ABSTRACT. Elasmobranchs (sharks, skates, and rays) are one of the oldest animal groups on the planet, having first appeared over 450 million years ago, before trees and before Saturn had rings. Important evolutionary innovations such as closing jaws and live birth first appeared in ancestors of sharks and their relatives, as well as the prototype cellular mechanisms of our own mammalian adaptive immune system. As top predators, extant sharks play a vital role in preserving the health of the world’s oceans, but have among the slowest growth and reproductive rates in nature- more like humans or whales than like other fishes- and as a result are particularly vulnerable to disturbance. Alarmingly, recent studies show that shark abundance has declined >70% in just the past 50 years, and over a third of remaining species are at risk of extinction. Despite major conservation concern, relatively little is known about the biological factors influencing the long-term viability of shark populations, including how they adapt to environmental challenges. Now, global warming is altering the marine environment in unprecedented ways, and many species are facing an uncertain future. In this talk, we explore what an animal lineage that has outlasted five major global extinctions can teach us about surviving climate change, and how scientists are harnessing the power of their ancient immune systems to preserve shark populations into the future.

ABSTRACT. Abstract

Aim With two million species described, it is still unclear how far we have gone in the inventory of Earth diversity. The number of existing species is estimated around 10–100 mln, with large uncertainty due to understudied phyla. Since the application of molecular biology in systematics, it became possible to detect species that could not be discovered by traditional morphological means. The impact of this “cryptic diversity” on global estimates has been investigated only in a few recent studies on insects. By analysing literature data, these studies hypothesize that the number of insect species could be 3 to 6 times larger than expected. We propose a different empirical approach for weighting the impact of cryptic species focusing on the class Gastropoda.

Methods A large sampling dataset of over 5000 gastropods collected in Corsica during the CORSICABENTHOS expedition, which received both morphological and molecular identification, was analysed to measure the Cryptic Diversity ratio (CD-ratio), i.e. the number of expected cryptic species per morphospecies in a given taxon. Results from this method were compared with CD-ratio estimates obtained by scrutiny of literature on species delimitation.

Results This large-scale barcoding project disclosed previously unrecognized cryptic diversity, while also establishing the taxonomic status of debated species. The resulting CD-ratio is >1, yet lower than the one extrapolated from literature data.

Main conclusion Despite the Mediterranean being a very well-studied marine bioregion, our analyses confirm that cryptic diversity does impact global marine biodiversity estimates. However, the magnitude of such impact cannot be adequately inferred from literature meta-analyses. Finally, CD-ratio has surely a large geographic and taxonomic variance, making extrapolations to a global scale problematic. Revision of neglected taxa by Integrative Taxonomy approaches remains needed to understand the real impact of cryptic diversity on the global diversity estimates.

Thematic Areas Macroevolution, Biodiversity

ABSTRACT. Seahorses (Hippocampus spp.) are flagship animals inspiring numerous conservation programs. They are the first marine genus to be fully listed on the Convention on International Trade in Endangered Species (CITES) Appendix II due to their substantial vulnerability to overexploitation and habitat loss. The peculiar life history of these fishes has been widely addressed through evolutionary and ecological analyses. Yet, no study has integrated current knowledge to approach species-based conservation status, including trends in abundance, diversity, and threats, hindering seahorses’ worldwide effective assessment and management. Here, we bridge these gaps by taking advantage of the available geographic, ecological and genomic (ultra-conserved elements and whole genomes) data in the Hippocampus species at a global scale, and present the most comprehensive study of the seahorses’ conservation status to date. Specifically, we explore species distributions and perform ecological niches modelling, phylogenomic mapping, comparative genomic applications, demographic inferences, and conservation gap analyses. We consider their evolutionary history, demographic changes and genomic erosion including genetic load, which have been largely disregarded by current conservation policies. We investigate the degree and type of protective measures currently granted to seahorses, and the biological and ecological factors that are contributing to their existing and future extinction risk. Our results raise questions on whether the current conservation indicators and practices are effective in preserving the present diversity and function of these iconic fishes, as well as their future evolutionary potential and ecological resilience. These insights provide a broad, more complete picture on the status and trends of seahorses and inform successful conservation initiatives. Finally, as more diverse datasets become available in the light of the “omics” and “open-access” era, we discuss the unprecedented opportunities to address interdisciplinary studies required for proper research-based conservation, assessment, and management of biodiversity.

ABSTRACT. Population bottlenecks are likely to have genome-wide negative consequences due to increased genetic stochasticity and lower efficacy of selection, resulting in the loss of adaptive variants and an increase in the frequencies of deleterious variants. The worldwide fin whale (Balaenoptera physalus) was intensively exploited by commercial whaling, and present populations differ significantly in abundance, connectivity, and history, providing a unique opportunity to analyse the impact of past demography on genomic composition. Despite their global presence, fin whales rarely traverse the equatorial areas, hence their range is defined by the equator and major landmasses. In some productive warm-water regions, smaller resident populations can be found in semi-enclosed seas like the Mediterranean and the Sea of Cortez (Gulf of California, Mexico). Here, we provide a new reference genome and examine genomic erosion on fin whales from the two semi-enclosed basins. In particular, we sequenced and examined for the first time the genomes of 13 fin whales from the Mediterranean Sea and inferred the degree of genomic isolation from the related North Atlantic population. For comparison, we sequenced and analysed seven genomes from the Sea of Cortez, known for its geographic and genetic isolation, and contextualized our newly generated data with samples from the North Atlantic (Iceland and Svalbard), already available in the literature. Our results support that fin whales from the Mediterranean Sea are not isolated but appear to be part of a larger population with fin whales from the North Atlantic. We revealed an overall genomic erosion in the small and isolated Sea of Cortez population, with lower levels of genetic diversity and longer runs of homozygosity, while no such genomic erosion was detected in the Mediterranean Sea population. More investigations are focusing on the genetic load of these populations, which is expected to improve current conservation policies and management. These findings will provide a more comprehensive picture of the status and trends of fin whales and help to guide successful conservation efforts.

ABSTRACT. Aim For decades, phylogeographic studies of marine turtles have relied on comparisons of partial mitochondrial DNA (mtDNA) control region sequences. The limited resolution of this marker due to common haplotypes being shared across populations, has hampered a comprehensive description of lineages and the assignment of turtles of unknown origin to their rookeries. Analysis of whole mtDNA provides a tool for a better characterization of matrilines. We applied a mitogenomic approach to the phylogeography of the loggerhead turtle (Caretta caretta), a conservation-dependent species in the Mediterranean Sea. Methods Mitochondrial genomes of 61 C. caretta individuals sampled in the central Mediterranean Sea were sequenced by synthesis at high coverage on an Illumina NovaSeq 6000 platform. Five additional loggerhead mitogenomes from the Atlantic and Pacific Oceans were also included in the alignment. We assigned mtDNA haplotypes and haplogroups. We then estimated population genetic diversity for mtDNA control region and complete mitogenome haplotypes and performed Maximum Parsimony and Bayesian phylogenetic analysis. Results We recovered 23 mitogenome haplotypes and 286 polymorphic sites versus 10 haplotypes and 55 polymorphic sites obtained by analysis of partial mtDNA control region sequences alone. In particular, the common mtDNA control region haplotype CCA2.1 presented 11 mitogenomic variants. Phylogenies showed that the Mediterranean/Atlantic haplogroup expanded recently with respect to the time of divergence from the sister clade - the Pacific haplogroup - and the Atlantic haplogroup. Main conclusion Whole mitogenome sequencing proved a powerful tool to better characterize maternal lineages of C. caretta and reconstruct phylogenetic relationships. Application of mitogenomic studies to a comprehensive dataset representing the main Mediterranean, Atlantic and Pacific populations will allow detailed reconstruction of worldwide dispersal and colonization patterns of loggerhead turtles.

ABSTRACT. The intrigue of fish hybridisation holds profound implications for both the fundamental principles of biology and practical conservation and management efforts. Despite evidence of its pervasiveness, the phenomenon of hybridisation in fish is not uniformly studied across species and environments. We unveil a consistent underestimation of hybridisation in these groups, shedding light on a critical blind spot. We note how natural hybridisation in pelagic and deep-sea fish has been rarely reported. For this reason, we carry out an analysis using both standard and phylogenetic comparative methods. Our results suggest a lack of evidence for the idea that pelagic and deep-sea fish are inherently less prone to hybridise. Likely, hybridisation and introgression are systematically underestimated in these groups. In light of this, we discuss why underestimation of hybridisation is problematic, and what it may be done to ameliorate the situation. We propose scalable and cost-effective prioritisation, sampling, and analysis strategies, to ease existing biases in assessing the impact of hybridisation among pelagic and deep-sea species and to ultimately improve the management and conservation– as well as basic biological knowledge – of these important species. Our work calls for a shift in perception and action, inviting a holistic approach to studying and safeguarding these vital species.

ABSTRACT. Aim From the beginning of the industrial era, ocean has globally absorbed more than 500 billion tons of CO2. As a major consequence of such event, seawater has become more acidic and has undergone major changes in its carbonate chemistry, leading to the phenomenon commonly known as Ocean Acidification (OA). Species of the genus Patella Linnaeus, 1758 are shelled gastropods mostly living in the intertidal area. Despite of the effects that a decreased pH has on calcifying organisms, these taxa thrive also under naturally acidified conditions. We hereby investigated the biochemical and molecular mechanisms that allow survival and adaptation of these species at the CO2 vents of the Castello Aragonese (Ischia Island, Tyrrhenian Sea). Methods Individuals of Patella caerulea, P. rustica, and P. ulyssiponensis were collected in February 2023 along a pH gradient on the north site of the Castello Aragonese vent system, as well as at San Pietro, located at a distance of 4 km from the vent and characterized by ambient pH. Morphometric characteristics, oxidative stress, energy metabolism, and neurotoxicity endpoints were investigated in the three species, whereas physiological traits and untargeted metabolomics in P. caerulea only. Results An induction of some oxidative stress endpoints was observed in all the species. A modulation of the acetylcholinesterase activity was found in P. ulyssiponensis and P. rustica as a function of pH, while glycogen content was higher in P. cerulea and P. rustica from the lower pH site with respect to the ambient site. Metabolomics revealed a significative modulation of different metabolites, mainly linked to carnitine metabolism in specimens living in acidified conditions.

ABSTRACT. Aim The increase in sea surface temperature (SST) and in the occurrence of extreme climatic events are affecting marine ecosystems at multiple levels. To overcome the continuous environmental changes, seagrasses have developed adaptative strategies such as changes in patterns of sexual reproduction, distribution shifts, and morphological changes that allow to maintain the provision of goods and services. Past studies highlighted that flowering and fruiting events of the endemic seagrass Posidonia oceanica have been increased in the past decades in the Mediterranean Sea, and this study aimed at investigating the role of the high temperature on these phenomena.

Methods To shed a light on the thermal conditions that might trigger flowering, the relation between several thermal descriptors and P. oceanica flowering and fruiting variables were tested in this study, gaining data from five areas in Sardinia (Italy) in Autumn 2022 and Winter 2023.

Results Results suggested that mean summer SST was positively associated to inflorescence density, presence of living fruits and fruit size; living fruits and fruit size were also affected positively by the maximum SST within the 3 months before sampling (November-February). Both flowering and fruiting were negatively affected by the maximum SST within one month before inflorescence observation and mean winter SST, respectively.

Main conclusion Overall, this study suggested that P. oceanica reproductive effort depends on the temporal context in which the anomaly occurs and its duration. However, the high variability between meadows of the same area indicates the important role of local factors in affecting flowering that still need to be highlighted.

ABSTRACT. Aim Overfishing has altered marine food webs in European waters, including top predators’ trophic ecology. The common dolphin is one of the most abundant cetaceans in the North-east Atlantic, playing a key functional role. A decrease in body conditions has been observed in the past, suspected to be related to changes in fish stocks. The aim of this study was to advance the study of common dolphins’ dietary shifts by assessing the feasibility of molecular approaches (metabarcoding) for diet analysis from stomachs of dead stranded animals.

Methods Stomach content analysis was carried out from 84 dead stranded individuals. Dissection protocols have been adapted to allow the collection of environmental prey DNA alongside with hard parts for conventional identification of contents and parasites. Subsequently, DNA was extracted and processed for Illumina sequencing using teleost (fish) and cephalopods (squid) specific markers for 16S and COI region.

Results The method applied was able to successfully provide sequencing data, unravelling diet composition of a high proportion of stomach contents originating from animals in different conditions. Multiplexing markers served well in generating output while conserving resources and the efficiency of the different markers will be discussed. During analysis, the detection of a range of species of fish and squid originating from different taxa is expected.

Main conclusion Identifying diet composition and trophic ecology of top predators through metabarcoding is feasible using samples of stranded cetaceans. A successful protocol of sample treatment has been developed based on the adaption of previous employed techniques of Illumina Sequencing and is recommended for future use with advantages in comparison to a previous first approach in literature. Results of the analysis will be used to complete conventional diet analysis to identify dietary shifts and to compare conventional and molecular stomach content analysis.

ABSTRACT. Citizen science and spatial ecology analyses can inform species distributions, habitat preferences, and threats in elusive and endangered species such as seahorses. Through a dedicated citizen science survey submitted to the Italian diving points, we collected 115 presence records of the two seahorses occurring in this country, Hippocampus hippocampus and H. guttulatus. This data was then used to map the ecological features of these poorly known species and quantify the effects of current human activities on their habitat suitability through geographic information systems and ecological species distribution modelling. Our results indicated a quite continuous suitable area along the Italian coasts with a major gap in the central Adriatic Sea (Emilia-Romagna and Marche) in both seahorses. They co-occurred in most of their distribution, particularly in the central and southern Tyrrhenian coasts, and their ecological niches resulted to be significantly similar but not equivalent. The least-cost paths of both species were concentrated in the Southern Italy (Apulia, Calabria, and Sicily), suggesting that more data is needed to improve the spatial resolution of the available information, especially in the Northern and Central Italy. Human activities affected 35% and 41% of the H. hippocampus’ and H. guttulatus’ habitat suitability, respectively, while only 31% and 34% of their potential distribution, respectively, is protected by the existing system of conservation areas in Italy, in line with the seahorses’ worldwide average. In particular, the central Adriatic Sea represents a critical area where the occurrence of these seahorses is lower and the anthropic impact is higher. Considering all the Italian regions, fishing effort is the main human activity impacting both the seahorses. Our findings directly assist more efficient conservation actions. We encourage the application and interaction of citizen science and spatial ecology analyses to facilitate the assessment and sustainable management of elusive organisms.

ABSTRACT. Aim Alien Invasive Species (AIS) pose a significant threat to marine ecosystems, and can cause irreversible damage to the environment, native species, and human welfare. One of these species, Caulerpa cylindracea, has rapidly spread in the Mediterranean Sea, affecting biodiversity and ecosystem functioning. In this study, the future spread of C. cylindracea in the Mediterranean Sea under changing climatic conditions is predicted. Methods Using high-resolution oceanographic and environmental data derived from IPCC-AR5-RCP8.5 based MEDSEA-PHYSICS and MEDSEA-BIOGEOCHEMISTRY simulations and EMODnet Seabed Habitats. Species occurrences data were derived from the Reef Check Med Dataset and EASIN - European Alien Species Information Network dataset. The dataset contained physical, biogeochemical and biological data at a spatial resolution of 1/24 degree and a yearly time resolution from 2000 to 2050. A Maximum Entropy (MaxEnt) spatial distribution modeling framework was implemented, using the best available techniques, to create predictive models for the future spreading of this invasive alien species. In particular we used six commonly used performance metrics (AICC, AUC, SEDI, CBI, OR.10p, AUCDIFF) to evaluate the model performances of 1240 models configurations obtained by varying models parameters and combine the results. Results Our results show the potential distribution of C. cylindracea under current and future climatic conditions. Main conclusion Results suggests a plateau-like invasion kinetic (sometimes referred as natural fluctuation model) in the currently suitable areas, with no sign of widespread suitability increase in the near future.

Thematic Areas Conservation, Populations and Species

ABSTRACT. Aim The strategic location and hydrological-climatic history of the Mediterranean Sea make it a biodiversity hotspot, prompting extensive studies in this region. However, distributional data for Mediterranean taxa are scattered across various sources and formats, including articles, datasets, and non-digitized biological collections, yielding a loss in information. Retrieving and harmonizing these scattered data could facilitate their use for biodiversity research and conservation. The aim of this work is to provide a standardized pipeline to integrate these dispersed dataset of Italian marine species occurrences, using molluscs as a proxy.

Methods Data were gathered from two main sources: published literature and biological collections. Occurrence records were defined as those containing at least an identification and a location. The harmonization process involved four key steps: 1) taxonomy updating, 2) terminology and structure standardization, 3) conversion of dates to ISO 8601 format, and 4) transforming textual localities into spatial points with coordinates and a degree of uncertainty, following a standardized workflow. Each record then underwent a quality check to assess its usability.

Results Our efforts yielded over 30,000 standardized records of marine molluscs in Italian waters. These records encompassed newly digitized specimens from 10 different institutions and private collectors, as well as data extracted from more than 70 published studies. The most represented groups were gastropods and bivalves. The dataset also included information on alien, rare, and endemic species.

Main conclusion The integration of published and unpublished data may provide a comprehensive spatial and temporal overview of Italian marine malacofaunas. This approach can shed light on under-sampled areas and taxa, guiding potential avenues for future studies.

ABSTRACT. Abstract Aim

Ascidians are tunicates possessing mechanoreceptors potentially able to respond to water particle motions caused by underwater noise. These mechanoreceptors include both epidermal neurons, mainly located around the siphons, and receptors on oral tentacles, called coronal cells. CCs are homologues of vertebrate hair cells, therefore potentially sensible to noise. The latter is known to negatively affect some marine vertebrates. However, the ability of most invertebrates to tolerate and adapt to this environmental stressor are still largely unknown. Within the DeuteroNoise project (financed by JPI Oceans), we analyzed the effects of anthropogenic low-frequency noises, i.e. those generated by maritime traffic, on the colonial ascidian Botryllus schlosseri (Pallas 1766). Methods We performed two kind of noise treatments (duration: 30 min; 63-125 Hz; sound pressure level 160dB), using 1) a continuous noise and 2) an intermittent noise. To evaluate the noise effects, we used behavioral tests. The siphon stimulation test involves the oral siphon receptors, whose stimulation induces the oral siphon contraction. The tentacle stimulation test regards the coronal cells that, when stimulated, evoke the atrial siphon closure. The two tests evaluated the sensory cell ability to respond to a controlled mechanical stimulation before and after the noise treatments. Each test was accompanied by heartbeat counting to assess the potential effects also at physiological level. Treatments were performed in triplicates; untreated colonies (genetically identical to treated colonies) were used as control. Data were statistically analyzed. Results The continuous stimulation had negative effects at both behavioral and physiological level, significantly decreasing animal sensitivity and decreasing the heartbeat frequency; vice versa, colonies showed no effects when treated with intermittent noise.

Main conclusion

B. schlosseri is affected by the applied continuous noise. To improve our conservation policies, future experiments will be performed to verify if there is a threshold level negatively affecting these animals.

ABSTRACT. Aims Phytoplankton plays a key role in marine food webs and in the neritic and pelagic ecosystems as, being at the base of it, can influence the availability of trace elements. However, above a certain level essential and non-essential elements could cause damage to the marine ecosystem, and reaching higher levels of the food web could also cause toxicity risks for humans. The study aims to investigate the presence of REEs and trace metals at different depths in phytoplankton populations from the Ligurian Sea to understand if these components, which represent a truly important link in the food web, can be used as bioindicators to detect the presence of these elements in the marine ecosystem. Methods The phytoplankton was collected in the four seasons (Spring, Summer, Autumn, and Winter 2021) at two different depths (-30 m and -50 m). with a mesh size of 20- microns (diameter of 40 cm), frozen at -18 °C, and stored in dark glass bottles. Trace and rare earth elements were analyzed by inductively coupled plasma spectrometry (ICP-MS) after microwave mineralization with nitric acid and oxygen peroxide. Results The results show that trace elements and REEs have a higher concentration at 30 m of depth, apart from Fe, Zn, Mn, and V which appear to be more concentrated at 50 m. Moreover, we have also noticed that both trace and REEs were recorded at the highest levels in the winter season and lowest in spring. Main Conclusion The presence of inorganic compounds in the first meters of depth can be attributed to some biochemical processes, such as the absorption of phytoplankton in surface waters and the decomposition and demineralization of organic material in deep waters. Fe and Zn have higher concentrations than other elements as they are involved in the fixation of C and N and in the electron transport chain for photosynthesis.

ABSTRACT. Abstract Aim The increase of anthropogenic CO2 in the atmosphere is one of the main drivers of global change in the oceans, leading to an increase in temperature and ocean acidification (OA). Areas naturally enriched in CO2, such as volcanic vents, have been used to study the effects of future acidification on marine ecosystems. Seagrasses are important habitat formers, and Posidonia oceanica is the endemic and most widespread species in the Mediterranean that can also colonize high pCO2/low pH habitats. Here we summarize the studies conducted in hydrothermal vents on P. oceanica and its associated fauna to shed light on adaptive responses to OA.

Methods A bibliographic review was conducted for a total of 18 selected references.

Results Posidonia oceanica responds to high pCO2 with an increase in primary production and shoot density as well as in leaf growth, height and thickness. However, under some extreme conditions in the Panarea vents, dwarf shoots were described with a biomass up to 75 % lower than normal shoots. Alteration in stable isotope signature and higher C/N ratio were measured in the leaves, possibly explaining the high grazing pressure by the herbivore fish Sarpa salpa. A simplified epiphytic community with a strong decrease of all calcareous forms occurred in various systems, while the motile fauna showed higher abundances and comparable biodiversity respect to normal pH conditions. Finally, P. oceanica meadows are able to modify pH up to 0.5 pH units daily through photosynthetic activity and community metabolism, providing a chemical refuge for associated fauna.

Main conclusions The summarized adaptive responses to OA in Posidonia have far-reaching direct and cascading effects on associated communities and ecosystem services. Since not all the responses were univocal and predictable (e.g. dwarf shoots), further studies on OA and synergistic effects of other stressors on this habitat are essential to unveil the mechanisms of its survival.

ABSTRACT. Aim Coral reefs worldwide are currently under multiple threats due to increase sea surface temperature and other abiotic, biotic, and anthropogenic factors. In particular, Singapore’s reefs suffer from high sedimentation and low light penetration as a result of extensive land reclamation coastal development since the 1960s. Underwater visibility in the Singapore Strait has reduced from >10m in the early 1960s to ~2m today, with average daily photosynthetically active radiation (PAR) levels at ~6m depths reaching <50 µmol m-² s-1. The current study aims to investigate the effects of extreme low-light stress on the photo-physiology of the common Singapore’s species Pachyseris speciosa.

Methods Four different colonies of P. speciosa were sampled from Kusu Island, a reef site in the Singapore Strait, and 16–18 fragments were obtained from each colony. These fragments were subjected to three different light treatments for 4 weeks; 1) Control – normal light conditions (PAR = 16.4 ± 38.5 µmol m-² s-1); 2) Intermittent – 5 days of normal light and 2 days of total darkness; 3) Dark – always fully shaded in total darkness (PAR = 0.8 ± 8.0 µmol m-² s-1). Photo-physiological (zooxanthellae density, chlorophyll concentration, and PAM fluorescence) and transcriptomic data were recorded from every fragment at the beginning and at the end of the experiment. In addition, colour monitoring of all fragments was done twice a week.

Results After a 4-week experiment, all 68 fragments of P. speciosa survived. Chlorophyll concentration, zooxanthellae density, health and MQY showed a significant decrease in the shaded treatment. Respectively, they decreased by 67% p<0.01, 71% p<0.01, 58% p<0.01, 22% (p<0.01).

Main conclusion Overall, our findings suggest that P. speciosa is very robust to low-light stress and thereby a good candidate for use in restoration in low light environments such as those found at nearshore reefs or at deeper reef zones around Singapore.

ABSTRACT. Aim MicroRNAs (miRNAs) are small non-coding RNAs that can regulate gene expression post-transcriptionally by interacting with mRNAs. They are fine tune modulators that have a pleiotropic effect, interacting with different targets. Their expression is reported to vary according to external stimuli, triggering cellular responses and metabolic adjustments, becoming important modulators in the adaptation to environmental conditions or stress. Remarkably, a few or even a single miRNA can be used to diagnose stress response, which makes them particularly attractive as potential indicators of population-level stress responses.

Methods We selected the microalga Phaeodactylum tricornutum in order to observe the differential expression of miRNAs under three different stress conditions: low salinity, nitrogen deprivation, and metals contamination (Cd + Pb). We selected these conditions because could represent some environmental changes that are important to be monitored. Specifically, the total RNA of the microalga under all the conditions and control condition has been extracted and then sequenced by small-seq TruSeq (Illumina) in order to construct small RNA libraries.

Results We will identify miRNAs via mapping on miRbase to find the already known ones and the possible conserved ones (by also using miREvo). The mapping of unknown sequences on the P. tricornutum genome will allow the discovery of novel miRNAs via the use of bioinformatic tools (such as miRDeep2). Furthermore, it will be analysed the Differential Expression of the miRNAs (DEMs) in each condition and possible direct targets will be predicted (via the use of psRNATarget, miRanda, psRobot) and validated.

Main conclusion This study will be helpful in the elucidation of the molecular adaptation of diatoms to different environmental stresses and in the identification of novel molecular biomarkers.

ABSTRACT. Abstract Aim Marine Protected Areas (MPAs) provide protection populations and ecosystems, while allowing for a regulated resources’ use, e.g., fishing. The time scale required by biological systems to respond to protection measures (i.e., the reserve effect) poses a big challenge in the MPAs management. Assessing early responses to protection is therefore crucial to adjust MPAs design and maximize their performance over time. The extent and the timing of populations’ recovery is influenced by species life histories and ecological traits. Here, we evaluated the reserve effect at the Cinque Terre MPA (Italy) on the whole rocky reef fish community also by grouping species according to their traits’ similarity to better interpret their recovery trajectories.

Methods We analysed biomass data of the rocky-reef fish community outside and within the three protection levels of the Cinque Terre MPA. We then built a matrix of species life history and ecological traits potentially influencing populations’ response to protection (i.e., planktonic phase duration; commercial value; mobility etc.). Finally, biomass data trends have been re-analysed by pooling species according to traits’ correlations.

Results Traits’ analysis showed that species clustered into three groups characterized by differences in mainly four traits: prey guild, planktonic phase duration, gregariousness, and commercial value. Species feeding on high trophic levels, having long planktonic larval development, intermediate level of gregariousness and high commercial value showed a significant response to protection, while other groups demonstrated a limited reserve effect or none.

Main conclusion Traits’ analysis allows to disentangle the complex ecological interactions that could mask populations’ recovery. Grouping species based on their traits’ similarity could help in assessing early responses to protection, whilst allowing to adjust MPA measures, maximise their effectiveness and simplify their management. Overall, traits’ analysis has the potential to become a crucial tool to study fish population responses to MPA protection.