This paper reports the first record of a rare deep-sea fish Ijimaia loppei Roule, 1922 (Ateleopodiformes: Ateleopodidae) in the Southwest Iberian Peninsula, based on a single specimen (total length 1271 mm) bottom trawled in the mud volcano field in the Gulf of Cadiz, Spain (36º 28′ 54'' N, 7º 07′ 47'' W), at a depth of 585 m, on April 24, 2024. The morphometric and meristic measurements of I. loppei and its congener, I. antillarum, are presented and compared to previously published data. Further, this study provides insights into the diet of I. loppei and fills a gap in the known geographical distribution of the species, thereby contributing to the understanding of the ichthyofaunal biodiversity in the Gulf of Cadiz and establishing conservation strategies for habitats of ecological importance, such as the mud volcanoes.

The ever-accelerating process of introduction and establishment of invasive alien species (IAS) in marine waters
requires engaging different actors in the management and planning. To address this challenge, stakeholders need
an integrated approach for defining actions of control and management within an ecosystem-based framework:
to seek and enhance coordination, collaboration and trust among all stakeholders affected by changes in linked
marine social - ecological systems. This study explores the complexities and opportunities in managing
economically valuable IAS, demonstrating the need for tailored management strategies that consider key
ecological details needed for successful control such as timing of removals and key economic considerations such
as appropriate incentive mechanisms and time horizons in favor of long-term conservation goals. We propose a
set of actions that can serve as a roadmap for effective IAS control and management, considering their dual role
as nuisances and valuable resources. These actions pertain to local, regional and international levels, encouraging meaningful stakeholder engagement through co-management structures that can foster the development of
robust management plans, enabling better IAS control. The outcome holds potential for positive contributions to
the blue economy— sustainable use of marine resources, including fisheries, tourism, and renewable energy—
and for meeting sustainability objectives.

Life history parameters are indicators of stock structure and the dynamics of populations. In this work, we examine multiple life-history parameters (size distribution, growth, mortality, and longevity) of Palaemon longirostris H. Milne Edwards, 1837 inhabiting the estuarine temperate waters of the Guadalquivir estuary through size-frequency distribution data obtained from June 1997 to May 1999. Sexual dimorphism in size was evident, as females displayed a larger body size with a maximum size of 19.1 mm CL compared to males’ 11.7 mm. The carapace length–weight relationship indicated an allometric growth pattern in both sexes. Additionally, the growth performance index was 2.50 for females compared to 2.33 for males. The recruitment pattern analysis of P. longirostris indicated that females experienced a recruitment rate distributed throughout the warm period between March and August, while males exhibited a higher concentration of recruitment from late spring to early summer. Our study found that natural and fishing mortality rates were similar among male P. longirostris, whereas fishing mortality had a smaller effect on the overall mortality of females. The exploitation rates for both male and female stocks were optimally balanced.

© 2024 Gustavo de Carvalho-Souza, Cristóbal Gómez, Enrique González-Ortegón. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited., The Atlantic croaker Micropogonias undulatus, 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., GF de C-S acknowledges support from the Spanish Ministry of Universities for the Margarita Salas Postdoctoral Fellowship funded through the Next Generation EU programme (UCA/R155REC/2021) and Spanish State Research Agency (PTA2022-021378-I)., Peer reviewed

This paper reports the first record of a rare deep-sea fish Ijimaia loppei Roule, 1922 (Ateleopodiformes: Ateleopodidae) in the Southwest Iberian Peninsula, based on a single specimen (total length 1271 mm) bottom trawled in the mud volcano field in the Gulf of Cadiz, Spain (36º 28′ 54'' N, 7º 07′ 47'' W), at a depth of 585 m, on April 24, 2024. The morphometric and meristic measurements of I. loppei and its congener, I. antillarum, are presented and compared to previously published data. Further, this study provides insights into the diet of I. loppei and fills a gap in the known geographical distribution of the species, thereby contributing to the understanding of the ichthyofaunal biodiversity in the Gulf of Cadiz and establishing conservation strategies for habitats of ecological importance, such as the mud volcanoes., Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. Agencia Estatal de Investigación, PTA2022-021378-I, FPU-UCA predoctoral contract, UCA/REC65VPCT/2022., Peer reviewed

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., This work was funded by the Spanish Ministerio de Ciencia e Innovación through InvBlue project number PID2019-105978RA-I00., GF de C–S acknowledges the support received from the Spanish State Research Agency (PTA2022-021378-I). IH was supported by a competitive postdoctoral contract granted by Universidad de Las Palmas de Gran Canaria (PIC ULPGC-2020)., Peer reviewed

Life history parameters are indicators of stock structure and the dynamics of populations. In this work, we examine multiple life-history parameters (size distribution, growth, mortality, and longevity) of Palaemon longirostris H. Milne Edwards, 1837 inhabiting the estuarine temperate waters of the Guadalquivir estuary through size-frequency distribution data obtained from June 1997 to May 1999. Sexual dimorphism in size was evident, as females displayed a larger body size with a maximum size of 19.1 mm CL compared to males’ 11.7 mm. The carapace length–weight relationship indicated an allometric growth pattern in both sexes. Additionally, the growth performance index was 2.50 for females compared to 2.33 for males. The recruitment pattern analysis of P. longirostris indicated that females experienced a recruitment rate distributed throughout the warm period between March and August, while males exhibited a higher concentration of recruitment from late spring to early summer. Our study found that natural and fishing mortality rates were similar among male P. longirostris, whereas fishing mortality had a smaller effect on the overall mortality of females. The exploitation rates for both male and female stocks were optimally balanced., GF de C-S thanks the Universidad de Cádiz for postdoctoral support with the Margarita Salas fellowship, funded by the European Union, NextGenerationEU (UCA/R155REC/2021) and the Spanish State Research Agency (PTA2022-021378-I). The authors wish to thank Manuel Ruiz Sánchez for sampling assistance. The study was supported by the Environmental Agency of Autonomous Andalusian Government (Consejería de Medio Ambiente; Junta de Andalucía and MCYT project REN2000–0822 MAR)., Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. Margarita Salas fellowship,UCA/R155REC/2021,Gustavo Freire de Carvalho-Souza,Agencia Estatal de Investigación,PTA2022-021378-I,Gustavo Freire de Carvalho-Souza., Peer reviewed

‘Tropicalization’, the phenomenon of species shifting their ranges, has become increasingly prevalent as a response to environmental modifications induced by global change. This study points to an accelerated tropicalization process of marine fish species in the Gulf of Cadiz, a bioinvasion hotspot adjacent to the Strait of Gibraltar. We report accelerated, unusual, and rare occurrences of 15 fish species expanding and potentially establishing their ranges in the Gulf of Cadiz, driven by ocean warming over the past decade. These new insights are the combined consequence of a range expansion of some species, likely facilitated by temperature increases, an intensification of maritime traffic (with a consequent rise in propagule pressure), and a possible increase in sampling efforts and citizen science., G.F.d.C.-S. acknowledges the support received from the Spanish State Research Agency (PTA2022-021378-I) and the postdoctoral fellowship from the Junta de Andalucía (DGP_POST_2024_00956). Financial support was given by CSIC through Intramural Research program under grant number 2024ICT027., Peer reviewed

[Data availability]
Data are provided within the manuscript (Suppl. material 1) or deposited in the Zenodo Data Repository (Suppl. material 2) at https://doi.org/10.5281/zenodo.16748814, Non-native species are of global conservation concern. Spain is also facing the same challenge, especially due to increasing marine traffic, global trade, and ocean warming. Herein, we report Macrobrachium cf. nipponense from a local fisherman through a citizen science initiative. This is the first record of any species of the genus Macrobrachium in the Iberian Peninsula and the westernmost record of this genus in the European waters. In October 2024, an individual was fished at the mouth of the Guadalquivir River. Accidental transport via ballast water is a likely vector for its introduction into the Guadalquivir River estuary, potentially facilitated by increased maritime traffic from the Danube River Basin as a result of the ongoing war between Russia and Ukraine. Our findings highlight the importance of early detection and continuous ecological monitoring, particularly approaches that incorporate citizen science, as effective tools for tracking non-native species. Engaging local stakeholders, such as fishers, can enhance detection capacity and contribute valuable data to inform for future management strategies aimed at preventing the establishment and spread of non-native and invasive species in the Guadalquivir River and other vulnerable aquatic systems., GF de C-S acknowledges support from the Spanish State Research Agency (PTA2022-021378-I) and the postdoctoral fellowship from the Junta de Andalucía (DGP_POST_2024_00956)., Peer reviewed

This dataset compiles records of Macrobrachium nipponense occurrences across its non-native range, including geographical and bibliographical information. It supports the article “A new non-native species detected through citizen science: the presence of a Macrobrachium species (Decapoda, Palaemonidae) in the Guadalquivir River estuary (SW Spain), with an overview of its global spread.”

The Excel file contains 16 fields: Record, Continent, Country, CountryCode, Location, Latitude, Longitude, Sampling year, Record date, Number of Individuals, Habitat, Substrate, Reference, gbifID, and occurrenceID. Records include detailed metadata on sampling site, estimated coordinates, year of detection, habitat type, and original sources. Some coordinates were inferred based on location descriptions and are marked as such.

This dataset aims to facilitate future assessments of the biogeographical expansion of M. nipponense and inform monitoring and management strategies targeting non-native freshwater decapods. It may be used for comparative invasion biology studies, geospatial analyses, or integration into global biodiversity platforms., Agencia Estatal de Investigación: PTA2022-021378-I; Junta de Andalucía: DGP_POST_2024_00956, Peer reviewed

Embryonic development represents a vulnerable life stage in marine organisms, yet its role in shaping the invasion success of non-native species under climate change remains understudied. In this study, we assessed the upper thermal sensitivity of embryogenesis of the blue crab Callinectes sapidus, a globally invasive species, by quantifying their physiological responses across a temperature gradient relevant to projected climate warming scenarios. Using Electron Transport System (ETS) activity as a proxy for aerobic metabolism, we evaluated respiration, egg size, hatching time, and larval morphology in brooding eggs incubated at 22 °C, 24 °C, 26 °C, and 28 °C. Elevated temperatures induced increased ETS activity, indicating heightened metabolic stress, and were associated with reduced egg size and earlier hatching of malformed, non-viable larvae. Within the Oxygen- and Capacity-Limited Thermal Tolerance (OCLTT) framework, we identified a physiological pejus range (24–26 °C) beyond which embryonic performance declined. These results suggest that moderate warming may accelerate development and facilitate invasion, but extreme temperatures constrain aerobic capacity and compromise larval viability. Our results highlight embryogenesis as a potential bottleneck for blue crab recruitment under future warming, with implications for predicting the invasive potential of marine species., This work was funded by the Spanish Ministerio de Ciencia e Innovacion through InvBlue project number PID2019-105978RA-I00. Financial support was given by CSIC through Intramural Research program under grant number 2024ICT027. ARR was supported by a competitive predoctoral contract granted by Universidad de Cádiz (FPU – UCA 2023). GF de C–S acknowledges the support received by the Spanish Agencia Estatal de Investigación (PTA2022-021378-I) and the postdoctoral fellowship from the Junta de Andalucía (DGP_POST_2024_00956). IH was supported by a competitive postdoctoral contract awarded by the Universidad de Las Palmas de Gran Canaria (PIC-ULPGC-2020)., Peer reviewed

Life-history traits such as reproductive potential and larval dynamics provide valuable insights into the establishment of non-native species, yet information on these traits is often scarce because of the difficulty of obtaining reproductive and larval data in both native and introduced ranges. The recent occurrence of the tropical snapping shrimp Alpheus cf . crassimanus in southwestern Spanish saltmarshes provides an opportunity to characterize its reproductive ecology in the introduced range. Using seasonal data collected over a single annual cycle, we examined variation in fecundity, egg size, female size, and larval occurrence of A. cf . crassimanus . Fecundity varied seasonally, peaking in summer, and increased with female size. Egg size was negatively correlated with fecundity, a pattern consistent with life-history strategies described for r-selected species. Ovigerous female density was highest in summer and spring and preceded peaks in larval density. Together, these results provide baseline information on the reproductive ecology and seasonal larval occurrence of A. cf . crassimanus in its introduced range. They suggest that high reproductive output and seasonal reproductive activity may contribute to its establishment, while highlighting the need for longer-term studies to evaluate the environmental drivers and broader ecological implications of these patterns., This work was partially funded by the “Consejería de Economía, Conocimiento, Empresas y Universidad, Junta de Andalucía” and EU FEDER funds through the project EcoInvadiz (P18-RT-5010). We would like to thank the OPECAM (ICMAN-CSIC) for their assistance in the field, as well as to “Parque Natural Bahía de Cádiz” and “Consejería de Agricultura, Ganadería, Pesca, y Desarrollo Sostenible, Junta de Andalucía” for sampling facilities. ARR is supported by a competitive predoctoral contract granted by Junta de Andalucía (DGP_PRED_2024_01355). MJLC acknowledges a Garantía Juvenil contract from the CSIC Program, funded by European Social Fund of UE (PEJD-02017-PRE/AMB-4296). GF de C–S acknowledges funding from the Spanish Agencia Estatal de Investigación (PTA2022-021378-I) and the post-doctoral fellowship granted by the Junta de Andalucía (DGP_POST_2024_00956), co-funded by the European Social Fund Plus (ESF+)., Peer reviewed