Biodiversity and Ecology in the Mediterranean Sea

Dear Colleagues,

We are pleased to announce a forthcoming Special Issue titled “Biodiversity and Ecology in the Mediterranean Sea”.

Marine biodiversity in the Mediterranean Sea, as in many other oceans and seas of the world, has been undergoing extensive modifications in recent years due to the rapidly progressing climate changes we are witnessing. Some Mediterranean typical species are likely to be downsized, and new species adapted to the tropical climate will gain more and more space in Mediterranean waters if the current thermal trend persists.

The Mediterranean is home to more than 17,000 marine species, which corresponds to 4 to 18% of the world’s known marine species; 20–30% of Mediterranean marine species are endemic, being the highest rate of endemism at global level (SoED 2020). This very high biodiversity could be explained by the different climatic and hydrologic conditions that can be found all over the Mediterranean Sea, but also with the old tradition of biological studies carried out in this area. Anyway, more than 1000 non-indigenous marine species have been recorded and 618 species are considered established. Coralligenous ecosystems covering approximately 2760 square kilometers are threatened by fishing gear, boat anchoring, invasive species, pollution and climate change. Moreover, around 70% of habitat loss of Posidonia oceanica is projected by 2050, with the potential for functional extinction by 2100 (IPCC, 2019). From 1950 to 2011, the Mediterranean lost 41% of top predators, including marine mammals. Projections suggest that more than 30 endemic species will become extinct by the end of the century; 75% of Mediterranean and Black Sea stocks (for which validated assessments are available) are fished at biologically unsustainable levels (SoMFi 2020). To try to contrast the abovementioned problems, marine protected areas (MPAs) have been established over the years. Unfortunately, only 9% of Mediterranean marine area is currently protected, and only 10% of MPAs implement management plans. A well-represented biodiversity in a marine area means better functionality of local ecosystems with many benefits for the local populations, including humans. Therefore, it is important to focus on biodiversity-related studies.

Marine ecology could be the key subject to try to interpret how living organisms will interact with physical factors in this rapidly changing environment to have an idea of short–medium term modifications in the biodiversity of the Mediterranean Sea.

This Special Issue is a good opportunity to combine and synthesize recent research focused on biodiversity and ecological studies concerning aquatic organisms of the Mediterranean Sea. We, together with Diversity’s team, kindly invite you to submit a manuscript focused on any of the above topics. Although specific case studies with broad implications are welcome, we encourage authors to submit large-scale and/or multi-specific studies, synthesis works and reviews that could widen our knowledge on the aspects listed above. If you are interested in this opportunity or have any questions, please do not hesitate to contact us.

Dr. Andrea De Felice
Dr. Iole Leonori
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Diversity is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

• biodiversity
• ecology
• mediterranean sea
• plankton
• fish
• environmental factors

Title: Biodiversity of gelatinous organisms in the western Adriatic Sea and identification of their echo traces in acoustic data
Authors: Andrea De Felice; Ilaria Biagiotti; Giovanni Canduci; Ilaria Costantini; Antonio Palermino; Michele Centurelli; Samuele Menicucci; Iole Leonori
Affiliation: National Research Council (CNR), IRBIM-Institute for Marine Biological Resources and Biotechnology, Largo Fiera della Pesca, 60125 Ancona, Italy
Abstract: The abundance of gelatinous organisms, such as salps and jellyfish, in the Adriatic Sea have significantly increased over the past decade. Environmental factors play a key role in driving this shift in abundance through rising temperatures and a consequent decrease in oxygen levels in the water, for which jellyfish have higher tolerance levels. Additionally, fisheries may contribute to the proliferation of jellyfish by diminishing their natural predators and food competitors. Pelagic trawl catch data from 2015 to 2023 acquired during MEDIAS acoustic surveys in the western Adriatic Sea were reviewed to extract information concerning the abundance and distribution of salps and jellyfish. These data were subsequently analyzed and compared with satellite environmental information to identify potential correlations. When considering environmental information from the survey month, the results show significant relationships between the abundance of A. aequorea and average salinity and the abundance of R. pulmo and bottom temperature. Furthermore, when considering environmental data from the month preceding the survey, a relationship between the overall abundance of gelatinous organisms and surface temperature was identified. Additionally, an analysis was conducted on specific hauls that almost exclusively yielded jellyfish, with the aim of identifying their echo traces. Although it was not possible to allocate one jellyfish species to a specific echo trace due to the frequent co-occurrence of more than one species, a general indication of typical backscatter for these species, with a higher response at 70 kHz, was consistently observed in all cases examined.