In the life of the endangered but still fished Anguilla anguilla, glass eels are recruited through estuaries. These fragile ecosystems are among the most disturbed on the planet. Here, heavy metals and microplastics were measured in estuary water and European glass eels entering bay of Biscay rivers of different size and anthropogenic stress. Eels from all the estuaries exhibited cadmium exceeding legal European limits, as happened with lead in samples from the highly disturbed Avilés estuary. Several water samples from small rivers surpassed the estimated limit of microplastic for ecotoxicological safety. In multiple regression analysis, both eel lead and microplastic content were significantly explained from shipping activity in the estuaries. Eel cadmium content was not associated with estuary stressors, being probably acquired during the oceanic migration of eel larvae. The presence in eels of new white polyethylene particles that had not been found previously in the region could be explained from the marine plastic spill of "Toconao" cargo in December. The same spill could explain a significant increase of microplastic bioconcentration in the glass eels in comparison with previous surveys. These risks for critically endangered eels, and for the consumers, highlight the urgent need for reducing the impact of contaminants on both local and global scales.

Maritime traffic accounts for more than 90% of world trade. Noise, pollution, and litter are its drawbacks, affecting especially vulnerable migratory fish. Here, a motivated team of citizen scientists analyzed maritime traffic from three estuaries of the south Bay of Biscay and three from the south of the Iberian Peninsula, where the European eel is critically endangered, during the season of the entrance of glass eels. More than 164,000 data points about ship types and positions were collected. The results showed that traffic differences between estuaries would explain, at least partially, the different eel conservation statuses. The participants appreciated learning about ships and nature conservation and acquiring an awareness of the real volume of shipping and its potential impacts. All the citizen scientists, new and experienced, would like to get involved in ocean research again.

The maritime industry is experiencing a critical shortage of qualified officers, partly associated with the demanding psychosocial conditions of seafaring. While Maritime Education and Training (MET) has traditionally emphasized technical competencies, psychological preparedness has received comparatively less attention in maritime curricula. This study presents a multi-cohort evaluation integrating the assessment of personality, mental health, workload, and fatigue in maritime students with the design and evaluation of psychoeducational interventions embedded in MET. Using a sequential cross-sectional mixed-methods design across three consecutive academic years, successive student cohorts were assessed using validated instruments, including the 16PF-5, GAD-7, PHQ-9, WHO-5, NASA-TLX, and SOFI-SM. Students generally showed adaptive psychological profiles, although a meaningful minority reported moderate-to-severe anxiety or depressive symptoms. Perceived workload and fatigue differed significantly across academic activities, with lower levels during practical sessions; shorter sleep duration was associated with greater perceived strain. Psychoeducational activities, including seminars, workshops, and conferences on maritime psychology, were positively evaluated by participants and perceived as relevant to their professional development. These findings support the feasibility and educational value of integrating structured psychoeducation, fatigue awareness, and mental health promotion into MET curricula, contributing evidence relevant to ongoing discussions surrounding the revision of the STCW Convention.

Maritime traffic accounts for more than 90% of world trade. Noise, pollution, and litter are its drawbacks, affecting especially vulnerable migratory fish. Here, a motivated team of citizen scientists analyzed maritime traffic from three estuaries of the south Bay of Biscay and three from the south of the Iberian Peninsula, where the European eel is critically endangered, during the season of the entrance of glass eels. More than 164,000 data about ship types and positions were collected. Results showed that traffic differences between estuaries would explain, at least partially, the different eel conservation status. The participants appreciated learning about ships and nature conservation and acquiring awareness of the real volume of shipping and its potential impacts. All the citizen scientists, new and experienced, would like to get involved in ocean research again.

Citizen science and environmental DNA (eDNA) are increasingly used to detect and monitor invasive species in freshwater ecosystems, yet their combined application to investigate invasion drivers and spread has rarely been explored in southern Europe. In this study, we integrated both analyses to assess the expansion of the invasive signal crayfish Pacifastacus leniusculus in Asturias rivers (northern Spain), where the species was first recorded in 2013. Citizen scientists collected and filtered 69 water samples from 39 sites for eDNA extraction, and recorded visual observations, physico-chemical parameters and anthropogenic litter. Signal crayfish-specific nested PCR detected presence at 15 of the 39 sites (38.5%), including locations absent from official records, particularly in coastal reaches and headwater streams. Signal crayfish DNA was significantly associated with fishing litter, suggesting intentional introductions by recreational fishers. It occurred more frequently in sites with high chloride concentration, consistent with the species' tolerance to disturbed environments. More frequent detection from coastal reaches than in midstream or headwater sections suggested a downstream colonization gradient, but when corrected by the connectivity between basins it points to human-mediated introductions rather than natural dispersal. Overall, our results show that integrating citizen science, eDNA and litter assessments provides an effective approach for identifying invasion fronts and potential introduction pathways, supporting the management and control of this globally invasive species.