Multibiomarker biomonitoring approach using three bivalve species in the Ebro Delta (Catalonia, Spain)

Bivalves have proved to be useful bioindicators for environmental pollution. In the present study, mussels (Mytilus galloprovincialis), cockles (Cerastoderma edule), and razor shells (Solen marginatus) were collected in the Ebro Delta, an extensive area devoted to rice farming and affected by pesticide pollution, from April to July, the heaviest rice field treatment period. Possible effects of pollution were assessed through biochemical markers (carboxylesterase (CE), antioxidant and neurotoxicity-related enzymes, and lipid peroxidation levels). Data on environmental variables, bivalve reproductive condition, and presence of organic pollutants, marine phycotoxins, pathogens, or histopathological conditions in bivalve’s tissues were also evaluated. Although the bioaccumulated pesticides did not explain the patterns observed for biochemical responses, the obtained results point to an effect of environmental pesticide pollution on enzymatic markers, with a prominent contribution of CE to such changes. Mussels and razor shells provided a more sensitive biochemical response to pollution than cockles. Environmental variables, bivalve reproductive condition, and marine phycotoxins did not seem to have a relevant effect on the biomarkers assessed.info:eu-repo/semantics/acceptedVersio

Assessment of the health status of the European anchovy (Engraulis encrasicolus) in the NW Mediterranean Sea from an interdisciplinary approach and implications for food safety

Acord transformatiu CRUE-CSICThe European anchovy (Engraulis encrasicolus) is a small pelagic fish with an outstanding commercial value supporting important fisheries and is a key component of pelagic ecosystems in the Mediterranean Sea. Progressive reductions in the population size of this species has been observed in the Mediterranean Sea during recent decades, accompanied by a decline in the body condition, as well as the size/age of maturation. Nonetheless, the health status has not been yet assessed using a holistic approach. Herein, we analyse the health status of the European anchovy, integrating distinct indicators from fish condition, enzymatic biomarkers, presence of tissue alterations, and parasite descriptors. In addition, we analyse the presence of anthropogenic items (AIs) in the digestive tract of fish and their potential impact on health status. Additionally, we assess the differences between current AIs values and those recorded over 12 years ago. None of the health indicators studied provided evidence of relevant pathologic conditions affecting this fish species in the studied area. However, changes in the pattern of liver parenchyma were found. Compared with anchovy populations from other distribution areas, no zoonotic parasites were recorded in this study, demonstrating a reduced risks associated with foodborne transmission to humans. AIs, such as fibres and plastic particles, were found in the digestive tract of half of the fish analysed. A significant increase was detected in AIs prevalence between 2007 (40 %) and 2019 (70 %), alongside differences in the abundance and typology of the AIs, though this does not seem to have impacted fish health yet. Therefore, our work underscores the importance of implementing a regular program to monitor the health status of this key species to better understand population dynamics and their drivers

Morphological and molecular description of Rhadinorhynchus laterospinosus Amin, Heckmann & Ha, 2011 (Acanthocephala, Rhadinorhynchidae) from marine fish off the Pacific coast of Vietnam

Rhadinorhynchus laterospinosus Amin, Heckmann & Ha, 2011 (Rhadinorhynchidae) was described from a single female collected from a trigger fish, Balistes sp. (Balistidae) from the northern Pacific coast of Vietnam in Halong Bay, Gulf of Tonkin. More recent collections of fishes in 2016 and 2017 revealed wider host and geographical distributions. We report this Acanthocephala from nine species of fish representing six families (including the original record from Balistes sp.) along the whole Pacific coast of Vietnam. The fish species are Alectis ciliaris (Carangidae), Auxis rochei (Scombridae), Auxis thazard (Scombridae), Leiognathus equulus (Leiognathidae), Lutjanus bitaeniatus (Lutjanidae), Megalaspis cordyla (Carangidae), Nuchequula flavaxilla (Leiognathidae), and Tylosurus sp. (Belonidae). We provide a complete description of males and females of R. laterospinosus, discuss its hook metal microanalysis using EDAX, and its micropores. Specimens of this species characteristically have lateral trunk spines bridging the anterior ring of spines with posterior field of ventral spines and a proboscis with 15–19 longitudinal alternating rows of 21–26 hooks each varying with host species. We demonstrate the effect of host species on the distribution and size of the trunk, proboscis, proboscis hooks, trunk spines, and reproductive structures. The molecular profile of this acanthocephalan, based on 18S rDNA and cox1 genes, groups with other Rhadinorhynchus species and further seems to confirm the paraphyly of the genus, which is discussed

Twenty thousand parasites under the sea : a multidisciplinary approach to parasite communities of deep-dwelling fishes from the slopes of the Balearic Sea (NW Mediterranean) /

BibliografiaPremi Extraordinari de Doctorat concedit pels programes de doctorat de la UAB per curs acadèmic 2016-2017El Mar Mediterráneo profundo permanece en gran parte inexplorado, y, específicamente, las comunidades parásitas de los peces mediterráneos de aguas profundas son mayormente desconocidas. El principal objetivo de la presente tesis es caracterizar las comunidades parásitas de las importantes especies ícticas de aguas profundas siguientes: Mora moro (Risso, 1810), Phycis blennoides (Brünnich, 1768), Galeus melastomus Rafinesque, 1810, Scyliorhinus canicula (Linnaeus, 1758), Etmopterus spinax (Linnaeus, 1758) y Centroscymnus coelolepis Barbosa du Bocage and de Brito Capello, 1864. Otro propósito importante es evaluar la respuesta de estas comunidades a gradientes y variables ambientales, a la dieta y a la ecología trófica de los hospedadores y su posible impacto en el estado de salud de estos últimos. En los capítulos tercero a sexto se describen las comunidades parásitas de las especies mencionadas en diferentes estaciones, estratos de profundidad y localidades de las vertientes continental e insular del Mar Balear. Mientras que las comunidades parásitas de M. moro, P. blennoides y G. melastomus se caracterizaron por altos valores abundancia, riqueza y diversidad, las de S. canicula, E. spinax y C. coelolepis eran comparativamente más pobres y menos diversas. Diferencias ontogénicas, batimétricas, estacionales y geográficas se detectaron en las comunidades parásitas de las especies tratadas, en todos los casos asociadas a las dinámicas alimentarias (a su vez asociadas a la disponibilidad de presas a lo largo de los gradientes mencionados, en la mayoría de casos) de sus hospedadores. Se hallaron relaciones detalladas entre parásitos y presas ingeridas por los diferentes hospedadores, permitiendo confirmar las vías de transmisión ya conocidas para algunos parásitos y sugiriendo nuevas vías de infección para otros. La mayoría de parásitos se asociaron a altos niveles de O2 y turbidez del agua. Mientras que los primeros favorecen la abundancia de parásitos con ciclos indirectos como resultado de la proliferación del zooplancton y la agregación de hospedadores intermediarios potenciales asociada, los segundos favorecen la transmisión de parásitos y aumentan la carga parasitaria debido a un incremento del zooplancton y de las comunidades de invertebrados suprabentónicos a causa de una mayor disponibilidad de nutrientes. Altos niveles de salinidad del agua parecieron estar asociados a mayores abundancias de los nematodos Hysterothylacium aduncum y Proleptus obtusus, probablemente porque la salinidad se correlaciona con la abundancia de decápodos y misidáceos, entre otros, que son utilizados por esos nematodos como hospedadores intermediarios. A su vez, altos niveles de temperatura del agua se asociaron a la abundancia de parásitos monogeneos, probablemente debido a un mayor éxito de eclosión de los huevos y a una reducción del tiempo de maduración reproductiva a mayores temperaturas, como ya había sido demostrado para estos parásitos. Se detectaron una inhibición de la enzima acetilcolinesterasa y mayores niveles de peroxidación de lípidos, ambos posiblemente asociados a estrés por las infecciones parasitarias, en varias especies de peces. En general, la carga parasitaria no tuvo un impacto significativo en los índices de condición generales de los peces, ni en el número y/o área de centros macrofágicos o melanomacrofágicos esplénicos en el caso de teleósteos, o en el número de melanomacrófagos hepáticos en el caso de G. melastomus. En el séptimo capítulo se aportan datos morfológicos, moleculares y ecológicos de diferentes estadíos de desarrollo del cestodo Ditrachybothridium macrocephalum en su hospedador definitivo, G. melastomus, y en el Mar Mediterráneo por primera vez. En el octavo capítulo la familia de cestodos Sphyriocephalidae es revisada. Se describe la nueva especie Heterosphyriocephalus encarnae n. sp., y dos especies ya existentes, Sphyriocephalus viridis y Sphyriocephalus tergestinus, se redescriben a partir de datos morfológicos y moleculares de nuevo material recolectado y de material de museo.The Mediterranean deep-sea remains mostly unexplored and, specifically, the parasite communities of Mediterranean deep-dwelling fishes are largely unknown. The central purpose of the present thesis is to characterize the parasite communities infecting the following important deep-dwelling ichthyc species in the Balearic Sea: Mora moro (Risso, 1810), Phycis blennoides (Brünnich, 1768), Galeus melastomus Rafinesque, 1810, Scyliorhinus canicula (Linnaeus, 1758), Etmopterus spinax (Linnaeus, 1758) and Centroscymnus coelolepis Barbosa du Bocage and de Brito Capello, 1864. Another main objective is to assess the responsiveness of these parasite communities to environmental gradients and variables, to host diet and trophic ecology and their possible impact on host health condition. In the third to sixth chapters, the parasite communities of the mentioned species are described on different seasons, depth strata and localities from the mainland and insular slopes of the Balearic Sea. While parasite communities of M. moro, P. blennoides and G. melastomus were characterized by high abundance, richness and diversity values, those of S. canicula, E. spinax and C. coelolepis were comparatively poorer and less diverse. Ontogenic, bathymetric, seasonal and geographic differences in the parasite communities of the different species addressed were detected, in all cases linked to the feeding dynamics (in turn linked to prey availability across the mentioned gradients, in most cases) of their hosts. Detailed relationships were found between parasite taxa and prey ingested by the different hosts, allowing confirmation of the transmission pathways known for some parasites and suggesting new ways of infection in others. Most parasites were linked to high O2 and turbidity levels. While the former enhances the abundance of parasites with indirect life cycles as a result of zooplankton proliferation and the associated aggregation of potential intermediate hosts, the latter favours parasite transmission and increases parasite loads due to an increase of zooplankton and suprabenthic invertebrate communities linked to higher nutrient availability. High water salinity levels seemed to be linked to higher abundance of the nematodes Hysterothylacium aduncum and Proleptus obtusus, probably because salinity correlates with the abundance of decapods and mysids, among others, which are used by these nematodes as intermediate hosts. In turn, high water temperature levels correlated with the abundance of monogenean parasites, likely due to enhanced egg hatching success and reduced time to maturity, as previously reported for these parasites. An inhibition of acetylcholinesterase activity and increased lipid peroxidation levels were detected in different fish species, possibly associated to infection-related stress. In general, parasite burden did not have a significant effect on fish general condition indices or on the number and/or surface of splenic melano-macrophage or macrophage centres in the case of teleosts, or on the number of hepatic melano-macrophages in the case of G. melastomus. In the seventh chapter, morphological, molecular and ecological data of different developmental stages of the cestode Ditrachybothridium macrocephalum are provided for the first time from its definitive host, G. melastomus, in the Mediterranean Sea. In the eighth chapter, the cestode family Sphyriocephalidae is revised. The new species Heterosphyriocephalus encarnae n. sp. is described, and two already existing species, Sphyriocephalus viridis and Sphyriocephalus tergestinus are further redescribed based on morphological and molecular data of newly-collected and museum material

Twenty thousand parasites under the sea: a multidisciplinary approach to parasite communities of deep-dwelling fishes from the slopes of the Balearic Sea (NW Mediterranean)

Memoria de tesis doctoral presentada por Sara Maria Dallarés Villar para optar al grado de Doctora en Acuicultura por la Universitat Autònoma de Barcelona (UAB), realizada bajo la dirección de la Dra. Maite Carrassón López de Letona de la Universitat Autònoma de Barcelona (UAB), del Dr. Francesc Padrós Bover de la Universitat Autònoma de Barcelona (UAB) y de la Dra. Montserrat Solé Rovira del Institut de Ciències del Mar (ICM-CSIC).-- 208 pages[EN] The Mediterranean deep-sea remains mostly unexplored and, specifically, the parasite communities of Mediterranean deep-dwelling fishes are largely unknown. Parasites are known to be effective bioindicators. Because many of them are trophically-transmitted and show complex life cycles involving more than one host, parasites can reflect host feeding habits, trophic interactions and species composition of their ecosystems. Parasites can also reveal environmental changes of anthropogenic or natural origin, and respond to environmental conditions that may influence their own biology or their hosts’ population dynamics. Furthermore, the differentiation of parasite communities across geographical gradients allows their use as discrimination tags of host populations. [...][ES] El Mar Mediterráneo profundo permanece en gran parte inexplorado, y, específicamente, las comunidades parásitas de los peces mediterráneos de aguas profundas son mayormente desconocidas. Es sabido que los parásitos son efectivos bioindicadores. Debido a que muchos de ellos se transmiten por vía trófica y tienen complejos ciclos vitales que involucran a más de un hospedador, los parásitos pueden reflejar los hábitos alimentarios de sus hospedadores, interacciones tróficas y la composición de especies de sus ecosistemas. Los parásitos pueden también poner de manifiesto cambios ambientales de origen antropogénico o natural, y responder a condiciones ambientales que influyan en su propia biología o en las dinámicas poblacionales de sus hospedadores. Asimismo, la diferenciación de las comunidades de parásitos a lo largo de gradientes geográficos posibilita su uso como marcadores de discriminación de las poblaciones de hospedadores. [...]Peer Reviewe

Relació entre els paràsits, la dieta i l'estat de salut d'un peix del Mediterrani profund

El Mediterrani profund és un ecosistema molt vulnerable del que tenim un coneixement encara força incomplet. Recentment s'ha realitzat un estudi centrat en els paràsits que infecten les poblacions de mora comú (Mora moro) de la costa de Barcelona i de les Illes Balears que viuen a una fondària d'entre 1.000 i 1.400 m. Els resultats mostren una comunitat paràsita molt abundant i diversa que respon a les variables ambientals i que podria permetre la diferenciació de les poblacions d'ambdues vessants, així com una major presència i diversitat de paràsits en els peixos més sans

Twenty thousand parasites under the sea: a multidisciplinary approach to parasite communities of deep-dwelling fishes from the slopes of the Balearic Sea (NW Mediterranean)

El Mar Mediterráneo profundo permanece en gran parte inexplorado, y, específicamente, las comunidades parásitas de los peces mediterráneos de aguas profundas son mayormente desconocidas. El principal objetivo de la presente tesis es caracterizar las comunidades parásitas de las importantes especies ícticas de aguas profundas siguientes: Mora moro (Risso, 1810), Phycis blennoides (Brünnich, 1768), Galeus melastomus Rafinesque, 1810, Scyliorhinus canicula (Linnaeus, 1758), Etmopterus spinax (Linnaeus, 1758) y Centroscymnus coelolepis Barbosa du Bocage and de Brito Capello, 1864. Otro propósito importante es evaluar la respuesta de estas comunidades a gradientes y variables ambientales, a la dieta y a la ecología trófica de los hospedadores y su posible impacto en el estado de salud de estos últimos. En los capítulos tercero a sexto se describen las comunidades parásitas de las especies mencionadas en diferentes estaciones, estratos de profundidad y localidades de las vertientes continental e insular del Mar Balear. Mientras que las comunidades parásitas de M. moro, P. blennoides y G. melastomus se caracterizaron por altos valores abundancia, riqueza y diversidad, las de S. canicula, E. spinax y C. coelolepis eran comparativamente más pobres y menos diversas. Diferencias ontogénicas, batimétricas, estacionales y geográficas se detectaron en las comunidades parásitas de las especies tratadas, en todos los casos asociadas a las dinámicas alimentarias (a su vez asociadas a la disponibilidad de presas a lo largo de los gradientes mencionados, en la mayoría de casos) de sus hospedadores. Se hallaron relaciones detalladas entre parásitos y presas ingeridas por los diferentes hospedadores, permitiendo confirmar las vías de transmisión ya conocidas para algunos parásitos y sugiriendo nuevas vías de infección para otros. La mayoría de parásitos se asociaron a altos niveles de O2 y turbidez del agua. Mientras que los primeros favorecen la abundancia de parásitos con ciclos indirectos como resultado de la proliferación del zooplancton y la agregación de hospedadores intermediarios potenciales asociada, los segundos favorecen la transmisión de parásitos y aumentan la carga parasitaria debido a un incremento del zooplancton y de las comunidades de invertebrados suprabentónicos a causa de una mayor disponibilidad de nutrientes. Altos niveles de salinidad del agua parecieron estar asociados a mayores abundancias de los nematodos Hysterothylacium aduncum y Proleptus obtusus, probablemente porque la salinidad se correlaciona con la abundancia de decápodos y misidáceos, entre otros, que son utilizados por esos nematodos como hospedadores intermediarios. A su vez, altos niveles de temperatura del agua se asociaron a la abundancia de parásitos monogeneos, probablemente debido a un mayor éxito de eclosión de los huevos y a una reducción del tiempo de maduración reproductiva a mayores temperaturas, como ya había sido demostrado para estos parásitos. Se detectaron una inhibición de la enzima acetilcolinesterasa y mayores niveles de peroxidación de lípidos, ambos posiblemente asociados a estrés por las infecciones parasitarias, en varias especies de peces. En general, la carga parasitaria no tuvo un impacto significativo en los índices de condición generales de los peces, ni en el número y/o área de centros macrofágicos o melanomacrofágicos esplénicos en el caso de teleósteos, o en el número de melanomacrófagos hepáticos en el caso de G. melastomus. En el séptimo capítulo se aportan datos morfológicos, moleculares y ecológicos de diferentes estadíos de desarrollo del cestodo Ditrachybothridium macrocephalum en su hospedador definitivo, G. melastomus, y en el Mar Mediterráneo por primera vez. En el octavo capítulo la familia de cestodos Sphyriocephalidae es revisada. Se describe la nueva especie Heterosphyriocephalus encarnae n. sp., y dos especies ya existentes, Sphyriocephalus viridis y Sphyriocephalus tergestinus, se redescriben a partir de datos morfológicos y moleculares de nuevo material recolectado y de material de museo.The Mediterranean deep-sea remains mostly unexplored and, specifically, the parasite communities of Mediterranean deep-dwelling fishes are largely unknown. The central purpose of the present thesis is to characterize the parasite communities infecting the following important deep-dwelling ichthyc species in the Balearic Sea: Mora moro (Risso, 1810), Phycis blennoides (Brünnich, 1768), Galeus melastomus Rafinesque, 1810, Scyliorhinus canicula (Linnaeus, 1758), Etmopterus spinax (Linnaeus, 1758) and Centroscymnus coelolepis Barbosa du Bocage and de Brito Capello, 1864. Another main objective is to assess the responsiveness of these parasite communities to environmental gradients and variables, to host diet and trophic ecology and their possible impact on host health condition. In the third to sixth chapters, the parasite communities of the mentioned species are described on different seasons, depth strata and localities from the mainland and insular slopes of the Balearic Sea. While parasite communities of M. moro, P. blennoides and G. melastomus were characterized by high abundance, richness and diversity values, those of S. canicula, E. spinax and C. coelolepis were comparatively poorer and less diverse. Ontogenic, bathymetric, seasonal and geographic differences in the parasite communities of the different species addressed were detected, in all cases linked to the feeding dynamics (in turn linked to prey availability across the mentioned gradients, in most cases) of their hosts. Detailed relationships were found between parasite taxa and prey ingested by the different hosts, allowing confirmation of the transmission pathways known for some parasites and suggesting new ways of infection in others. Most parasites were linked to high O2 and turbidity levels. While the former enhances the abundance of parasites with indirect life cycles as a result of zooplankton proliferation and the associated aggregation of potential intermediate hosts, the latter favours parasite transmission and increases parasite loads due to an increase of zooplankton and suprabenthic invertebrate communities linked to higher nutrient availability. High water salinity levels seemed to be linked to higher abundance of the nematodes Hysterothylacium aduncum and Proleptus obtusus, probably because salinity correlates with the abundance of decapods and mysids, among others, which are used by these nematodes as intermediate hosts. In turn, high water temperature levels correlated with the abundance of monogenean parasites, likely due to enhanced egg hatching success and reduced time to maturity, as previously reported for these parasites. An inhibition of acetylcholinesterase activity and increased lipid peroxidation levels were detected in different fish species, possibly associated to infection-related stress. In general, parasite burden did not have a significant effect on fish general condition indices or on the number and/or surface of splenic melano-macrophage or macrophage centres in the case of teleosts, or on the number of hepatic melano-macrophages in the case of G. melastomus. In the seventh chapter, morphological, molecular and ecological data of different developmental stages of the cestode Ditrachybothridium macrocephalum are provided for the first time from its definitive host, G. melastomus, in the Mediterranean Sea. In the eighth chapter, the cestode family Sphyriocephalidae is revised. The new species Heterosphyriocephalus encarnae n. sp. is described, and two already existing species, Sphyriocephalus viridis and Sphyriocephalus tergestinus are further redescribed based on morphological and molecular data of newly-collected and museum material

Life strategies and habitat preferences of Bythitidae and Zoarcidae, specialized fishes with particular life histories, in the Mediterranean deep sea

16 pages, 9 figures, 4 tables, supplementary data https://doi.org/10.1016/j.dsr.2021.103593Deep-sea habitats are home for a variety of yet poorly known fish species, some of which display specialized life strategies, as is the case of Bythitidae and Zoarcidae. With the purpose of elucidating biological and ecological aspects of representatives of these families in NW Mediterranean waters, a large dataset based on 599 specimens of Cataetyx alleni, 30 C. laticeps and 284 Melanostigma atlanticum captured during the last 30 years within the framework of different research projects was used to address their geographical and bathymetric distribution, population structure, reproduction, trophic ecology, parasitism and enzymatic markers in the Balearic basin. Present outcomes revealed a patchy distribution mostly for M. atlanticum, possibly related to aggregation during reproduction and to the association with specific sediments. For the three species, higher densities occurred in the mainland vs. the insular margin, and a diminishing trend in estimated densities over the last decades was observed for C. alleni and M. atlanticum likely linked to climatic oscillations. Trophic data indicated that the two Cataetyx species inhabit the water-sediment interface and mainly feed on suprabenthic prey, while M. atlanticum inhabits the water column near the bottom preying on pelagic organisms and moving towards the seabed during reproduction. These results were supported by the parasitological assessment, which revealed that parasite communities were moderately diverse and abundant for Cataetyx spp. while being highly depauperate for M. atlanticum. Present outcomes from the Mediterranean Sea confirmed reproduction of C. alleni during autumn-winter and of M. atlanticum during autumn. Spawning of the former species may occur in winter-spring, as suggested by the finding, by the first time, of two females captured in March with fully-developed embryos inside. Levels of enzymatic markers quantified in muscle were provided for C. alleni and M. atlanticum for the first time. The special interactions found between the distribution and biology of Bythitidae and Zoarcidae and the sedimentary bottoms that they inhabit indicates that such conventional habitats are more heterogeneous than it is generally assumed and deserve higher attention for future protectionThis work was supported by the Spanish National Research Council (CSIC) and the Spanish Scientific and Technic Research Assessing Commission (CAICYT) projects BATIMAR (grant number PAC 86–008/ID 821) and RETRO (grant number MAR90/757), and by the Spanish Ministry of Science and Innovation (MICYT) projects BIOMARE (grant number CTM2006-13508-C02-01/MAR), ANTROMARE (grant numbers CTM2009–12214–C02–01/MAR and CTM2009–12214–C02–02/MAR) and RECOMARES (gran number RTI2018-094066-B-100)Peer reviewe

Life strategies and habitat preferences of two especialized fish species in the NW Mediterranean deep sea

VII International Symposium on Marine Sciences (ISMS 2020), 1-3 July 2020 (Barcelona).-- 2 pagesCataetyx alleni and Melanostigma atlanticum are two poorly known small-sized fishes showing peculiar features regarding their reproductive biology and behaviour (Silverberg et al., 1987; Follesa et al., 2011). Present research reveals different aspects regarding the biology and ecology of these species in the slopes of the Balearic basin. Specimens were collected during the last 30 years during different oceanographic cruises. Geographical/habitat distribution, population structure, diet, parasite infections and trends on biological indices were addressed. Higher population density of C. alleni was found in the mainland than in the insular slope of the Balearic basin and in the middle (ca. 800-1400 m depth) than in upper and lower slopes (ca. 200-800 and below 1400 m depth, respectively). M. atlanticum was only sampled in the mainland slope, mostly from upper and middle slopes and preferably south to submarine canyons, probably linked to sediment depocenters. For C. alleni, a bigger-deeper trend occurred for both sexes from spring to autumn. For M. atlanticum, this same pattern was observed for females and no seasonal trends were appreciated. Regarding diet, C. alleni intestinal fullness was highest in the upper slope in spring and in the middle slope in summer, and main diet items recovered comprised polynoid polychaetes, calanoid copepods, amphipods, isopods, mysids and decapods. M. atlanticum stomach fullness trends could only be observed in the upper slope, where it was higher in summer than in autumn, and main diet items recovered were calanoid copepods and polychaetes. Parasite assemblages of both species displayed low richness, diversity and abundance, and were largely composed by larval parasites, indicating a low-intermediate position within local food webs. Fo rC. alleni, gonadosomatic index peakedin autumn, coinciding with the reproductive season of this species, and condition factor increased in spring-summer and decreased with depth. Hepatosomatic index increasedin summer for both speciesThis study was supported by the CSIC and CAICYT project BATIMAR and by the MICYT projects BIOMARE, ANTROMARE and RECOMARESPeer reviewe