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Mediterranean coralligenous assemblages are threatened by the effects of climate change and human activities that have led to mass mortality events (MMEs) in recent decades. The ecological roles of this habitat and the possible consequences of its loss have necessitated the scientific analysis of MMEs on a Mediterranean regional scale, highlighting the need of new standardized monitoring and data collection tools across the basin. In September 2021, during the monitoring activities of the Marine Strategy Framework Directive (MSFD) for the coralligenous habitat of the Egadi Islands Marine Protected Area (MPA), an MME of the red gorgonian Paramuricea clavata was recorded. Five of the six surveyed sites revealed a high degree of impact, with mortality values ranging from 46.9% in the least affected site to 100% in the most affected. The observed MME occurred during a prolonged period of anomalous warmer sea temperatures down to 60 m in depth. By enhancing the MSFD protocols for coralligenous habitat with the addition of a series of biotic/abiotic variables (e.g., temperature, pH and mucilaginous bloom) and methodologies (e.g., scuba survey and citizen science activities) to evaluate and monitor Good Environment Status (GES), we propose to implement a monitoring and data collection system which is able to provide essential information about MMEs. This multiple shared surveillance tool would allow the tracking of MME events in the Mediterranean region, as well as the planning of mitigation and/or restoration strategies for these vulnerable habitats on an inter-regional scale.

Saltworks are peculiar artificial ecosystems and holds great interest for basic research. In fact the cooling vat (the first pond of the evaporating series) is a good example of a relatively closed area and can be considered an excellent in the field open-air laboratory, namely a mesocosm reproducing a simplified model of the natural condition of hyperaline lagoons. The aim of the present work was to analyse the structure, composition and distribution of molluscan assemblages and to identify the faunistic relationships between the cooling vat and the neighbouring basin of Stagnone di Marsala, beside considering exchanges between saltwork, Stagnone di Marsala and sea, on soft- bottom, covered by Cymodocea nodosa. In structural terms, two molluscan communities can be identified. As regard the saltwork, the community was always characterized by halolimnobic and euryaline species such as Ventrosia ventrosa, Loripes lacteus, Abra segmentum and Pirenella conica. while the community inhabiting Stagnone was composed mainly of marine taxa; here a good exchange with the sea is confirmed by the high values for species richness and diversity gives rise mainly to the presence of marine taxa: e. g Jujubinus striatus, Dikoleps nitens, Rissoa paradoxa, R. similis, Columbella rustica etc. The saltwork molluscan assemblage doesn’t seem to be similar to that of the Stagnone. The low specific richness, the high abundance and the low evenness, showed a pioneer stage of colonization, being poor in species and dominated by taxa with high abundance and low evenness

The gastropod Dendropoma cristatum is a biogenic engineer of the central Mediterranean, forming reefs along the lower rocky intertidal fringe with a remarkable ecological role. To understand whether reef-associated biofilm cultivable bacterial and biofilm ageing may trigger the settlement of the juvenile snails, a combination of laboratory techniques and field experiments was used. Reef-associated biofilm cultivable bacteria were isolated, and a settlement-choice experiment was performed in situ on artificial biofilms composed of i) a mixture of six biofilm-forming selected isolates, ii) all the cultivable bacteria, and iii) 13-, 23-, 32-day old biofilms formed under naturalconditions. Overall,settlement ratesignificantlydifferedamong biofilmtreatments(p < 0.0001). A significant positive correlation between biofilm ageing and juvenile D. cristatum settlement was assessed (r=0.69 (p < 0.001), whereas the biofilm bacterial composition (relatively to the cultivable fraction) did not show any effect on the vermetid's settlement rate.

The establishment of non-indigenous species is one of the major threats to Mediterranean biodiversity. The tropical red macroalga Asparagopsis taxiformis is widely distributed in the Mediterranean Sea and appears invasive along the shallow rocky areas of western Sicily (Italy). Here it competes for space with the native brown macroalgae of the genus Cystoseira, in particular with C. brachycarpa, a valuable Mediterranean habitat former. This research aims to evaluate the potential effects of invasion of A. taxiformis on the polychaete assemblages associated with C. brachycarpa. Polychaetes were sorted from Cystoseira and Asparagopsis thalli collected along the Favignana Island (Sicily) in the rocky infralittoral algal community from four locations with different degree of invasion: 1) non-invaded, 2) invaded but dominated by Cystoseira, 3) invaded and dominated by Asparagopsis, 4) completely invaded. Ten replicates of each algal thalli were collected from two sites per location. Structure of polychaete assemblages changed significantly among degree of invasion. Reductions of average polychaete abundance and species richness occurred with invasion, with 58 individuals and 12 species per thallus on non-invaded location, only 4 individuals and 2 species on completely invaded location, and almost equal, intermediate values, on two partially invaded locations. Decrease of abundance was mainly caused by the decrease of sabellid Amphiglena mediterranea and syllids Syllis prolifera and Sphaerosyllis austriaca. These results raise concerns on the spread of non-indigenous habitat forming species and their potential impact on biodiversity at local scale.

A consistent living population of Panopea glycimeris (von Born, 1778) was documented underwater along the eastern coast of Sicily. Twenty specimens were counted over an area of 1000 m(2), with an estimated total population of less than 300 individuals. The morphometric measurements of an adult specimen captured are provided. Proposals to adopt protection measures for this species are discussed.

Despite the increasing number of monitoring programs and local-scale experiments evaluating the efficacy of conservation interventions, there is still a lack of conclusive evidence about whether spatial approaches to marine management and conservation are effective in sustaining fisheries and conserving biodiversity. Here, we used data on benthic assemblages of hard substrates collected in 15 Marine Protected Areas, within the framework of a large-scale research program (Afrodite-Venere). This is the first coordinated effort of quantifying potential effect of protection including all Italian MPAs using a common sampling design. The general outcomes are: 1- most MPAs do not show any effect of protection, maybe also because restrictions are not effectively enforced; 2- significant differences were consistently detected when the integral zone was located on islands, generating the hypothesis that, in some cases, differences are driven by habitat more than protection itself (i.e., lack of appropriate spatial controls). In highly heterogeneous environments, such as Mediterranean ones, successful use of MPAs in marine conservation and management will likely require a case-by-case understanding of the specific patterns of resource use and human threats impacting local habitats and assemblages, as well as the ecological characteristics of those species and systems.