Marine Research Centre

ABSTRACT Introduction The pygmy sperm whale ( Kogia breviceps ) is globally distributed but considered absent in the Mediterranean Sea, with no confirmed sightings to date. Environmental DNA (eDNA) analysis offers a non‐invasive, cost‐effective, and highly sensitive tool for detecting marine species where direct observation is challenging. Methods An extensive eDNA metabarcoding analysis was conducted on 393 samples collected during the LIFE‐CONCEPTU MARIS multidisciplinary monitoring programme (October 2022–October 2024). Mitochondrial 12S‐rDNA and 16S‐rDNA amplicons were compared with reference databases and with sequences from stranded Kogia individuals from Atlantic regions adjacent to the Mediterranean and from the Mediterranean itself to ensure robust species identification. Results At least five independent detections of K. breviceps were recorded from Gibraltar to the Tyrrhenian Sea. Repeated signals and high read abundance support detection reliability. Spatio‐temporal patterns and haplotype diversity suggest the presence of multiple individuals, possible seasonal occurrence, with detections significantly associated with nocturnal sampling. Discussion The study provides the first molecular detection of K. breviceps in the Mediterranean and shows that eDNA is effective in detecting the species, possibly facilitated by the release of DNA‐rich defensive fluids characteristic of the genus. The lack of visual records likely reflects limited surface activity and historical exclusion from Mediterranean cetacean check‐lists, suggesting that some unidentified small‐cetacean sightings may correspond to this species. Synthesis and Recommendations This study highlights the value of integrated molecular, acoustic and visual monitoring and recommends enhancing multidisciplinary monitoring frameworks to better understand the distribution and ecology of this poorly known, rare and elusive species.

This paper proposes a comprehensive methodology that systematically integrates Population-Independent Analysis (PIDA) and Population-Dependent Analysis (PDA), providing both spatial hazard delineation and human risk quantification. By utilizing scenario-based simulations with varying leak diameters (5 mm, 10 mm, and 100 mm) and distinct bunkering methods (ship-to-ship, truck-to-ship, and facility-to-ship), the research elucidates fuel-specific risk profiles under diverse operating conditions. Key findings indicate that ammonia's high toxicity can produce a toxic exclusion zone extending beyond 600 m in worst-case scenarios, while compressed hydrogen often yields a similarly large hazard radius—exceeding 200 m—primarily driven by its proclivity to form flammable and explosive vapour clouds. In contrast, liquefied hydrogen exhibits a more constrained dispersal pattern, with average outer-zone radii near 25 m, albeit still presenting significant explosion hazards in enclosed spaces. These quantitative results underscore the importance of robust leak detection and rapid emergency shutdowns, which effectively reduce total leak volumes and resultant hazard footprints. The integrated PIDA-PDA framework offers distinct benefits over conventional single-method approaches. PIDA quantifies worst-case hazard boundaries for each scenario, ensuring stringent protective measures within clear safety zones. PDA then refines these zones by incorporating actual population densities and exposure rates, enabling stakeholders to prioritize areas of high casualty potential for intensified safety measures. This complementary approach avoids overly conservative restrictions while preserving critical safety margins. Ultimately, the results advance more resilient strategies for adopting LNG, ammonia, and hydrogen as viable pathways to decarbonised maritime transport. • Integrated PIDA-PDA framework for hydrogen, ammonia, and LNG bunkering safety assessment. • Scenario-based simulations quantify hazard zones for different fuel types and conditions. • Ammonia toxicity and hydrogen flammability necessitate stringent safety protocols. • Leak detection and emergency shutdowns effectively reduce hazard footprints. • Findings support safer adoption of hydrogen for maritime decarbonization.

No abstract is provided for an Editorial Paper.

ABSTRACTUnderstanding how genomic structure links with ecological and evolutionary processes is critical for forecasting species responses to dynamic marine environments, especially in commercially exploited marine species, where fishing pressure can impact genomic integrity. Here we investigate Merluccius paradoxus, a commercially exploited demersal fish that appears to be undergoing a range expansion along the southern African coastline. Using whole‐genome sequence data of individuals from across the species' distribution (n = 37), we reveal that sex‐linked divergence, rather than geography, is the principal driver of genomic variation, challenging conventional assumptions of regional geographic population structure. Divergence was concentrated on autosomal regions (primarily large regions on Chromosomes 1 and 2), rather than known sex‐determining (SD) regions (Chromosome 9), and did not have structural variants or extended linkage disequilibrium (LD). Instead, patterns were consistent with sex‐specific directional selection acting on genes enriched for neuronal function, metabolism and muscle development, traits that are likely linked to behaviour, physiology and environmental tolerance. Males had reduced nucleotide diversity (π), low observed heterozygosity (Ho) and longer runs of homozygosity (ROH) in these regions, suggesting recent selective sweeps or a reduced effective population size (Ne). Together with spatial differences in sex distribution and genomic diversity metrics, results suggest that males and females may differ in both range dynamics and adaptive potential. As M. paradoxus continues to shift its distribution across geo‐political boundaries, sex‐biased adaptation may have important consequences for reproductive output, resilience and sustainable fisheries management under a changing climate. This study highlights the need to incorporate sex‐linked genomic variation into conservation planning, particularly in transboundary systems vulnerable to cumulative pressures of fishing and environmental change.

ABSTRACTA 15‐year dataset (2005–2019) of 706 photo‐identified whale sharks (Rhincodon typus) off Praia do Tofo in Mozambique allowed us to assess the local abundance trend, and size‐ and sex‐specific sighting and abundance trends, using both generalised additive models and capture–mark–recapture models. Overall sightings per day were partially explained by temporal (year, day of year) and biophysical (sea surface temperature, time from high tide, moon illumination, Indian Ocean dipole index) predictors. There were no differences in environmental drivers between females, which comprised 26% of the study population, and males (74%). Similarly, demographic parameters (recapture probability, apparent survival, and probability of entry into the population) estimated in multi‐state open robust design capture–mark–recapture models showed no differences between sexes. Generalised additive models and multi‐state open robust design models showed a steep decline in whale shark sightings (−87%) and abundance (−89%), respectively. Female abundance was lower and decreased more sharply (−92%) than that of males (−81%), while the abundance of larger ≥ 7‐m individuals declined more (−99%) than medium‐sized (5–6.9 m, −87%) and small (≤ 5 m, −68%) sharks. This pronounced decline in one of the largest global aggregations of whale sharks highlights the pressing need for ongoing work to understand movement drivers, mitigate threats and protect this Endangered species.

Sex ratio is an important population metric in animal conservation, but its study in marine species with low sexual dimorphism is often challenging. This work aimed to apply the principles of skin mark analysis to a cetacean species to test its ability to identify sex differences in markings and build a sex-discrimination model exclusively based on photographic material. The common bottlenose dolphin (Tursiops truncatus) was chosen as the model species, and skin marks and their progression over time were identified and measured across the whole-body surface of individuals on photographs acquired between 2016 and 2023 in the Tiber River Estuary area. Interactions with fisheries were quantified both as the proportion of encounters in presence of trawlers, and as a probability of fishing gear injuries. Non-parametric tests were used to assess sex-specific differences. A generalized linear model with binary response (sex) was built through a stepwise procedure, using mark-based indices as predictors. Relevant differences between sexes emerged in markings, with males presenting more social, aggression-related, and fishing-related marks overall, and a stronger tendency of mark accumulation over time. The estimated model reflected the differences highlighted by the statistical tests and had a high accuracy and sensitivity toward both sexes. These results highlight the feasibility and efficacy of this methodological approach to sex-ratio investigations andidentify differences in anthropic pressures insisting on males and females, with important conservation implications. The exclusive use of photographic material makes this methodology potentially applicable and adaptable to multiple species and environments, aiding the efforts of conservationists worldwide.

Practical application of the

The reduction of atmospheric CO2 through its safe geological storage, as CCUS techniques is one of the goals to achieve the 2050 commitment. Within the scope of the PILOTSTRATEGY project, two sedimentary sequences Triassic (on-shore) and Cretaceous (offshore) were object of a detailed study in order to evaluate their potential as CO2 storage complexes in the Lusitanian basin (west Portuguese margin).A multi-disciplinary, multi-analytical approach was applied to the potential reservoirs and caprock samples to their characterization. The obtained results (XRD, TGA, petrography) reflect the predominance of siliciclastic composition of the reservoirs (mainly quartz and K-feldspar) whereas the caprock exhibit a carbonate (mainly calcite) (Cretaceous) or gypsum (Triassic) composition.Several batch reaction experiments were carried out at Edinburgh University (UEDIN). Samples from the Cretaceous storage complex reacted with a NaCl brine injected with CO2 at controlled P=100bar, T=40°C conditions   for 30days during which the chemical composition of the brine was regularly analysed. The elemental variations of the brine reacting with the reservoir samples reflect the dissolution of the present mineralogical phases, namely the K-feldspar, pyrite and clay minerals, and in some cases the precipitation of new phases, such as opaline silica.The composition of the brine reacting with the caprock, registered an increase in Ca content at the first 2 days, interpreted as being the result of the limestone dissolution, without further variation throughout the experiment with a constant pH (6.36-6.57).The identification of newly formed phases and evidence of dissolution as future and ongoing work are fundamental in understanding the entire process and predictability of the reservoir and sealant.The work is funded by H2020 – STRATEGY CCUS (grant No. 837754)and national funds through FCT – Fundação para a Ciência e Tecnologia, I.P., in the framework of the UIDB/04449/2020 and UIDP/04449/2020 – Laboratório Hercules; UID/04292 - MARE-Centro de Ciências do Mar e do Ambiente and; UIDB/04683 and UIDP/04683 – Instituto de Ciências da Terra program.