This Collective Article presents information on 37 taxa belonging to 6 Phyla and extending from the western Mediterranean to the Levantine Sea. The new records were found in 10 countries as follows: Algeria: first reports on the presence of the fish species Lesueurigobius sanzi, L. friesii, L. suerii and Luvarus imperiali; France: first record of the alien nudibranch Godiva quadricolor; Italy: first record of an adult-sized red emperor snapper Lutjanus sebae from the southern Tyrrhenian Sea; first record of the pantropical rhodophyte Chondria curvilineata and the Lessepsian fish Siganus luridus from southern Sicily; record of a large pregnant female Dusky shark Carcharhinus obscurus off Sicily; Albania: first record of the fish Ruvettus pretiosus, new records of the alien molluscs Conomurex persicus, Bursatella leachii, Dendostrea cf. folium, Fulvia fragilis and Ruditapes philippinarum and additional report of the alien bivalve Pinctada imbricata radiata; Montenegro: first record of the sea slug Thecacera pennigera in the Adriatic Sea; Greece: first record of the invasive calcarean sponge Paraleucilla magna in Greek waters; occupancy estimation of the established cryptogenic rhodophyte Ganonema farinosum, the alien crustacean Percnon gibbesi and the alien fish species Fistularia commersonii, Siganus luridus, and S. rivulatus along the Cretan coastline; first record of the alien mollusc Sticteulima lentiginosa in Greek waters suggesting a westward unintentional expansion of this species; Turkey: photographic evidence of interactions of the monk seal Monachus monachus with sea-cage farms in the Turkish Aegean Sea and first record of the yellow boxfish Ostracion cubicus in the Turkish Mediterranean; Cyprus: first records of the rare speleophilic fish Thorogobius ephippiatus and Grammonus ater in Cyprus, extending the known distribution of the latter Mediterranean endemic species eastwards; first records of the alien fish Kyphosus vaigiensis and the alien crustacean species Macrophthalmus indicus and Carupa tenuipes as well as additional records of the alien echinoderm Diadema setosum and the alien ascidian Symplegma brakenhielmi in the country; Lebanon: first report on the presence of the four alien fish species Cephalopholis taeniops, Equulites popei, Pseudupeneus prayensis and Sphoeroides pachygaster; Egypt: first record of the Lessepsian fish Synchiropus sechellensis in the Egyptian Mediterranean waters.

Marine organisms represent an enormous reservoir of compounds with many potential applications. Microbes, vegetals and animals from the sea have been exploited for numerous purposes. From seaweeds, in particular, many active compounds can be obtained, such as three important phycocolloids: agar, carrageenan and algin. In this report, an overview is given about biological characteristics, cultivation, agar and bioactive molecules content of the Rhodophyta Gracilaria gracilis; also, agar extraction processes and its traditional and innovative applications are discussed. Cultivation of G. gracilis is subject of several studies and experiments, because there is still much to understand for improving productivity and biomass yield. G. gracilis is one of the best candidates for cultivation and consequent agar extraction, thanks to: fast growth rate, ease of vegetative reproduction, good resistance to salinity and temperature oscillation, good agar qualities. The possibility of farming G. gracilis opens positive perspectives if some factors are taken into account: constant availability of raw material for agar extraction and preservation of ecological balances in natural environments. Agar extraction methods have been also reviewed in terms of improvement related to both agar yield and agar gel strength. As widely acknowledged, the main uses of agar are related to formation of thermoreversible gels at low concentrations in water. It exhibits also many beneficial biological activities including anticoagulant, antiviral, antioxidative, anticancer and immune- modulating activities. Newest applications of agar in pharmaceutical, medical, engineering and other fields are of great interest and are the topic of current and future studies.

In this Collective Article on “New Mediterranean Biodiversity Records”, we present additional records of species found in the Mediterranean Sea. These records refer to eight different countries throughout the northern part of the basin, and include 28 species, belonging to five phyla. The findings per country include the following species: Spain: Callinectes sapidus and Chelidonura fulvipunctata; Monaco: Aplysia dactylomela; Italy: Charybdis (Charybdis) feriata, Carcharodon carcharias, Seriola fasciata, and Siganus rivulatus; Malta: Pomacanthus asfur; Croatia: Lagocephalus sceleratus and Pomadasys incisus; Montenegro: Lagocephalus sceleratus; Greece: Amathia (Zoobotryon) verticillata, Atys cf. macandrewii, Cerithium scabridum, Chama pacifica, Dendostrea cf. folium, Ergalatax junionae, Septifer cumingii, Syphonota geographica, Syrnola fasciata, Oxyurichthys petersi, Scarus ghobban, Scorpaena maderensis, Solea aegyptiaca and Upeneus pori; Turkey: Lobotes surinamensis, Ruvettus pretiosus and Ophiocten abyssicolum. In the current article, the presence of Taractes rubescens (Jordan & Evermann, 1887) is recorded for the first time in the Mediterranean from Italy. The great contribution of citizen scientists in monitoring biodiversity records is reflected herein, as 10% of the authors are citizen scientists, and contributed 37.5% of the new findings.

This paper is a collection of novel distributional records of 20 species belonging to 8 phyla (Chlorophyta, Rhodophyta, Cnidaria, Ctenophora, Annelida, Mollusca, Arthropoda and Chordata) from 11 Mediterranean countries, namely, Spain: an additional record of the Canary dentex Dentex canariensis is reported from Spain (Valencia), this is the northernmost record of this species in the Mediterranean; Algeria: the first documented record of Caulerpa chemnitzia is reported from the Algerian coast; France: the first record of the Spotted sea hare Aplysia dactylomela is reported from the eastern coast of Corsica; Italy: the first records of the Lessepsian polychaete Dorvillea similis and the alien bivalve Isognomon legumen are reported from Italian waters while additional records of Mnemiopsis leidyi in the south Adriatic are provided; Libya: the first record of an alien mollusc Crepidula fornicata is reported from Libyan waters; Malta: multiple sightings of gelatinous species Apolemia uvaria, Phacellophora camtschatica and Physophora hydrostatica are reported for the first time from Maltese waters, as well as the first tentative record of the Orange-spotted grouper Epinephelus cfr. coioides; Greece: an occurrence of a rare Bigeye thresher shark Alopias superciliosus is reported from Hellenic Ionian waters, while the first records of the alien Mertens’ prawn-goby Vanderhorstia mertensi, the recently described cyclopoid copepod Oithona davisae and the alien red seaweed Asparagopsis armata are reported from the Aegean Sea. The presence of the micromollusc Euthymella colzumensis is confirmed for Greece; Cyprus: the first record of the red cornetfish Fistularia petimba is reported from Cyprus; Turkey: the first record of the alien jellyfish Marivagia stellata is reported from south-eastern Turkey; Israel: the first records of the sea nettle Chrysaora sp. in the Levant are reported.

The fan mussel Pinna nobilis is threatened by several anthropogenic disturbances that are only partially mitigated by current conservation measures. In the Faro Lake Natural Reserve, the fan mussel population suffers from insufficient recruitment while, due to periodic dredging, a high larval supply within the canals does not support a stable population. In the present study, a robust number of fan mussel specimens were transplanted from a high-impact site to a guarded area to test the effects of transplantation on future conservation efforts. Over a 12-mo period, high survival and elevated growth were observed in the test population in comparison with the local population, demonstrating transplantation as a feasible and efficient method to prevent P. nobilis population decline. Such small-scale experiments provide useful indications for better management approaches for both of the threatened species and the natural hosting environment.