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Troballes recents de les espècies de peixos d'aigües profundes Tetragonurus cuvieri Risso, 1810 i Notacanthus bonaparte Risso, 1840 (Chordata, Teleostei) al sud–oest d'Europa (golf de Cadis, SO d'Espanya) Dos exemplars dels peixos d'aigües profundes Tetragonurus cuvieri Risso, 1810 i Notacanthus bonaparte Risso, 1840 van ser capturats al golf de Cadis al gener de 2023 a una profunditat de 14,15 m i al març de 2023 a una profunditat de 532 m, respectivament. La identitat dels exemplars es va verificar mitjançant criteris morfològics i genètics. En aquest estudi recopilem informació sobre les aparicions d'aquestes dues espècies d'aigües profundes a tot el món, l'observació de les quals és infreqüent en aigües poc profundes de la península Ibèrica. Posem en relleu la importància de portar a terme més recerques per conèixer tota la gamma d'espècies que habiten aquestes aigües poc profundes, perquè la seva presència pot proporcionar informació sobre les condicions ambientals i els hàbitats específics existents al golf de Cadis atès que aquests peixos s’associen sovint a rangs de profunditat i característiques oceanogràfiques particulars.

This study provides a comprehensive analysis of the eco-physiological responses of the blue crab (Callinectes sapidus) to variations in salinity, shedding light on its adaptability and invasive success in aquatic environments. Gender-specific differences in osmoregulation and Electron Transport System (ETS) activity highlight the importance of considering sex-specific aspects when understanding the physiological responses of invasive species. Females exhibited increased ETS activity at lower salinities, potentially indicative of metabolic stress, while males displayed constant ETS activity across a range of salinities. Osmoregulatory capacity which depended on gender and salinity, was efficient within meso-polyhaline waters but decreased at higher salinities, particularly in males. These findings provide valuable understandings into how C. sapidus specimens in an invaded area responds to salinity changes, important for considerate its distribution through saline pathways during tidal cycle fluctuations. This study shows the importance of interdisciplinary research for effective management of invasive species and conservation of affected aquatic ecosystems., Competing Interests: Declaration of competing interest The authors declare that they have no known conflicts of interest or personal relationships that could have influenced the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Marine species raft on floating litter, including various plastics, potentially spreading non-native species and threatening global marine habitats. Despite limited attention, Didemnum vexillum, an invasive colonial tunicate in Europe, colonised coasts of southwest Scotland (2009) and northeast Ireland (2012), likely transported via rafting. We studied D. vexillum survival and performance on three plastic types (Polyethylene, Polypropylene and Polystyrene) finding high survival rates over 42 days, with colonies thriving best on PS. Using these data, hydrodynamic and particle tracking models simulated dispersal from existing Irish Sea colonies, projecting potential rafting distances of up to ∼150 km for surface particles influenced by tide and wind, and half that for neutrally-buoyant mid-depth particles driven by tidal currents alone. Hence, the modelling supports the potential for dispersion of this species within the Irish Sea via rafting. This study highlights marine plastics as a vector that may facilitate widespread dispersal of non-native species., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The Atlantic croaker Micropogoniasundulatus , a sciaenid fish native to the North Atlantic American coast, holds importance in recreational and commercial fisheries. Moreover, its potential as an invasive species should be noted, given its expansion and establishment in Atlantic European waters. This study reports its southernmost occurrence in Europe, in the Gulf of Cadiz. Morphological and molecular analysis confirmed its identity, revealing genetic similarities to US sequences. A comprehensive review of historical non-native distribution records underscored the species' expansion throughout European waters, suggesting human-mediated introduction. The escalating frequency of such arrivals emphasises the critical need for effective monitoring and management efforts in order to control non-native species in this region., Competing Interests: No conflict of interest to declare Disclaimer: This article is (co-)authored by any of the Editors-in-Chief, Managing Editors or their deputies in this journal., (Gustavo Freire de Carvalho-Souza, Cristóbal Lobato Gómez, Enrique González-Ortegón.)

In order to study the trophic level of small tuna species and their contribution to the carbon flow in pelagic food webs, an analysis of carbon and nitrogen stable isotopes was carried out. The investigation was focused on four small tuna species ( Auxis rochei , Auxis thazard , Euthynnus alletteratus and Sarda sarda ) commonly harvested in the northeast Atlantic Ocean. The isotope analysis showed how the results for S. sarda are different from the rest of the species analysed, with a higher trophic level, similar to other major tuna species. The greatest niche overlap in δ 13 C and δ 15 N occurs among A. rochei , A. thazard and E. alletteratus . Auxis rochei and E. alletteratus showed a size-dependent variability in δ 15 N, and in δ 13 C for S. sarda . The small tuna S. sarda exhibits the highest migration rates among various geographical areas in comparison to other small pelagic tunas, and the seasonal variability of isotope values in the area studied can be attributed to the incorporation of larger individuals with a higher lipid content. The results of this work provide new information on the ecological role played by small tuna in food webs, which is more complex and varied than currently thought. This knowledge is essential for a more effective management of fisheries.

Concerning microplastics (MPs) contamination is increasing due their negative impacts on marine food webs and their potential toxicity to wildlife and humans. In this study, we analyze the presence of MPs in the stomachs of the commercial fish species Scomber colias (Atlantic chub mackerel) in the Gulf of Cadiz (GoC). Out of the 104 analyzed stomachs, 90.4 % contained some type of MPs, with an average of 5.4 MPs per individual. Of the 1152 MPs analyzed, 91.1 % were fibers, and 8.9 % fragments type. Fourier Transformation Infrared Spectrometry analysis was performed on 152 items, revealing that 73.6 % were MPs. The most common synthetic polymers found were polyamide (64 %), polypropylene (15 %), polystyrene (12 %), polyvinyl chloride (5 %), and polyethylene (4 %). The consistent ingestion of synthetic polymers by the individuals of Atlantic chub mackerel across different zones might suggest an even distribution of MP contamination throughout the GoC., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Changes in the temperature or salinity of ocean waters can affect marine organisms at multiple trophic levels. Both environmental variables could have an impact on marine microalgae populations. Therefore, the effect of the combination of three levels of temperature (20, 24 and 28 °C), and three levels of salinity (33, 36, and 39 PSU) were evaluated on the growth of a multispecies community of five common species of phytoplankton: (one cyanobacteria, Synechococcus sp., and four microalgae, Chaetoceros gracilis, Amphidinium carterae, Pleurochrysis roscoffensis and Rhodomonas baltica). The co-culture was monitored by flow cytometry under controlled conditions in a 96 h study. The effect of both variables on dissolved oxygen concentrations was measured using the SDR SensorDish Reader system. The results demonstrated that Synechococcus sp., C. gracilis, and A. carterae displayed a high growth at the temperature of 28 °C combined with the lowest salinity assayed. However, salinity increases negatively affected the growth of P. roscoffensis and R. baltica. Decreased salinity combined with decreased temperature exhibited a higher net O 2 production. The interaction of two environmental factors related to global change such as temperature and salinity can cause structural (community growth) and functional (net oxygen production) changes in a phytoplanktonic community., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)