A series of sampling activities in the Tyre Coast Nature Reserve, on the Southern coast of Lebanon, in the context of the project Blue Tyre - Local Partnership for Sustainable Marine and Coastal Development, allowed for the collection of material to study the polychaete fauna of the area, with particular focus on Non-Indigenous Species (NIS). The detection of several taxonomical novelties resulted in the description of five new species belonging to four families: Dorvilleidae, Eunicidae, Nereididae, and Sabellidae. Based on clear differences compared to the historical polychaete fauna of the Mediterranean Sea and on the presence of morphological similarities or genetic correspondence with Indo-Pacific taxa, we suggest that, despite having Mediterranean type locality, the newly described species should be considered NIS in the Mediterranean. Thus, the present data reaffirm the importance of the Levantine Sea and the Lebanese coast as an outpost for the early tracking of bioinvasions in the Mediterranean area. Specific epithets of Pseudobranchiomma Jones, 1962 species are amended to their correct Latin gender, following article 30.1.2 of the I.Z.C.N. Lastly, a review of the available literature on both the genera Nereis Linnaeus, 1758 and Lysidice Lamarck, 1818 reveals the necessity of corrections to the taxonomic status of some species within these genera.

We present a genome assembly from an individual Hermodice carunculata (bearded fireworm; Annelida; Polychaeta; Eunicida; Amphinomidae). The genome sequence has a total length of 2 103.51 megabases. Most of the assembly (90.04%) is scaffolded into 19 chromosomal pseudomolecules. The mitochondrial genome has also been assembled, with a length of 15.87 kilobases. This genome was generated as part of the Aquatic Symbiosis Genomics Project.

Taxonomists in the 19th and early 20th centuries described several species of Myxicola Meneghini, 1847 in Europe. Until recently, all historical taxa were considered synonyms of M. infundibulum. Using an integrative taxonomic approach-combining molecular phylogenetics and morphological re-evaluation of museum samples, and newly collected material from the Mediterranean Sea and Macaronesia-we uncovered significant diversity within this genus. Phylogenetic analyses based on three molecular markers reveal that Myxicola comprises two highly supported and deeply divergent clades. The morphological synapomorphies unique to one of these clades, reported for the first time for Sabellidae as a whole, led to the establishment of Paramyxicola gen. nov. We confirm the distinction of M. cosentini and M. giuliae from M. infundibulum, while M. cataldoi is identified as junior synonym of M. infundibulum. We describe two new species of Myxicola (M. albertoangelai sp. nov. and M. pirainoi sp. nov.) and two new species of Paramyxicola (P. mariacristinae sp. nov. and P. marielouisae sp. nov.). We synonymize M. polychroma with M. modesta and report it, together with M. cf. fauveli, in the Mediterranean Sea for the first time. The biogeography and distribution of species in these genera are discussed, with emphasis on their possible evolutionary history.

Biofouling communities are usually managed as pests in aquaculture, yet their natural proliferation in fish farms makes them also promising IMTA extractive components. The growth and biomass production of four dominant macrofoulers, Mytilus galloprovincialis (mussels), Sabella spallanzanii (polychaete worms), Phallusia mammillata and Styela plicata (ascidians), were evaluated under a novel IMTA system in the Ionian Sea (southern Italy). Coconut-fiber ropes (10 m) were deployed around fish cages in October 2022 and monitored over a 1-year cycle. Monthly density, length-frequency and cohort analyses combined with species-specific length-weight relationships were used to estimate target species’ growth and biomass. Mytilus and Sabella showed single-cohort dynamics, with densities steadily declining over time, whereas ascidians displayed continuous recruitment allowing for additional rope-deployment windows. Specific growth rates in length were significantly higher in Phallusia and Sabella (≈25% month−1) than in Mytilus and Styela (≈17 and 22% month−1). Total macrofouling biomass (live weight) increased from ≈350 kg in May to a peak of ≈2500 kg in August, remaining as high in October. Mytilus and Sabella accounted for 60–80% of total biomass while ascidians contributed 20–40%. Beyond environmental restoration, this multispecies biomass offers several potential commercial opportunities and could be further valorized through biorefinery-based cascading extraction, including final conversion into bioenergy. Overall, IMTA could leverage traditionally undesired fouling organisms as multifunctional crops, enhancing bioremediation while supporting circular blue-bioeconomy principles. Future research should focus on optimizing rope deployment timing, harvesting strategies, and biomass valorization pathways to fully exploit the emerging potential of integrating multispecies fouling biomass within IMTA systems.

The cultivation and biomass production of the worm Sabella spallanzanii (Gmelin, 1791) through local macro-fouling recruitment on natural fiber ropes was investigated in an IMTA-converted fish farm in the Mediterranean Sea. Over a 19-month cultivation cycle, a species-rich macrofouling assemblage was obtained, reaching a final biomass of 19-24 kg per rope, with only four species (S. spallanzanii, Mytilus galloprovincialis Lamarck, 1819, Phallusia mammillata (Cuvier, 1815), and Paraleucilla magna Klautau, Monteiro & Borojevic, 2004) contributing to 86 +/- 7 % of total biomass. Each species likely found favorable settlement conditions, exploiting available food resources and potentially helping to reduce/recycle excess organic matter. Despite high mortality, S. spallanzanii accounted for 66 +/- 7 % of final macrofouling biomass, with about 210,000 worms (ti1-ton live biomass) produced at IMTA farm scale using 196 10-m-long ropes. The observed decline in abundance during the cultivation cycle (from 3393 to 1090 individuals per rope) followed an exponential decay model, while individual growth (0.25-5.06 g) was described by a logistic curve, projecting the optimal harvest time between months 22-30, with a biomass peak of 1.57 +/- 0.85 tons. Chemical analyses showed elevated heavy metal concentrations in worm tubes and crowns, but body tissues remained below EU regulatory thresholds, supporting their safe use in fish feed. Additionally, due to their antimicrobial mucus and aesthetic features, worms show potential for both pharmaceutical and ornamental aquarium markets. These findings support S. spallanzanii as a valuable species for cultivation within IMTA systems, further highlighting the potential of macrofouling exploitation for integrated biomass valorization.

The new species Bispira causioi sp. nov. is here described. This taxon shares several morphological features, such as the shape of both uncini and companion chaetae, with other Bispira species mostly of tropical origin. The first observation of this taxon, along the Apulian coast, dates back to 2012 and was never recorded before. At the present, it occurs along the whole Italian Coasts, being reported in several pictures by the SCUBA-diving photographers and tentatively identified as either Sabella pavonina Savigny, 1822 or Bispira viola (Grube, 1863).In addition, in depth comparisons were conducted with material housed at the Museo di Biologia Marina of the Salento University, especially with the similar Mediterranean species (B. viola described by Grube 1863 deep muddy substrates), but also with material of tropical Bispira species present in this collection. An extensive discussion on the literature concerning the reports of B. viola in the past precede the new species description, suggesting different interpretations for our findings.

The influence of benthic suspension feeders as bioremediating organisms on water column seston and their ability to mitigate fish farm waste was assessed by monthly analyses for one year. A monthly monitoring from July 2020 to October 2021 of physico-chemical and biochemical variables of the water column and the sediment was performed in an in-shore mariculture plant located in the Mar Grande of Taranto (Italy), comparing two adjacent areas that differ in type of farming. The first (reference site) is a fish monoculture, while the second consists of an innovative Integrated Multi-Trophic Aquaculture system (IMTA site). The annual cycle of chlorophyll-a concentration showed values corresponding to mesotrophic/eutrophic conditions, with peak production in early fall (4.64 mu g L- 1). During the spring and summer sampling times, when the amount of aquaculture waste is greater than during the rest of the year, the reference site showed the highest lipid (151.73 mu g L- 1) and organic matter (189.00 mg g- 1) values with respect to those at the IMTA site. The IMTA bioremediating organisms possibly acted as underwater gardens changing the seston quality and availability and providing protection and food for the zooplankton community, which showed higher abundance of individuals for most sampling times at the IMTA site, peaking during September and October in both 2020 and 2021 (max 232,985.20 ind m- 3). Our results demonstrate the effectiveness of the considered IMTA system in mitigating the negative impact of organic matter release into the environment due to fish farming activities. The influence of bioremediating organisms on seston composition and concentration opened up mitigation as well as restoration scenarios.

Ocean acidification (OA) is considered a relevant additional threat to marine biodiversity and is linked to the increasing CO2 concentration in the atmosphere. Here, we provide a synthesis on the loss of both taxonomic and functional biodiversity, in the up to date best studied CO2 vents in the world, the Castello Aragonese of Ischia (Tyrrhenian Sea, Italy), analyzing a large data set available at this site and reporting qualitative taxonomic data along a gradient of OA from ambient normal conditions outside the vents (pH 8.1) to low pH conditions (pH 7.8–7.9) and extreme low pH conditions (pH < 7.4). A total of 618 taxa were recorded (micro- and macrophytes, benthic invertebrates, and fishes). A relevant loss of biodiversity (46% of the species) was documented from control/normal pH conditions to low pH, and up to 56% species loss from control of extreme low pH conditions. Functional groups analysis on the fauna (calcification, size, motility, feeding habit, and reproduction/development) allowed us to draw an identikit of the species which is able to better thrive under OA conditions. These are motile forms, small- or medium-sized, generalist feeders, at the low level of the food web (herbivores or detritivores), mainly brooders, or with indirect benthic development, and without calcification or weakly calcified.

The Indo-Pacific pearl oyster Pinctada radiata (Leach, 1814), a long established alien species in the Mediterranean Sea, has shown significant expansion in recent years, particularly in the Mar Grande of Taranto. This study assessed its potential as a sustainable aquaculture candidate in the context of Integrated Multi Trophic Aquaculture (IMTA). Specimens of P. radiata were cultivated for one year using coconut fiber collectors and monitored for growth, biochemical composition, chemical and microbiological safety. Results demonstrated rapid growth, with individuals reaching commercial size within one year. Biochemical analyses highlighted a favorable lipid profile, rich in polyunsaturated fatty acids (PUFAs), with a PUFA/SFA ratio of 0.93. Chemical and microbiological assays confirmed low contamination levels, complying with $\mathbf{E U}$ food safety standards. These findings indicate that, despite its invasive status, P. radiata could be valorized as a high-quality seafood product in warming Mediterranean environments, contributing to ecological resilience and economic diversification. A paradigm shift in alien species management, from exclusion to context-based evaluation, is therefore advocated.

The pearl oyster Pinctada radiata is considered among the 100 most invasive species in the Mediterranean Sea. Recently, a dramatic increase in P. radiata abundance has been recorded in the Mar Grande of Taranto (Ionian Sea) due to recurring heatwaves. This study investigated the structure and recruitment dynamics of P. radiata obtained in collectors made of plastic nets or coconut fibers within an Integrated Multi-Trophic Aquaculture (IMTA) system in the Mar Grande of Taranto. Furthermore, its nutritional value in terms of fatty acids and its chemical and microbiological quality were analysed in light of its potential commercial exploitation. The results revealed that the best growth performance was achieved with plastic nets. Reproduction occurred throughout the year with a peak in summer. The fatty acid profile of P. radiata at all sampling times revealed the predominance of PUFAs and SFAs over MUFAs. The pearl oyster was found to be a valuable source of omega-3 polyunsaturated fatty acids, as also evidenced by the high ∑ω3/ω6 ratios (range 2.81-4.51). Finally, the oyster quality was good from a microbiological and chemical point of view (PCB ICES-6 concentrations were below established European limits). In this scenario, the exploitation of this species is recommended for several reasons, including its decline in the area of origin and the creation of a market for human consumption and pearl production in the Mediterranean areas, where the species is finding an improved environmental situation due to global warming.

Sponges are benthic filter-feeder invertebrates capable to produce a variety of high value bioactive compounds. Nevertheless, exploitation of sponges as bio-factories requires scalable and sustainable strategies to supply sponge biomass without threatening wild natural populations and to minimize the consumption of toxic organic solvents in metabolites extraction and purification procedures. Sponges farming in integrated facilities nearby fish mariculture cages represents a highly efficient strategy combining the production of sponge biomass with bioremediation. Here we report the results of the in situ rearing of the keratose sponge Sarcotragus spinosulus developed within three years in an innovative Integrated Multi-Trophic Aquaculture system in the Gulf of Taranto (Southern Italy, Mediterranean Sea), capable to supply large-scale sponge biomass with a minimal impact on wild populations. Moreover, we demonstrate the proof of concept that it is possible to produce polyprenyl hydroquinones, selected as well-known bioactive model metabolites, in good yields, high purity degree and low organic solvent consumption, by means of an innovative protocol based on the combination of supercritical carbon dioxide fluid extraction and gel permeation chromatography. Such a combination of eco-friendly techniques paves the way to eco-sustainable supply of bioactive compounds from marine organisms highly profitable in terms of working times, costs, solvents, and energy saving.

This study investigated the flesh quality, shelf life, and sensory freshness of sea bream (Sparus aurata) reared in the REMEDIA Life IMTA system, which incorporates bioremediator organisms—sponges, polychaetes, bivalves, and macroalgae—supported by artificial vertical collectors to enhance the settlement of sessile macroinvertebrates and improve environmental quality. A total of 96 fish (18 months old) were analysed, 48 farmed within the IMTA system and 48 in the conventional offshore system. Both groups received the same commercial feed. For each group, 16 fish were analysed after 1, 7, and 14 days of storage at 2 ± 1 °C to evaluate physical features, chemical and fatty acid composition, and sensory freshness. The total weight was markedly greater for fish in the IMTA group (p < 0.05), which showed a significantly (p < 0.05) longer tail. For all the storage times, the content of total saturated fatty acids was markedly higher in the control group, along with a lower concentration of polyunsaturated fatty acids (p < 0.05). The quality index method showed better results for the IMTA group (p < 0.05), particularly after 2 weeks of storage in ice. In conclusion, sea bream reared in the IMTA system showed better flesh quality, extended shelf life, and prolonged sensory freshness.

This study investigates the effects on hard-bottom macro-zoobenthic communities of converting a mariculture plant into an Integrated Multi-Trophic Aquaculture (IMTA) system. This study was conducted from 2018 to 2021 in the semi-enclosed Mar Grande basin of Taranto (northern Ionian Sea), on a facility located 600 m off the coastline, with a production capacity of 100 tons per year of seabass (Dicentrarchus labrax) and seabream (Sparus aurata). The results from seasonal sampling performed in a treatment site, where bioremediators (filter-feeding invertebrates such as sponges, polychaetes, mussels, and macroalgae) were deployed, and a control site without bioremediators were compared. Before the IMTA installation, the hard substrates under the cages were sparsely inhabited, with significant sediment coverage. By 2021, the treatment site exhibited revitalized and more diverse macro-zoobenthic communities, with species richness increasing from 83 taxa in 2018 to 104 taxa, including notable growth in sponges, annelids, mollusks, and bryozoans. In contrast, the control site showed no substantial changes in biodiversity over the same period. Biodiversity indices, including Shannon and Margalef indices, improved significantly at the treatment site, particularly during summer months, highlighting a more resilient and balanced benthic environment. Taxonomic distinctness (delta+) and multivariate analyses (PERMANOVA, PCO) confirmed significant spatial and temporal shifts in community structure at the treatment site, driven by IMTA implementation. SIMPER analysis identified key taxa contributing to these changes, which played a pivotal role in structuring the community. The emergence of filter feeders, predators, and omnivores at the treatment site suggests enhanced nutrient cycling and trophic complexity, while the decline in opportunistic species further supports improved environmental conditions. These findings demonstrate the potential of IMTA to promote recovery and sustainable mariculture practices, also offering a comprehensive understanding of its positive effects on hard-bottom benthic community dynamics.

Short-time cycles of the water column can reflect undetectable changes in seasonal cycles, providing a high temporal resolution for quantifying seston availability. Here, trends in seston quantity and quality were investigated through intensive temporal cycle assessments at an IMTA site and a nearby fish farm facility (control site) during two different periods of the year (July 2021 and March 2022).Chlorophyll-a values (max 10.28 mu g L- 1) showed no significant differences between sites, while lipid values (max 394.87 mu g L- 1) were significantly lower at the IMTA site than at the control site during most sampling times, suggesting that the bioremediating organisms at the IMTA site may help mitigate the impact of fish farming. The IMTA site structured a marine animal forest capable of increasing the abundance of zooplankton, reaching 109,021 ind m- 3. The short-time cycle appeared useful for detecting changes that occur at high temporal resolution, underlying the effects of mitigation measures behind the high variability of marine coastal systems.

European aquaculture mussel production of the species Mytilus galloprovincialis is in decline and this also concerns Italy with a long tradition in Taranto. This decrease can be due to multiple stresses linked to climate change. Here, to overcome the high summer temperatures of the Mar Grande of Taranto, the growth performance and mortality of mussels were compared, during a production cycle, in different farming conditions: i) inside and outside an integrated multitrophic aquaculture system, where some bioremediators were placed around cages with the fish species Sparus aurata, and ii) at two different depths, (0-4 m) and (8-12 m). Biochemical, microbiological and chemical analyses were performed on the final product. Mussel growth performances were significantly different only in relation to the depth. Due to the high temperatures recorded in July (max. 31.01 °C at the surface) the reared mussels did not reach the requested condition index for the marketing. Moreover, mussels reared on the surface resulted more vulnerable to air exposure. Mussel's nutritional and chemical values, reported as lipid and protein content, fatty acids profile, Polycyclic Aromatic Hydrocarbons (PAHs) and Polychlorinated Biphenyls (PCBs) concentrations, showed that proximity to the mariculture plant and greater depths, did not influence the overall good quality of the product. Moreover, mussels resulted safe from a microbiological point of view. Considering that extreme temperatures will likely intensify in the future, further efforts are needed to design new farming strategies, such as an IMTA system in an offshore wind farm, to overcome this challenge.

Integrated Multi-Trophic Aquaculture (IMTA) has emerged as a promising solution to reduce and recycle the excess inorganic/organic matter from fed species farming through the inclusion of extractive species such as algae and suspension/deposit feeders Ascidians, being highly efficient suspension feeders, show strong potential for use in IMTA systems, contributing to converting fish waste into valuable biomass. This study evaluated the growth performance and biomass yield of the ascidians Phallusia mammillata (Cuvier, 1815) and Styela plicata (Lesueur, 1823) cultured in a Mediterranean IMTA system using natural fiber ropes as settlement substrates. Ropes were deployed in November 2022, and monitoring occurred monthly from May to October 2023. Cohorts were identified through size-class analysis and modal progression, allowing estimation of monthly growth rates. Phallusia mammillata exhibited consistent growth, reaching 9.34 $\pm 1.34 \mathrm{~cm}$ in October with an average increase of $1.27 \mathrm{~cm} / \mathrm{month}$. Styela plicata showed higher recruitment rates and densities peaking in June at $686 \pm 87$ individuals per rope, with a growth rate of $0.79 \mathrm{~cm} /$ month. Through allometric relationships, live weight was derived to estimate ascidian biomass production. Maximum biomass per rope reached $0.60 \pm 0.16 \mathrm{~kg}$ for P. mammillata and $1.32 \pm 0.21 \mathrm{~kg}$ for S. plicata over 4-6 months of cultivation, corresponding approximately to 400 kg of ascidians at the IMTA facility scale ($118 \pm 33 \mathrm{~kg}$ for P. mammillata and $259 \pm 42 \mathrm{~kg}$ for S. plicata). These results support the feasibility of incorporating ascidians into IMTA systems, highlighting their bioremediation potential, ease of cultivation, fast growth, and valuable biomass production for various biotechnological applications.

Microplastics (MPs) are insidious plastic particles with sizes ranging from 1 to 5000 µm. Their presence has been reported all over the world. Recently, bioremediation to remove MPs from water columns using filter feeders as biofilters has been proposed. In a previous lab experiment, the MP bioremediation potential of four fouling organisms from a mariculture facility (Mytilus galloprovincialis, Sabella spallanzanii, Phallusia mammillata, Paraleucilla magna) was separately assessed in single-species experiment. Herein, a follow-up of the work is presented using a multi-species approach. The four organisms were placed together in the same 5 L beaker and fed with a concentration of 250 p/L 6 µm red polystyrene discernible particles. After digesting the organisms and counting the MPs in both the water and the organisms, the results of the two experiments were compared. In the previous experiment, S. spallanzanii had the highest particle retention (PR) value (PR = 88.01%), while in this experiment, P. mammillata has the lowest PR value (PR = 31%). The multi-species approach resulted in a higher number of plastics being removed from the water (88%) compared to the single-species experiments. These fouling organisms naturally exist as a community, acting as an efficient filter with complex morphologies and hydrodynamic features. Here, this simple marine animal forest is re-evaluated by exploiting the ecosystem services provided by these organisms as a solution to MP pollution problem in a mariculture environment.

Marine bioconstructions are complex habitats that represent a hotspot of biodiversity. Among Mediterranean bioconstructions, those thriving on mesophotic bottoms on southeastern Italian coasts are of particular interest due to their horizontal and vertical extension. In general, the communities that develop in the Mediterranean twilight zone encompassed within the first 30 m of depth are better known, while relatively few data are available on those at greater depths. By further investigating the diversity and structure of mesophotic bioconstructions in the southern Adriatic, we can improve our understanding of Mediterranean biodiversity while developing effective conservation strategies to preserve these habitats of particular interest. The dataset reported here comprises records of benthic marine taxa from algae and invertebrate mesophotic bioconstructions investigated at six sites along the southern Adriatic coast of Italy, at depths between approximately 25 and 65 m. The dataset contains a total of 1718 records, covering 11 phyla and 648 benthic taxa, of which 580 were recognized at the species level. These data could provide a reference point for further investigations with descriptive or management purposes, including the possible assessment of mesophotic bioconstructions as refuges for shallow-water species.

In recent years, population outbreaks of the annelid Hermodice carunculata (Polychaeta, Amphinomidae) are recurrently detected along the coastal zone of the Salento peninsula (Southern Italy), with impacts on marine benthic ecosystems. Annelida are renowned for their remarkable regeneration potential, enabling them to reform lost body parts by asexual reproduction processes. A handful of studies have reported posterior regeneration of H. carunculata, but anterior regeneration and asexual reproduction have not been fully explored. In this study, we investigated the capacity of H. carunculata collected in shallow coastal areas (Ionian Sea, 40°08'26.9" N 17°58'44.1" E) to regenerate anterior body parts under different temperature conditions (22 and 14°C) and considering two different body sizes (~ 4 g and 25 g). In addition, histological analysis and lipid analyses were carried out to detect changes in the reproductive cycle and lipid storage during ongoing regeneration. The results suggest that small and large-sized specimens of H. carunculata can regenerate efficiently anterior body parts in 12–20 weeks post amputation (wpa) when kept at 22°C. Small-sized worms kept at 14°C regenerated slower but died in 24wpa before regenerating a mouth, while large-sized worms kept at 14°C were affected by a 100% mortality during blastema formation. In addition, lipid extraction analyses show that H. carunculata can regenerate during extended periods of starvation by de novo synthesizing lipid reserves and regeneration in H. carunculata does not negatively impact the reproductive cycle, as gametogenesis occurs also during the regenerative processes.

The Salento Peninsula represents the eastern-most edge of the Italian Peninsula, and one of the first areas to be invaded by thermophilic non-indigenous species. The diversity of non-indigenous polychaetes occurring along the Salento Peninsula is reviewed based on literature data and new samples. Overall, fifteen non-indigenous polychaetes were recorded; among them, Syllis similisunzima is reported for the first time in the Mediterranean Sea; Lepidonotus tenuisetosus is recorded for the first time in Italian waters; Pseudonereis anomala, until now known only for Sicily, is reported for the first time from the Italian Peninsula; Dorvillea similis is a first record for the Ionian and Adriatic Sea. 16S rDNA and COI sequences were obtained for eleven species, allowing us in some cases to confirm their identity and/or geographical origin, while in the case of some species they represent the first molecular data ever obtained.