Search

A specimen of a sixgill bluntnose shark, Hexanchus griseus (Bonnaterre, 1788), was caught 1.5 NM north of Cape Ronek (Izola, Slovenia) in a fishing net for large-sized flatfish (such as turbot) on 28 January 2018. Three other older cases of catch of sixgill bluntnose sharks were recorded in Slovenia and the Gulf of Trieste. Among these, the finding of the specimen in the Lagoon of Marano and Grado is unusual although there are reported cases of sixgill bluntnose sharks in rivers. An analysis of the available data on the bluntnose sixgill shark in the Adriatic Sea, obtained from different published papers, social media and other sources, was done to understand whether the occurrence of H. griseus in the northern Adriatic differs from other parts. A generalised linear model (GLM) approach revealed that larger specimens are more frequently sighted across the Adriatic Sea, while in the Northern Adriatic part, significantly smaller specimens (juveniles) were recorded in comparison to the Central and Southern parts. It seems that the bluntnose sixgill shark is not in conjunction with a common large shark decreasing trend across the whole Mediterranean Sea.

To enrich spatio-temporal information on the distribution of alien, cryptogenic, and neonative species in the Mediterranean and the Black Sea, a collective effort by 173 marine scientists was made to provide unpublished records and make them open access to the scientific community. Through this effort, we collected and harmonized a dataset of 12, 649 records. It includes 247 taxa, of which 217 are Animalia, 25 Plantae and 5 Chromista, from 23 countries surrounding the Mediterranean and the Black Sea. Chordata was the most abundant taxonomic group, followed by Arthropoda, Mollusca, and Annelida. In terms of species records, Siganus luridus, Siganus rivulatus, Saurida lessepsianus, Pterois miles, Upeneus moluccensis, Charybdis (Archias) longicollis, and Caulerpa cylindracea were the most numerous. The temporal distribution of the records ranges from 1973 to 2022, with 44% of the records in 2020–2021. Lethrinus borbonicus is reported for the first time in the Mediterranean Sea, while Pomatoschistus quagga, Caulerpa cylindracea, Grateloupia turuturu, and Misophria pallida are first records for the Black Sea ; Kapraunia schneideri is recorded for the second time in the Mediterranean and for the first time in Israel ; Prionospio depauperata and Pseudonereis anomala are reported for the first time from the Sea of Marmara. Many first country records are also included, namely: Amathia verticillata (Montenegro), Ampithoe valida (Italy), Antithamnion amphigeneum (Greece), Clavelina oblonga (Tunisia and Slovenia), Dendostrea cf. folium (Syria), Epinephelus fasciatus (Tunisia), Ganonema farinosum (Montenegro), Macrorhynchia philippina (Tunisia), Marenzelleria neglecta (Romania), Paratapes textilis (Tunisia), and Botrylloides diegensis (Tunisia).

This Collective Article presents information on 20 taxa belonging to five (5) Phyla: Cnidaria (2), Mollusca (8), Arthropoda (4), Echinodermata (1) and Chordata (5) recorded from the Alboran Sea to the Levantine Sea. These new records were found in seven (7) different ecoregions as follows: Alboran Sea: new record of the rare football octopus Ocythoe tuberculata in the harbour of Algeciras (Spain) ; Western Mediterranean Sea: first record of the isopod Arcturinella deltensis in the Ligurian Sea, and the third 969Medit. Mar. Sci., 23/4 2022, 968-994in the whole Mediterranean Sea ; third Mediterranean site for the MuricidaeCoralliophila ahuiri along the Italian coasts (Alghe-ro) ; first and westernmost record of the goby Corcyrogobius liechtensteini from the Iberian Peninsula ; new record of the sea slug Glaucus atlanticus from the coast of the Iberian Peninsula ; first and easternmost record of Holothuria (Vaneyothuria) lentiginosa lentiginosa along the Italian coasts ; Tunisian Plateau/Gulf of Sidra: seventh record of the oceanic squid Thysanoteuthis rhombusin Tunisia, and first for the Gulf of Gabes. Ionian Sea: second occurrence of the Atlantic tripletail Lobotes surinamensis in the Ionian Sea and first record from the Strait of Messina area ; new record of the rare sea elephant Pterotrachea coronata from the Strait of Messina ; Adriatic Sea: first record of a facies of football ascidian Diazona violacea in the South Adriatic Sea (Tremiti Island, Italy) ; two records of the sevengill shark Heptranchias perlo in Croatian waters after more than 70 years of absence of documented records in this area ; first known occurrence of the nudibranch Jalonus hyalinus in Slovenian waters and also the first known occurrence of this species in the Adriatic Sea ; first record of the nudibranch Okenia elegans in Slovenian waters ; Aegean Sea: First record of the parasitic isopod Nerocila milesensis along Greek coasts (Crete island) as well as the second record world-wide ; additional record of the brachyuran Paragalene longicrura collected from the Saronikos Gulf (Greece) ; first record of the siphonophore Rhizophysa filiformis in Greek waters as well as the second record of this species in the eastern Mediterranean basin ; new record of the rare and protected angelshark Squatina aculeata along Turkish coasts ; Levantine Sea: first record of the marine amphipod Caprella andreae in the Levantine Mediterranean shore of Israel, based on both morphological and molecular data ; first occurrence of the cephalopod Tremoctopus violaceus along Turkish coasts, which confirms its presence in the north-eastern coasts of Turkey ; record of a bloom of the thermophilic jellyfish Pelagia noctiluca in the north Levantine Sea.

An updated and evidence-based checklist of Mediterranean Sea fishes is provided. Each of the fish species in the Mediterranean Sea listed here was either listed in the last published checklist of the Mediterranean fishes or in other articles, reports or new records, and the checklist is critically assessed. Out of the assessed 791 species previously reported from the Mediterranean, the presence of 759 species is confirmed while 32 species are excluded from the new checklist, by lacking evidence of presence or representing obvious taxonomic confusions. The net increase in known Mediterranean fish species richness since the last checklist is 11%. The non-native Mediterranean species now represent 22.1% (168 species) of the known Mediterranean fish diversity. The evidence-based protocol applied here provides a reliable checklist of marine fishes, for which each of the included species has indeed been recorded at least once within the discussed geographic area in the Mediterranean Sea.

V zadnjih desetletjih smo priča postopnemu izginjanju morskih travnikov na globalnem nivoju, pri čemer naj bi se njihova površina skrčila za tretjino. Tudi v slovenskem delu Jadrana prihaja do krčenja morskih travnikov, glavne vzroke za to moramo pripisati dejavnikom, kot so plovne poti in pristaniške dejavnosti, poglabljanje morskega dna, komercialne in rekreacijske dejavnosti, kot sta ribolov in privezovanje, odtekanje vode z urbanih in kmetijskih območij, v zadnjem času tudi vse intenzivnejše podnebne spremembe in kisanje oceanov. V pričujoči publikaciji predstavljamo rezultate kartiranja morskih travnikov v Krajinskem parku Strunjan, kjer je bilo v zadnjih letih, zlasti od leta 2018, opaženo obsežno upadanje. Ob tem razpravljamo o dejavnikih, ki vplivajo na razširjenost in regresijo morskih travnikov. Uporaba digitalnih ortofoto posnetkov in satelitskih podob (daljinsko zaznavanje) sta se izkazali za obetavni metodi, ki sta omogočili ugotavljanje prostorskih sprememb v času. Na predelih notranjega dela Strunjanskega zaliva so se travniki kolenčaste cimodoceje (Cymodocea nodosa) skrčili za več kot 80 % površine iz leta 2017. Upoštevaje pokrovnost morskih travnikov v celotnem slovenskem morju se je ta v letih od 2017 do 2018 zmanjšala za približno dobro petino.

Podatki 6. poročila IPCC nakazujejo še intenzivnejši trend dviga morske gladine v drugi polovici stoletja. Piranski zaliv bi lahko bil v primeru uresničitve pesimističnih napovedi (ssp585) izpostavljen dvigu morske gladine tudi za 120 cm (v primerjavi z obdobjem 1995–2014). Nedvomno bodo zaradi tega prizadeta nizko ležeča obalna mokrišča in nanje vezani organizmi. Obrežne ptice (še posebej gnezdilke) bodo, zaradi visokega položaja v prehranjevalnem spletu obmorskih mokrišč, prvi pokazatelj okoljskih sprememb. V raziskavi obravnavamo odziv štirih vrst obrežnih ptic, kot so polojnik (Himantopus himantopus), beločeli deževnik (Charadrius alexandrinus), navadna (Sterna hirundo) in mala čigra (Sternula albifrons), na dvosmerni okoljski pritisk (dvig morske gladine in širjenje antropogenih dejavnosti) v Krajinskem parku Sečoveljske soline (KPSS). Oceno potencialne spremembe gnezditvene površine ptic zaradi dviga morske gladine smo izračunali na podlagi modelov razširjenosti vrst (Mahalanobisova tipičnost in Maxent). Ugotovitve kažejo, da se bosta beločeli deževnik in polojnik v KPSS kmalu soočila z zmanjšanjem potencialne gnezditvene površine, medtem ko so napovedi za obe vrsti čiger manj dramatične. Odkrit individualistični odzivi preučevanih vrst ptic na dvig morske gladine kot posledice podnebnih sprememb je lahko pomembna informacija za varstvene biologe v zavarovanih območjih, ki pripravljajo načrte za ublažitev negativnih vplivov na zavarovane habitate.

Heterobranch molluscs fauna in Montenegro has been poorly investigated so far. The aim of the present paper is to improve the knowledge about species diversity of these marine organisms in the Boka Kotorska Bay, a specific fjord-like entity in the southern Adriatic Sea. New records of seven heterobranch species were obtained by field surveys in 2017, while three new records were provided by analysing underwater photographs from previous periods. The resulted checklist summarizes the knowledge of the diversity of heterobranchs in the Boka Kotorska Bay from the oldest record in 1967 to the present day and consists of a total of 62 heterobranch species., Fauna puževa golaća (Heterobranchia) u Crnoj Gori je do sada slabo istražena. Cilj ovog rada je bio unaprijediti saznanja o ovim morskim organizmima u zalivu Boka Kotorska, specifičnom, nalik fjordu zalivu južnog Jadrana. Novi nalazi za sedam vrsta heterobranchia su pronađeni tijekom naših terenskih istraživanja u 2017. godini, dok su podaci za tri nova nalaza dobijeni analizom podvodnih fotografija iz prethodnih razdoblja. Ažurirana lista sumira saznanja o raznolikosti puževa golaća u Bokokotorskom zalijevu od najs-tarijeg zapisa iz 1967.g. do danas, a obuhvaća ukupno 62 vrste.

Cryptobenthic fishes were often overlooked in the past due to their cryptic lifestyle, so knowledge of their ecology is still incomplete. One of the most poorly studied taxa of fishes in the Mediterranean Sea is clingfish. In this paper we examine the habitat preferences of three clingfish species (Lepadogaster lepadogaster, L. candolii, and Apletodon incognitus) occurring in the Gulf of Trieste (Northern Adriatic). The results show that all three species have a cryptic lifestyle and are well-segregated based on their depth distribution and macro- and microhabitat preferences. L. lepadogaster inhabits shallow waters of the lower mediolittoral and upper infralittoral, where it occurs on rocky bottoms under stones. L. candolii similarly occurs in the rocky infralittoral under stones, but below the lower distribution limit of L. lepadogaster, and in seagrass meadows, where it occupies empty seashells. Such hiding places in seagrass meadows are also occupied by A. incognitus, which mostly occurs below the lower distribution limit of L. candolii. Despite the overlap of depth and macrohabitat, the probability of individuals of two species encountering each other or competing in the same habitat is low when the depth range is combined with the microhabitat preferences of these species.

The zooplankton community was analyzed in ten Adriatic ports as part of the port biological baseline surveys carried out within the framework of the BALMAS project. We provide the first inventory of resident zooplankton taxa and five detected non-indigenous zooplankton species (NIS), and their spatial and seasonal distribution patterns. Copepoda and meroplankton larvae, particularly of Mollusca, dominated the zooplankton in all sampled ports. We recorded a total of 76 indigenous copepod species and five NIS, among which Parvocalanus crassirostris detected in Šibenik and Rijeka ports and Oithona davisae in Venice port, are new for the Adriatic. All detected NIS were widely distributed within the recipient ports. Co-occurrences of NIS were observed in the ports of Venice, Bari, Ancona and Trieste. The results are expected to contribute to the quality of practical monitoring of zooplankton NIS and facilitate the synchronization of efforts in creating NIS- related policies for the Adriatic sub-region.

The Adriatic Sea is considered as a hotspot of marine biodiversity but, due to intense human activities (e.g. maritime transport, mariculture), it is also a recipient area of non-indigenous species (NIS). This study analyzed the scientific literature on non-indigenous macrophytes (NIM) recorded in ports, marinas and transitional waters (TWs) of the Adriatic Sea, in the period 1987–2018. The results show that 51 out of 118 Mediterranean NIM are found in Adriatic ports and TWs. The Venice Lagoon is the main Adriatic recipient area of NIM. Mariculture is the main vector of introduction, whereas the principal pathways of NIM dispersal are shipping and shellfish transfer. The largest group of NIM is of temperate northern Pacific origin. This study corroborated the fact that ports and TWs act as dispersal hubs and invasion hotspots. The importance of early detection of NIM at such sites should be considered in any environmental management strategy.

The Mediterranean stony coral Cladocora caespitosa (Linnaeus, 1767) is a well-known habitat builder, and as such hosts a diversified faunal assemblage. Although polychaetes are one of the most abundant and diverse macrobenthic groups associated with C. caespitosa colonies, our knowledge of their ecological features in this association is still limited. The aim of this paper was to gather and compare the most comprehensive data available on polychaetes associated with C. caespitosa in the Adriatic and the Aegean Seas, and to test for differences between these geographic areas. To this end, differences were tested in terms of: (i) richness and structure of polychaete assemblages; (ii) feeding and functional traits of assemblages; (iii) the main factors influencing those aspects, (iv) the relationship between polychaete assemblages richness and Cladocora colony size, and estimate richness. Differences were observed between the Adriatic and the Aegean Seas, in terms of richness, species composition and relative proportion of the dominant feeding guild (filter feeders most abundant in the Aegean and carnivores in the Adriatic) and motility mode (sessile most abundant in the Aegean and motile in the Adriatic). Conversely, cosmopolitan and Atlanto-Mediterranean species dominated the assemblages in both geographic areas, and the same Species-Area Relation model proved to be effective for richness estimation in both geographic areas.

We investigated the concentration and composition of plastics in 7 Special Areas of Conservation (SACs) from the Gulf of Venice (northern Adriatic Sea). A total of 42 sediment samples were analyzed from 21 sites from 2017 to 2018. All sites except one were found to be polluted by plastics, with density ranging between 2250 and 28.4 items kg−1. Microplastics ranged from 100 to 61.6% of the collected plastics. Fragments were more represented than filaments. The greatest plastic concentrations were generally recorded in western SACs. Identification through FT-IR spectroscopy evidenced the presence of 8 polymer types: in western SACS, the majority were low-density polymers (PE, PP, PS, and TPU), while in eastern SACs they were high-density polymers (PET, nylon, and PVC). In addition to the role of large rivers (all on the western side of the Gulf) in conveying plastics into the sea, a possible role of the cyclonic water circulation of the northern Adriatic Sea on distribution and composition of plastics along the Gulf coasts is likely.

Non-indigenous species are confirmed to be among the biggest threats for marine biodiversity. Among them, non-indigenous macrophytes (NIM) are well known to have local negative effects, especially in coastal ecosystems. Since transitional waters (TWs), ports and also marinas are recognized as very vulnerable coastal ecosystems, greatly subjected to biological invasions, the present study analysed the available scientific literature on NIM in such areas in the Central Mediterranean Sea (CMED), in the period 1970-2019. The analysis underlined that 27 NIM were recorded in CMED TWs, marinas and ports. Around 37% of them (10 species) are marked as invasive, while about 11% (3 species) are considered as potentially invasive. Maricultural activities resulted the key vector of introduction, while the primary pathway of NIM dispersion is related to maritime activities. The paper also discusses why in CMED TWs, marinas and ports, currently, less NIM were detected than in similar Adriatic areas.

The updated checklist of Adriatic Sea fishes with a critical assessment of each species using an evidence approach is provided. Each fish species in Adriatic Sea listed in the last published checklist and those reported in published new records not included in the most recent Adriatic checklist, have been included. Of the total of 466 fish species, the presence in the Adriatic Sea was confirmed for 444 species by at least one positive record of the species in the area, the presence of 10 species is still unconfirmed, and 12 fish species are excluded from the list. An evidence approach protocol is recommended for general use for compiling checklists of marine fishes.

On 3rd June 2018 three juvenile specimens of Polyprion americanus were captured in the Gulf of Trieste. The wreckfish is a long-lived deep-water demersal species characterized by an extended pelagic juvenile phase. The juvenile forms are recurrently recorded in the northern Adriatic and due to data deficiency for this species, original morphometric data are shown. The occurrence of P. americanus in the Gulf of Trieste is not a typical case of thermophilic species moving northward due to Mediterranean tropicalization, rather its recurrent appearance could be investigated for specific hydrological conditions coupled to its peculiar life span., Dana 3. lipnja 2018. u Tršćanskom zaljevu ulovljena su tri jedinke mlađi kirnje glavulje Polyprion americanus. Kirnja glavulja je dugovječna vrsta duboke vode, koju karakterizira produljena pelagična faza mlađi. Jedinke mlađi opetovano se bilježe u sjevernom Jadranu, a zbog nedostatka podataka za ovu vrstu, prikazani su izvorni morfometrijski podaci. Pojava P. americanus u Tršćanskom zaljevu nije tipičan slučaj termofilnih vrsta koje se kreću prema sjeveru zbog mediteranske tropikalizacije, već bi se njihov ponovljeni nalaz mogao istražiti u specifičnim hidrološkim uvjetima zajedno s osebujnim životnim vijekom ove vrste.

Este artículo contiene 18 páginas, 4 figuras., Good datasets of geo-referenced records of alien species are a prerequisite for assessing the spatio-temporal dynamics of biological invasions, their invasive potential, and the magnitude of their impacts. However, with the exception of first records on a country level or wider regions, observations of species presence tend to remain unpublished, buried in scattered repositories or in the personal databases of experts. Through an initiative to collect, harmonize and make such unpublished data for marine alien and cryptogenic species in the Mediterranean Sea available, a large dataset comprising 5376 records was created. It includes records of 239 alien or cryptogenic taxa (192 Animalia, 24 Plantae, 23 Chromista) from 19 countries surrounding the Mediterranean Sea. In terms of records, the most reported Phyla in descending order were Chordata, Mollusca, Chlorophyta, Arthropoda, and Rhodophyta. The most recorded species was Caulerpa cylindracea, followed by Siganus luridus, Magallana sp. (cf. gigas or angulata) and Pterois miles. The dataset includes records from 1972 to 2020, with the highest number of records observed in 2018. Among the records of the dataset, Dictyota acutiloba is a first record for the Mediterranean Sea. Nine first country records are also included: the alga Caulerpa taxifolia var. distichophylla, the cube boxfish Ostracion cubicus, and the cleaner shrimp Urocaridella pulchella from Israel; the sponge Paraleucilla magna from Libya and Slovenia; the lumpfish Cyclopterus lumpus from Cyprus; the bryozoan Celleporaria vermiformis and the polychaetes Prionospio depauperata and Notomastus aberans from Malta., The publication of this article is supported by the Open Access Publishing Fund of the International Association for Open Knowledge on Invasive Alien Species (INVASIVESNET; www.invasivesnet.org). Stelios Katsanevakis, Maria Sini and Konstantinos Tsirintanis were supported by the Hellenic Foundation for Research and Innovation (H.F.R.I.) under the “First Call for H.F.R.I. Research Projects to support Faculty members and Researchers and the procurement of high-cost research equipment grant” (Project Number: HFRI-FM17-1597). Enalia Physis acknowledges Pantelis Patsalou for his support with field-logistics and links with fishers. Fiona Tomas would like to acknowledge funding from FECYT FCT- 14-9319 (¡OJO A LAS INVASORAS! BIODIVERSIDAD Y ESPECIES INVASORAS DEL MEDITERRÁNEO BALEAR). Vasilis Gerovasileiou, Thanos Dailianis and Maria Sini acknowledge the support by the MARISCA project (www.marisca.eu), co-funded (85%) by EEA GRANTS, 2009–2014, and the Public Investments Program (PIP) of the Hellenic Republic (15%). Razy Hoffman acknowledges funding by Yad-Hanadiv foundation, through the Israel Society of Ecology and Environmental Sciences and Israel Nature and Parks Authority (An integrated program for establishing biological baselines and monitoring protocols for marine reserves in the Israeli Mediterranean Sea). Argyro Zenetos and Paraskevi K. Karachle would like to thank the citizenscientists collaborating with the Ellenic Network on Aquatic Invasive Species (ELNAIS – elnais.hcmr.gr). Nikolaos Doumpas, Ioannis Giovos, Periklis Kleirou and Francesco Tiralongo would like to thank all the citizen-scientists that contributed with their shared records and data in the citizen-science project “Is it alien to you? Share it!!!” (https://www.facebook.com/ groups/104915386661854/). Data from Gyaros Island marine reserve were collected under the “GyarosMPA” project, funded by “MAVA Fondation pour la Nature”. Data from Corsica coastline were mainly collected in the framework of the “Corsica Alien Network” initiated by “Office de l’Environnement de la Corse”. Carla Morri and Carlo Nike Bianchi received financial support from FFARB (funds for basic research activities) by the Italian Ministry of Education, University and Research. Ergün Taşkın has been supported by TÜBİTAK, Ankara, Turkey (Project Number: 114Y238). The Slovenian authors would like to acknowledge their financial support from the Slovenian Research Agency (research core funding No. P1-0237) and the Ministry of Agriculture, Forestry and Food of the Republic of Slovenia. Mehmet Fatih Huseyinoglu thanks University of Kyrenia’s Scientific Research Project numbered GRN-20191-004. Fabio Crocetta was funded by the COST (European Cooperation in Science and Technology) Action TD1209 Alien Challenge project. The FRI (HAO DEMETER) team is very grateful to the Marine Strategy Project for financial support. Records of NIS in Jbel Moussa, the National Park of Al Hoceima and Cap des Trois Fourches sites from Morocco were obtained during surveys conducted within the framework of the MedKeyHabitats and the MedMPAnet Projects implemented by UNEP/MAP-RAC/SPA in close collaboration with the Haut Commissariat aux Eaux et Forêts et à la Lutte Contre la Désertification (HCEFLCD) and financially supported by RAC/SPA, Tunisia and the MAVA Foundation, Switzerland (MedKeyHabitats Project) and the European Commission (EC), the Spanish Agency for International Cooperation to Development (AECID), and the French Global Environment Facility (MedMPAnet Project). Jamila Ben Souissi was partially funded by BiodivMex /Chantier MISTRALS. Konstantinos Tsiamis sampling records were retrieved during his post in the Hellenic Centre for Marine Research, which he would like to thank for. Periklis Kleitou and Demetris Kletou were supported by the LIFE financial instrument of the European Union – RELIONMED project [Grant Agreement LIFE16 NAT/ CY/000832]. Some of the data included in the dataset were obtained through the marine citizen science platform Observadores del Mar www.observadoresdelmar.es with the support of FECYT FCT-17-12469, LIFE IP Intemares and Fundació Marilles, and through the citizen science site of the Italian Marine Protected Area of “Regno di Nettuno” (islands of Ischia, Procida and Vivara): www.citizensciencerdn.org. Most data from Lebanon were retrieved from social media dedicated to citizen science (Facebook group: Sea Lebanon https://www.facebook.com/ groups/109615625861815/) or fishers and scuba divers WhatsApp groups). Jamila Rizgalla wishes to thank the administration of Regatta for granting a free pass to conduct field surveys and the security personnel for providing a safe environment. Anna Occhipinti-Ambrogi was supported by European Community’s Seventh Framework Program VECTORS (Vectors of Change in Oceans and Seas Marine Life, Impact on Economic Sectors). The long lasting collaboration with the ICES Working Group on Introductions and Transfer of Marine Organisms (WGITMO) has been a good forum where many information and ideas could be exchanged within some of the authors (Anna Occhipinti-Ambrogi, Argyro Zenetos, Agnese Marchini, and a wider community of scientists working on biological invasions). A. Rosso and R. Sanfilippo received grants from the Catania University Research Plan 2016/2018. Data from Kuriat island were collected under the “Kuriat project”, funded by “MAVA Fondation pour la Nature” executed by SPA/RAC in partnership with the Coastal Protection and Management Agency (APAL) and Notre Grand Bleu (NGB) NGO. The AIS/ERA (Environment and Resources Authority) Maltese data were obtained from the EU funded project EMFF 8.3.1 under the European Maritime and Fisheries Fund 2014–2020 with a total cost of €1.6 million in public eligible EMFF funds (75% EU 25% MT), managed by AIS/ERA (Environment and Resources Authority). The ultimate goals of this European Maritime and Fisheries Fund (EMFF 2014–2020) project are to devise a holistic approach towards marine monitoring and develop a comprehensive database of data collected about the Maltese waters., With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

One specimen belonging to the nudibranch Marionia blainvillea (Risso, 1818) was found crawling on the gorgonian Leptogorgia sarmentosa (Esper, 1789) at Sv. Nedjelja, Boka Kotorska Bay, Montenegro. This is the first record of the species for Montenegrin waters and the third for the Adriatic Sea.

Cladocora caespitosa is an endemic coral of the Mediterranean Sea and an important carbonate bioconstructor that adds 3D complexity to the habitat, thus increasing marine biodiversity. Despite its important role in the ecosystem, the real status of the population along most of the Mediterranean coastline is still poorly investigated and very little is known about the resilience of the species. Using non-destructive visual surveys, colonies of C. caespitosa were investigated by SCUBA diving in 2013 and 2015 at seven sites of the northern Adriatic Sea (southern part of the Gulf of Trieste). Data about colony size, index of sphericity and corallite diameter were collected. Almost all biometrical parameters differed significantly among sampling sites, showing low occurrence of the larger size classes compared to the abundance of small-sized colonies. This pattern of distribution is typical of long- lived organisms. The positively skewed colony size distribution could be due to both a high mortality rate of small colonies unable to reach larger size classes, and to a high fragmentation rate of colonies, related to a strong hydrodynamic forces. The northern Adriatic population of C. caespitosa has previously been investigated by Schiller, who reported size and abundance data of colonies from one site, at a depth range of 2–5 m. We compared these data with our findings from the same sampling site, adding new information about the ecology of C. caespitosa. After a 30-year period, the comparison shows a change in the size distribution of colonies, with a decrease of the small class and an increase of the medium class of colonies. In view of these conclusions, further assessments are required in order to evaluate the trend of the northernmost C. caespitosa population in the Mediterranean Sea.

We studied seasonal abundance, vertical distribution and life history traits of the Mediterranean mud shrimp (Upogebia pusilla) in the mediolittoral zone in Slovenia. At two localities (Strunjan and Lazaret), quantitative samples from three plots (1 m2 each) at (0 cm), below (-50 cm) and above (+50 cm) mean water level were taken once every two months, in alternation. A set of parameters was also recorded, including vegetation cover, sediment type, air and sea temperature, pH, salinity and oxygen levels. Highest abundance was recorded during the warm period of the year, with peak abundance in June 2012 (21 % of total sample). Lowest plots were always occupied with the highest densities of mud shrimps. Males dominated during the winter while ovigerous females reached the peak in June (>40 % of all animals). In June at least 2/3 of females were ovigerous. Estimated mean incubation period was 31 days. We determined four periods in relation to the species’ reproductive activity. Early reproductive period (April) was characterised by emergence of first ovigerous females, while main reproductive period (May–July) was characterised by peak of reproduction. In post-reproductive (August–October), and non-reproductive (November–March) periods, no ovigerous females or newly hatched offspring were recorded., Istraživali smo sezonsku zastupljenost, vertikalnu raspodjelu i povijesne životne osobitosti Mediteranskog karlića (Upogebia pusilla) u Sloveniji. Na dva lokaliteta (Strunjan i Lazaret) izmjenično su uzeti jednom u dva mjeseca kvantitativni uzorci sa tri parcele (svaki 1 m2 ) na (0 cm), ispod (-50 cm) i iznad (+50 cm) srednje razine vode. Također je zabilježen skup parametara, uključujući vegetacijsku pokrivenost, vrstu sedimenta, temperaturu zraka i mora, pH, salinitet i razinukisika. Najveća zastupljenost zabilježena je tijekom toplog razdoblja godine i to u lipnju 2012 godine (21% ukupnog uzorka). Najviša gustoća karlića bila je zabilježena na najnižim parcelama. Mužjaci su prevladavali tijekom zime dok je najveći broj ovigerih ženki zabilježen u lipnju (>40% svih životinja, ili 2/3 svih ženki u lipnju). Procjenjeni srednji inkubacijski period bio je 31 dan. Utvrdili smo četiri razdoblja u vezi sa reproduktivnom aktivnosti ove vrste. Rano razdoblje reprodukcije bilo je obilježeno pojavom prvih ovigerih ženki u travnju, dok je za vrhunac reprodukcije obilježen reproduktivni period travanj-srpanj. U post-reproduktivnom (kolovoz-listopad) i ne-reproduktivnom periodu (studeni-ožujak) nisu bile zabilježene ovigere ženke ili juvenilne životinje.

Canopy-forming macroalgae, especially those belonging to the order Fucales, are creating the so-called brown algal forests that are considered amongst the most productive assemblages in the shallow coastal area. Moreover, they are biological indicators that are used for the assessment of the status of coastal belts according to important European Directives. Along Mediterranean rocky coasts they are disappearing quickly, Cystoseira species (sensu lato) in particular, and are gradually being replaced by turf-forming smaller and persistent algae, due to multiple anthropogenic pressures. The scope of this research was to verify changes in macrophyte structure and abundance, especially canopy-forming taxa, and the loss of Cystoseira s.l. species at two reference sites for macroalgae in the northern Adriatic Sea, during the period 2007–2019. At both sites, the decline of total Cystoseira s.l. spp. coverage (%) was substantial, both in the spring and autumn samples, while some rare and sensitive species were not found during the last surveys. The results of this study should help improving the conservation status of important canopy-forming species, focusing on the revitalisation of benthic critical habitats.

Sessile benthic communities are an important element of marine ecosystems, yet their temporal patterns remain poorly understood. For this reason, the temporal changes of the fouling community on brick plates in Piran Bay, Gulf of Trieste (northern Adriatic Sea), were studied for two calendar years. The aim of this study was to identify the settlement of dominant native and alien species on artificial substrates and their temporal occurrence, both in terms of season and duration of submersion. In addition, we tried to assess the impact of the placement period on developing communities. The dominant taxonomic groups were bryozoans, which accounted for almost half of the total coverage (46%), serpulid polychaetes (25%) and bivalves (11%). Most of the species belonging to the dominant taxa occurred throughout the year, with the peak of occurrence in summer. The first settlers included serpulids and bivalves, which were constantly found on the plates together with bryozoans. Alien and cryptogenic species represented about 13% of all taxa found during the study. This highlights the importance of bare artificial structures erected outside typical hotspots for alien species; they serve as a springboard for the spread of alien fouling species. The communities that formed on plates placed in different seasons showed significant differences between them. High bryozoan coverage characterized the communities placed in winter and spring, while the plates placed in summer and autumn were dominated by serpulid polychaetes. These differences are the result of species seasonality as well as the interaction between them. The study demonstrates the importance of timing for initial colonization. It can be linked to the placement of the bare substrate for the development of the community, and provides a baseline for research and projects involving underwater constructions and the detection of alien species.

The stony coral Cladocora caespitosa (Linnaeus, 1767) is an important Mediterranean habitat builder, whose survival is now being threatened by human activities and possibly natural events such as mass mortality and bleaching. We characterized the mollusc assemblage associated with colonies in the Gulf of Trieste (northern Adriatic Sea) and then tested whether the number of mollusc species increases in relation with colony size, following a Species-Area Relationship (SAR) model. At least 62 taxa were found in association with coral colonies, with bivalves constituting the dominant group. More than half of the 3034 specimens encountered were juveniles. Mollusc taxa richness increased with increasing C. caespitosa colony size according to the power-function model, whilst the analyses of trophic and functional groups supports the hypothesis of at least two factors underlying SAR (area per se and habitat diversity). Our results confirmed the importance of C. caespitosa for benthic communities, indicating that larger colonies support higher biodiversity, and suggesting that C. caespitosa is the most important habit builder among Mediterranean cnidarians, having also an influential function as a natural nursery ground. These results underline the necessity of new investigations aimed at filling gaps in our knowledge and planning new measures to protect the species.

The tetrasporophyte of the non-indigenous red alga Asparagopsis armata (the Falkenbergia stage) is considered to be established in Slovenian coastal waters. However, until 2016, it was found only in low coverage and in few localities with hard substrata. The paper reports a recent bloom of these tetrasporophytes in the mediolittoral belt of the Bay of Piran, where thalli of this red alga overgrew the articularted coralline alga Corallina officinalis. The sites affected by this large expansion of tetrasporophytes of A. armata should be regularly monitored in the future, in order to point out which environmental factors are responsible for such phenomenon, and to formulate proper conclusions on the status of this non-indigenous alga in the coastal area concerned.

We herein review the Adriatic opisthobranch fauna, provide an updated checklist of 223 species and assess their distribution at regional and country levels. New Adriatic records are provided for 67 opisthobranch taxa, adding three new records for the Italian coastline, five new records for Albania, eight for Croatia and 15 for Montenegro. The presence of Hermaea bifida (Montagu, 1815), Hermaea variopicta (Costa A., 1869) and Facelina annulicornis (Chamisso & Eysenhardt, 1821) is reported for the first time from anywhere in the Adriatic Sea. Including the new findings, our inventory includes 28 species from Albania, 163 from Croatia, 178 from the Italian coastline of the Adriatic, 41 from Montenegro and 74 from Slovenia. No records were available from Bosnia and Hercegovina. Ninety species (40.4%) are widespread, and were recorded from all three main divisions (Northern, Western and Eastern Adriatic), whilst 79 species (35.4%) were reported from only one of them. At sub-division levels, the Albanian inventory is the most dissimilar to the other country/regional lists, presumably because of the lack of targeted field surveys. The highest similarity is observed amongst the Western Adriatic, Croatia and the Italian Ionian coastline. Seven alien, one possible alien and three cryptogenic opisthobranchs were reliably recorded from the Adriatic Sea. The first Mediterranean records of five species were in the Adriatic Sea, of which four species have not been found elsewhere in the Mediterranean. Shipping and aquaculture are the probable pathways for most of the alien species. A steady rate of one to two alien introductions per decade since the 1970s was evident. The Northern Adriatic coasts are the most affected by alien invasions, probably due to repeated local introductions along with shellfish transfers (oysters, mussels, Manila clams), and heavy maritime transport.

Five hundred pellets of the Mediterranean Shag Phalacrocorax aristotelis desmarestii were collected at three roost-sites along the Slovenian coast and analysed. The diet was characterized mostly by the dominance of bottom dwelling fish species of the appropriate size. The Black Goby Gobius niger was the most dominant prey and represented the Shag’s main prey in the studied area (IRI% = 64.0). The results of the study confirm that the Mediterranean Shag preys mainly on fish species which are without commercial value for local fisheries.