explicar aquests canvis. Actualment, es necessiten dades científiques precises a nivell d'espècies i comunitats per comprendre les causes més probables d'aquestes disminucions. En aquest context, aquesta tesi doctoral pretén millorar el coneixement de la dinàmica estacional i el funcionament del compartiment pelàgic, centrant-se en les relacions tròfiques i la dinàmica energètica dels SMPF al nord-oest del Mar Mediterrani. Diferents tècniques es varen fer servir per avançar en el coneixement del paper ecològic i funcional de diverses espècies de peixos pelàgics al mar Mediterrani occidental, incloent clupèids, sorells i verats. En concret, es varen utilitzar anàlisi d'isòtops estables i de contingut estomacal en combinació amb índexs directes i indirectes de condició corporal, per estudiar la variació estacional del contingut d'energia en relació amb les seves estratègies de reproducció, preferències tròfiques i paper tròfic en la comunitat pelàgica. Els resultats van mostrar estabilitat en l'estructura tròfica al llarg de l'any amb una segregació tròfica dels peixos pelàgics petits en funció de l'etapa ontogenètica. Les diferències estacionals en la densitat energètica van estar altament relacionades amb la temporada de reproducció i la disponibilitat d'aliments. Per integrar tota aquesta informació i testar el paper de les pressions potencials en les principals espècies pelàgiques, es va desenvolupar un model qualitatiu. En general, els resultats proporcionen informació fonamental per contribuir al maneig adaptatiu de les espècies de peixos pelàgics a la regióLos ecosistemas marinos mediterráneos están fundamentalmente condicionados por sus comunidades pelágicas donde los peces pelágicos pequeños y medianos (SMPF) desempeñan funciones ecológicas cruciales. Si bien las fluctuaciones de sus poblaciones se han atribuido principalmente a la variabilidad ambiental y la sobrepesca, todavía hay una falta de comprensión sobre los mecanismos específicos que impulsan los cambios en las poblaciones pelágicas. En las últimas décadas se ha observado una disminución en la biomasa, en los desembarques y en la condición de la sardina y la anchoa del noroeste del mar Mediterráneo, y se han formulado varias hipótesis para explicar estos cambios. Actualmente, se necesitan datos científicos precisos a nivel de especies y comunidades para comprender las causas más probables de estas disminuciones. En este contexto, esta tesis doctoral pretende mejorar el conocimiento de la dinámica estacional y el funcionamiento del compartimento pelágico, centrándose en las relaciones tróficas y la dinámica energética de los SMPF en el noroeste del mar Mediterráneo. Se usaron diferentes técnicas para avanzar en el conocimiento del papel ecológico y funcional de varias especies de peces pelágicos en el Mar Mediterráneo occidental, incluyendo clupeoides, jureles y caballas. En concreto, se utilizó el análisis de isótopos estables y de contenido estomacal en combinación con índices directos e indirectos de condición corporal, para estudiar la variación estacional del contenido de energía en relación con las estrategias de reproducción de los SMPF, las preferencias tróficas y el papel trófico en la comunidad pelágica. Los resultados mostraron estabilidad en la estructura trófica a lo largo del año con una segregación trófica de peces pelágicos pequeños en función del estadío ontogenético. Las diferencias estacionales en la densidad energética estuvieron altamente relacionadas con el periodo de reproducción y la disponibilidad de alimentos. Para integrar toda esta información y testar el rol de las presiones potenciales en las principales especies pelágicas, se desarrolló un modelo cualitativo. Los resultados mostraron que un aumento de la temperatura de la superficie del mar en combinación con el aumento de la explotación de la sardina y la anchoa y cambios en la composición del zooplancton fueron las presiones más plausibles para explicar los cambios observados en las poblaciones de peces pelágicos pequeños. En general, estos resultados proporcionan información fundamental para contribuir al manejo adaptativo de las especies de peces pelágicos en la región

Proyectos de investigación SPELMED y PELWEB : Evaluación del estado de las poblaciones de peces pelágicos pequeños

XI Reunión del Foro Científico sobre la pesca española en el Mediterráneo, septiembre 2018. Alicante.-- 4 pagesEn la última década ha habido un declive en las poblaciones de sardina (Sadina pilchardus) y boquerón (Engraulis encrasicolus) en el noroeste del Mediterráneo tanto a nivel de capturas como de biomasa y también en su estado de condición. El actual declive se ha relacionado con un alto impacto de la pesca o con efectos ecosistémicos como un cambio en la alimentación debido a una peor calidad o cantidad del plancton (Brosset et al., 2017; GFCM, 2016). A pesar de que hay disponible diferentes estudios sobre la biología, ecología y gestión de estas dos especies, esta información está fragmentada y un mayor esfuerzo es necesario para poder integrar toda la información disponible y desarrollar un conocimiento robusto para poder gestionar mejor estas especies. Por ello actualmente en el Instituto de Ciencias del Mar de Barcelona (ICM-CSIC) estamos llevando a cabo dos proyectos muy relacionados entre ellos. El proyecto SPELMED: “Evaluación del estado de las poblaciones y alternativas de gestión específicas para las poblaciones de peces pelágicos pequeños del noroeste del Mediterráneo” (Framework Contract No. EASME/EMFF/2016/032, Specific Contract No. 2, 2018), y el proyecto PELWEB "Ganadores, perdedores y cambios de la red trófica pelágica del Mediterráneo Occidental: de consecuencias ecológicas a proyecciones futuras" (proyecto Estatal de I+D+I RETOS, 2018-2020). Este último proyecto acaba de iniciarse. El proyecto SPELMED abarca las subareas geográficas (GSA) 6 - Norte de España (GSA) 7 – Golfo de León, y se centra en las poblaciones de Sardina pilchardus (sardina) y Engraulis encrasicolus (boquerón), sin olvidar el ecosistema marino y las interacciones con la pesca. SPELMED tiene tres objetivos específicos y cada uno de ellos subdivididos: [...]Peer reviewe

Assessing the trophic ecology and ecological role of small and medium pelagic fish in the Mediterranean Sea; insights from diet studies, isotopic data and food-web models

The 3rd CLIOTOP Symposium,14-18 September 2015, San Sebastian, SpainSmall and Medium Pelagic Fish (SMPF) such as, clupeids, horse mackerels and mackerels, have been described as key species in the functioning of marine ecosystems. Moreover, they support important fisheries worldwide. Accurate knowledge of their feeding ecology and ecological role is necessary in order to develop realistic quantitative assessments and to exploit and manage these species in a sustainable way. In this review, we synthesize all available information concerning the feeding habits, ecological role and potential predators of seven commercially and ecologically important species of SMPF (Engraulis encrasicolus, Sardina pilchardus, Sardinella aurita, Trachurus trachurus, T. mediterraneus, Scomber scombrus, S. colias) in the Mediterranean Sea. Specifically, information gathered from stomach content analyses, stable isotope analyses and ecosystem models (Ecopath) is analyzed to study whether the trophic role and feeding habits vary among Mediterranean regions and ecosystems. We obtain a global view of the importance of these species in different areas of the Mediterranean Sea and identify major information gaps. Several predators are found to prey on SMPF, with important contributions of the species studied to the total diet of apical predators. The results reveal that SMPF are identified as pivotal species of the food web playing important ecological roles such as structuring or keystone species. Medium pelagic fish, mainly Scomber spp. are the less studied species, in special in the south-eastern Mediterranean waters. By highlighting the important gaps in the ecological information of these species this study provides a guide for scientist and managers on research priorities in the Mediterranean SeaPeer Reviewe