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The aim of this study is to synthesize available information on sea pens in the Mediterranean Sea and fill existing knowledge gaps through modelling of suitable habitat, with the overarching goal of informing strategies for protecting sea pen habitats from trawling impacts and facilitating their recovery. A review spanning the last 30 years was conducted to map the distribution of Mediterranean sea pen species. In the Adriatic Sea, presence–absence data were modelled with generalized additive models (GAMs) to identify potentially suitable habitats for Funiculina quadrangularis, Virgularia mirabilis, and Pennatula spp. Results show that sea pen distribution in the Mediterranean is mainly limited to continental northern shelves. Six species have been recorded throughout the Adriatic basin, where habitat suitability models confirm that its soft bottoms yield favourable conditions for sea pen assemblages. This information can help guide strategies for diminishing and reversing the impacts of bottom trawling on these vulnerable habitats. [ABSTRACT FROM AUTHOR]

The aim of this paper is to highlight current opportunities and expected benefits of establishing a transboundary large marine protected area (LMPA)-specifically a no-trawl area – in one of the most exploited sectors of the Mediterranean, the Adriatic Sea. A no-trawl area is examined as a strategy to foster recovery of the local marine ecosystems and economies, and to meet international conservation targets and EU legal mandates. Based on a review of published studies documenting the positive outcomes of previous trawling bans in other regions, and of current initiatives and opportunities within the Mediterranean region, it is concluded that large-scale protection of the Adriatic with a no-trawl zone is a promising and feasible approach for reversing ecological and socioeconomic losses in this basin. In particular, ecosystem protection can be established in the Mediterranean through a proposal for a Fisheries Restricted Area (FRA) to the general Fisheries Commission for the Mediterranean (GFCM). The successful establishment and function of a FRA or LMPA will depend on its support by the governments of the surrounding countries, as well as involvement and participation of key user groups. [ABSTRACT FROM AUTHOR]

Massive outbreaks are increasing all over the world, which are likely related to climate change. The North Adriatic Sea, a sub-basin of the Mediterranean Sea, is a shallow semi-closed sea receiving high nutrients inputs from important rivers. These inputs sustain the highest productive basin of the Mediterranean Sea. Moreover, this area shows a high number of endemisms probably due to the high diversity of environmental conditions and the conspicuous food availability. Here, we documented two massive mortalities (2009 and 2011) and the pattern of recovery of the affected biocoenoses in the next two years. Results show an impressive and fast shift of the benthic assemblage from a biocoenosis mainly composed of slow-growing and long-lived species to a biocoenosis dominated by fast-growing and short-lived species. The sponge Chondrosia reniformis, one of the key species of this assemblage, which had never been involved in previous massive mortality events in the Mediterranean Sea, reduced its coverage by 70%, and only few small specimens survived. All the damaged sponges, together with many associated organisms, were detached by rough-sea conditions, leaving large bare areas on the rocky wall. Almost three years after the disease, the survived specimens of C. reniformis did not increase significantly in size, while the bare areas were colonized by fast-growing species such as stoloniferans, hydrozoans, mussels, algae, serpulids and bryozoans. Cnidarians were more resilient than massive sponges since they quickly recovered in less than one month. In the study area, the last two outbreaks caused a reduction in the filtration efficiency of the local benthic assemblage by over 60%. The analysis of the times series of wave heights and temperature revealed that the conditions in summer 2011 were not so extreme as to justify severe mass mortality, suggesting the occurrence of other factors which triggered the disease. The long-term observations of a benthic assemblage in the NW Adriatic Sea allowed us to monitor its dynamics before, during and after the mortality event. The N Adriatic Sea responds quickly to climatic anomalies and other environmental stresses because of the reduced dimension of the basin. The long-term consequences of frequent mass mortality episodes in this area could promote the shift from biocoenoses dominated by slow-growing and long-lived species to assemblages dominated by plastic and short life cycle species. [ABSTRACT FROM AUTHOR]

A mass mortality episode involving three marine dyctioceratid sponges, Ircina variabilis, Sarcotragus spinosulus and Spongia officinalis, was observed on 'Scoglio del Trave' (Conero Promontory, North Adriatic Sea) in late summer 2009. In this area, calm sea and high temperatures throughout summer created unfavorable environmental conditions, leading to the outbreak of the disease. Affected specimens showed evident necrotic areas and portions with bare skeleton, and many specimens of S. spinosulus were covered with a white mat of cyanobacteria. In September 2009, about 22% of these demosponges suffered from this disease. The mortality event ceased when sea temperature dropped below 20 °C. Small specimens turned out to be more sensitive to the diseases, whereas the damaged tissues of large specimens were able to recover. In October, the damaged specimens were detached by the rough sea and more than 900 beached sponges were found along the 1-km-long beach, showing the seriousness of the phenomenon, which probably involved not only the area studied but also areas adjacent to it. [ABSTRACT FROM AUTHOR]

The North Adriatic Sea is a shallow basin characterized by peculiar trophic and hydrologic conditions affecting the composition, species abundance and seasonal cycles of the benthic assemblages. Due to high productivity rates comparable to those of the north seas, here the benthic organisms reach sizes or densities significantly higher than the same species observed in other Mediterranean localities and show wider periods of reproduction. Concerning the dynamics of zoanthids, there are very few studies about these Mediterranean species, and this research is the first on the abundance and reproduction of Epizoanthus arenaceus . The zoanthid from shallow waters of the NW Adriatic Sea has a maximum abundance of 25,000 polyps m − 2 (about 40 g C m − 2 ). E. arenaceus shows a growth phase during winter and a regression period from summer to autumn coinciding with gametogenesis. During summer, the decreases in current intensity and prey concentration combined with the increase in the reproductive effort may cause shrinkage and fission/fragmentation of the colonies. On the contrary, the maturation and release of gametes are positively correlated with the temperature trend. A temporal and spatial separation of the production of male and female gametes was observed, leading us to hypothesize that temperature could affect sex determination. The comparison of patterns in abundance and reproduction at 3–4 m and 6–7 m shows that the shallower colonies seem to be more sensitive to extreme values of temperature. The NW sector of the Adriatic Sea, vulnerable to severe anthropogenic pressure and subject to frequent thermal anomalies, is particularly prone to the mortality episodes of benthic organisms. For these reasons, the study of the dynamics of invertebrates from this area is crucial to forecast the effects of environmental changes in the entire Mediterranean basin. [ABSTRACT FROM AUTHOR]