The Atlantic blue crab Callinectes sapidus occurs as an invasive alien species in the Mediterranean, where it has successfully colonized the entire basin, exerting a negative impact on fisheries in some areas. This paper presents the results of a study on the movement ecology of blue crabs in the S’Ena Arrubia lagoon, a shallow, oligohaline, semi-enclosed water body used for extensive aquaculture in Sardinia (western Mediterranean). The specific objective was to investigate movements and home range of blue crabs in the lagoon and evaluate the effect of temperature on movement patterns. An array of 15 receivers was deployed in the lagoon. Two batches of adult blue crabs were tagged with external ultrasonic transmitters: a first lot (5 males and 5 females) was released in December 2022, and a second lot (10 females) in June 2023. Monitoring lasted 290 days for the first lot and 202 days for the second. Residency and movement index, daily home range (MCPd), and Vemco Positioning System (VPS) data were used to describe crab movements and activity patterns. Residency and movement indexes were larger than 80

The Egadi Islands Marine Protected Area (EI-MPA, central Mediterranean) is a large MPA characterized by an economy based on tourism and artisanal fishing embedded in a complex governance structure. The discovery of an aggregation site for the common eagle ray, Myliobatis aquila has boosted its touristic attractiveness, especially as regards scuba diving. We have applied an approach based on the Q methodology to assess the perceptions of the main stakeholder categories concerning the presence of the common eagle ray aggregation and its effects on local economy. Thirty statements (the Q-set) were submitted to 13 participants (the P-set). The discourses highlighted by the Q analysis were grouped in four visions: (1) collaborative stewardship, (2) sufficiency, (3) evidence-driven coexistence, and (4) eco-centrism. A synthesis of identified conflicts, the identification of their sources, the interpretation of visions in terms of management perspectives and the possible pathways towards consensus were provided. The analysis of the four visions suggests that the opinions of local stakeholders are different in terms of acceptance of institutional actions, levels of regulation, and socio-economic implications of the potential conservation measures. We suggest that establishing a formal, permanent dialogue mechanism involving the MPA authority, fishers, diving operators, tourism service providers, scientists, and enforcement agencies, which takes into consideration economical as well as ecological issues would provide the basis for a shared and accepted management of the common eagle ray aggregation and for its conservation.

Seagrass meadows are experiencing a worldwide decline, driven by human activities and natural disturbances. The degradation of these meadows raises significant concerns regarding the loss of essential ecosystem services. Posidonia oceanica, a Mediterranean endemic seagrass, plays a crucial role in coastal ecosystems, contributing to biodiversity, carbon storage, water purification, and shoreline protection. This study reports the outcomes of a six-year transplantation experiment aimed at restoring small damaged patches in a Posidonia oceanica meadow in the southwestern Tyrrhenian Sea, within the Egadi Marine Protected Area (MPA). The damage, likely caused by boat anchoring, was addressed using seedlings grown in the laboratory from beach-cast seeds. The experiment evaluated the survival and growth of seedlings planted at three different densities in two sites. After six years, the intermediate planting density (100 seedlings per m2) yielded the highest survival rate (76.9 %), while the lowest density (40 seedlings per m2) resulted in the lowest survival rate (5.1 %). Seedlings showed significantly different growth rates and biomass accumulation in the two sites, likely due to variability in sediment accumulation, seabed slope and hydrodynamic conditions. This research highlights the potential of seed-based techniques for restoring seagrass meadows, emphasizing that long-term monitoring and careful selection of transplant sites are essential for the success of such restoration efforts.

In this study, we investigate the habitat suitability and distribution patterns of two invasive alien crab species, Callinectes sapidus and Portunus segnis, in the Mediterranean basin. Using a comprehensive dataset compiled from multiple sources, including bibliographic records, online databases, and online informal sources, we mapped the occurrences of these species and overlaid them with environmental variables obtained from the Copernicus Marine Service. We employed MaxEnt species distribution models to predict habitat suitability, considering variables such as sea surface temperature, salinity, chlorophyll, and oxygen. Our results indicate widespread distribution of C. sapidus across the basin, with notable concentrations in certain areas, while P. segnis exhibits a predominantly southern distribution. Model evaluations demonstrate high predictive performance, with average AUC (area under the receiver operating characteristic curve) values exceeding 0.85. Additionally, we assessed potential habitat overlap between the two species at different probability thresholds, revealing regions where coexistence is likely. Our findings provide valuable insights into the spatial dynamics of invasive alien crab species in the Mediterranean and contribute to ongoing efforts in biodiversity conservation and management.

The non-indigenous crustaceans Erugosquilla massavensis (Stomatopoda, Squillidae), Penaeus aztecus (Decapoda, Penaeidae) and Portunus segnis (Decapoda, Portunidae) are reported for the first time from the southern Tyrrhenian Sea (Gulf of Castellammare, NW Sicily) as a consequence of distribution range expansion. Their size and weight are provided along with the main distinguishing morphological characters. The presumed impacts on the ecosystem and the possible effect on the small-scale fishery of the Gulf of Castellammare are briefly discussed.

Bottom trawling causes detrimental effects on marine ecosystems, and significantly alter benthic communities, potentially affecting the diet and trophic role of benthic feeders. The ban on bottom trawling is a common spatial fishing restriction that has been implemented in tropical and temperate regions to restore overexploited marine resources and ecosystems. In northern Sicily (central Mediterranean Sea) two trawl ban areas, the Gulf of Castellammare and the Gulf of Patti, were established in 1990. In both gulfs, the red mullet Mullus barbatus, a commercially important demersal fish and benthic feeder main target of bottom trawlers, has since experienced an impressive increase in biomass. We investigated the stomach contents, prey selectivity, and trophic position (using carbon and nitrogen stable isotope analysis) of red mullet in the two untrawled gulfs and compared the results with two trawled gulfs. Our results show that bottom trawling affects the diet and trophic position of red mullet following the trophic erosion process. In untrawled areas, the species feeds in a less disturbed and well-structured benthic community at a higher trophic position, while in trawled areas it benefits from the more opportunistic epibenthic fauna associated with trawling-induced resuspension of organic matter.

The reticulated leatherjacket Stephanolepis diaspros and the Por's goatfish Upeneus pori occur as lessepsian migrants in the eastern and central Mediterranean Sea. This article reports on the findings of one reticulated leatherjacket and two Por's goatfishes in the Gulf of Castellammare, southern Tyrrhenian Sea, which suggest a possible westbound expansion of the Mediterranean distribution for the latter species. The specimens were three adults collected by professional fishermen on inshore sandy bottoms with a trammel net. The main meristic characteristics of both species, the identification issues of S. diaspros, and the potential impact of U. pori on the native biota and artisanal fisheries are briefly discussed.

Fishing has significant trophodynamic impacts on marine communities, including reductions in the mean trophic position (TP) of the ecosystem resulting from a decrease in the abundance and size of species and individuals with high TPs. This study demonstrates the erosion of fish TP, an additional process that results in lower TP of individuals of a given size, which may exacerbate the effects of fishing on the food web. A stable isotope approach based on the tRophicPosition Bayesian method was used to quantify the TP of 12 target marine species at a given length, and compare their TP between fishery-restricted areas and trawled areas. The results show a difference in the TP of six benthic and apical nekto-benthic predators, which feed in the median at about 0.5 TP lower in trawled areas. It appears that current ‘fishing down marine food webs’ analyses may underestimate the trophic effects of fishing. Accounting for changes in trophodynamics of individuals at a given size is important to detect indirect effects through food web interactions. The application of a trawling ban may lead to the restoration of lost trophic structure; however, trophic changes may occur more slowly than changes in biomass. This article is part of the theme issue ‘Connected interactions: enriching food web research by spatial and social interactions’.

The reticulated leatherjacket Stephanolepis diaspros and the Por’s goatfish Upeneus pori occur as lessepsian migrants in the eastern and central Mediterranean Sea. This article reports about the findings of one reticulated leatherjacket and two Por’s goatfishes in the Gulf of Castellammare, southern Tyrrhenian Sea, which suggest a possible westbound expansion of the Mediterranean distribution for the latter species. The specimens were three adults collected by professional fishermen on inshore sandy bottoms with a trammel net. The main meristic characters of both species, the identification issues in S. diaspros and the potential impact of U. pori on the native biota and on artisanal fisheries are briefly discussed.

The Aarhus Convention is a globally recognised benchmark for democratic environmental governance. However, no assessment exists on whether European MPAs comply with the legal standards set out by the Convention. Here, we focus on public authorities’ websites on MPAs as tools for promoting transparency, public involvement, and democratic processes. We assessed the websites of 61 European MPAs in thirteen countries using a survey structured by the three pillars of the Convention: access to information, participation in decision-making, and access to justice. We show that while most websites are used to disseminate information, they do not serve yet as participatory instruments. Very few have an area dedicated to public participation in decision-making and, when available, they provide scarce information on the outcomes of public involvement. Most websites provide general information on the MPA conservation objectives, but less than half provide access to reports on the results of management. Few websites provide information on available means to challenge unlawful acts. Websites’ potential as one of the most widely used, easily accessible, cost-effective sources of information and means for interaction with the general public should be better exploited. Increasing and facilitating the ability of the public to participate in MPA processes is key to ensure MPA success and environmental justice.

The collection of Crustacea preserved in the Museum of Zoology "P. Doderlein" in Palermo (Italy) has been revised in the framework of the activities of the National Biodiversity Future Center. The main part of the collection is composed of Decapoda, while a smaller part includes Stomatopoda, Isopoda, Amphipoda, and Cirripedia. Overall the collection includes common species, some of which are now protected.

This paper reports the results of a 15-year trawl ban imposed in 1990 in the Gulf of Castellammare (GCAST: NW Sicily, central Mediterranean Sea) and its effects on the biomass and size structure of demersal finfish and shellfish and on the proportion of different commercial categories of fish. Data were collected by experimental trawl surveys conducted in the GCAST and in two trawled areas before and after 1990. The biomass of the total assemblage and of a number of selected species was significantly higher in the GCAST after the ban. Highly commercial species had the largest increase in the same gulf after the ban, particularly at the depths used by artisanal fishermen. The results from size-based indicators were not as clear-cut as those from biomass though. Although the length frequency distributions obtained in the GCAST were significantly different from the other gulfs, in several cases, the values of the size indicators were higher in the trawled gulfs. Our results suggest that, at the temporal and spatial scale adopted, trawl bans may drive full biomass recovery but only partial size structure recovery of the fish populations subject to trawl exclusion, at least in the Mediterranean. The trawl ban in the Gulf of Castellammare provides an example of an effective ecosystem-based fisheries management tool that offers the potential for fish stock rebuilding and for the economic sustainability of artisanal, small-scale fisheries.

Marine habitat-forming species create structurally complex habitats that host macroinvertebrate communities characterized by remarkable abundance and species richness. These habitat-forming species also play a fundamental role in creating favourable environmental conditions that promote biodiversity. The deployment of artificial structures is becoming a common practice to help offset habitat loss although with mixed results. This study investigated the suitability of artificial flexible turfs mimicking the articulated coralline algae (mimics) as habitat providers and the effect of ocean acidification (OA) on early stage ecological communities associated to flexible mimics and with the mature community associated to Ellisolandia elongata natural turfs. The mimics proved to be a suitable habitat for early stage communities. During the OA mesocosms experiment, the two substrates have been treated and analysed separately due to the difference between the two communities. For early stage ecological communities associated with the mimics, the lack of a biologically active substrate does not exacerbate the effect of OA. In fact, no significant differences were found between treatments in crustaceans, molluscs and polychaetes diversity and abundance associated with the mimics. In mature communities associated with natural turfs, buffering capability of E. elongata is supporting different taxonomic groups, except for molluscs, greatly susceptible to OA.

The white seabream Diplodus sargus (L., 1758) (Osteichthyes, Sparidae) is a littoral species living mainly in rocky habitats and distributed in the eastern Atlantic and the Mediterranean. This species is targeted by artisanal and recreational fisheries and presents a high commercial importance. Although classified by IUCN as a "least concern" species, it has been the object of marine ranching and restocking initiatives to counteract locally intense exploitation. Here, we review the current knowledge on the movement ecology of white seabream given the relevance of animal movement in ecological and behavioral studies and their potential application in management and conservation. The literature on this topic was analyzed in order to summarize the results of past research and to identify the gaps that still exist on the matter. We reviewed a total of 27 papers focusing on the movement ecology of white seabream, where acoustic telemetry (n = 12), underwater visual observation and traditional tagging (n = 6), genetic analysis (n = 6), and otolith microchemistry (n = 3) were used. While the first three methods were applied to juvenile and adult fish, the last one was also used with larvae, which have been the object of experimental trials to ascertain their swimming abilities. The largest amount of information on activity rhythms (diurnal with a few exceptions), movement patterns (short distances), homing (ability to come back to the capture site), site fidelity (high), and home range (< 200 ha on average and highly related with seabed morphology) were obtained through acoustic telemetry, whose main limitation is the minimum body size required for its application. The environmental variables found to affect movement patterns in this species are water temperature (which triggers spawning-based vertical movements), local sea conditions (which affect short-scale movements in juveniles), and the main seabed features (orientation and habitat type). The main gaps identified, which need more extensive research and some technological improvements, include the study of the effects of environmental variables on fish movements and further investigations on the movement patterns of juveniles.

Local, regional and global targets have been set to halt marine biodiversity loss. Europe has set its own policy targets to achieve Good Environmental Status (GES) of marine ecosystems by implementing the Marine Strategy Framework Directive (MSFD) across member states. We combined an extensive dataset across five Mediterranean ecoregions including 26 Marine Protected Areas (MPAs), their reference unprotected areas, and a no-trawl case study. Our aim was to assess if MPAs reach GES, if their effects are local or can be detected at ecoregion level or up to a Mediterranean scale, and which are the ecosystem components driving GES achievement. This was undertaken by using the analytical tool NEAT (Nested Environmental status Assessment Tool), which allows an integrated assessment of the status of marine systems. We adopted an ecosystem approach by integrating data from several ecosystem components: the seagrass Posidonia oceanica, macroalgae, sea urchins and fish. Thresholds to define the GES were set by dedicated workshops and literature review. In the Western Mediterranean, most MPAs are in good/high status, with P. oceanica and fish driving this result within MPAs. However, GES is achieved only at a local level, and the Mediterranean Sea, as a whole, results in a moderate environmental status. Macroalgal forests are overall in bad condition, confirming their status at risk. The results are significantly affected by the assumption that discrete observations over small spatial scales are representative of the total extension investigated. This calls for large-scale, dedicated assessments to realistically detect environmental status changes under different conditions. Understanding MPAs effectiveness in reaching GES is crucial to assess their role as sentinel observatories of marine systems. MPAs and trawling bans can locally contribute to the attainment of GES and to the fulfillment of the MSFD objectives. Building confidence in setting thresholds between GES and non-GES, investing in long-term monitoring, increasing the spatial extent of sampling areas, rethinking and broadening the scope of complementary tools of protection (e.g., Natura 2000 Sites), are indicated as solutions to ameliorate the status of the basin.

This study evaluates the effects of a trawling ban on the growth of young-of-the-year (YOY) European hake, Merluccius merluccius (L., 1758) by comparing size structure, length-weight relationship, condition and growth in three gulfs along the coast of northern Sicily (central Mediterranean Sea), one of which has been subject to a trawl ban for 15 years. Hake ranging between 60 and 330 mm were collected from 50 to 200 m depth in May 2005. The length frequency distribution of YOY fish showed a higher modal length in the untrawled gulf and comparable densities in the three gulfs, while larger fish were more abundant in the untrawled gulf. Length-weight relationships and condition factors did not highlight any trend linked to the effects of fishing and suggested a large variability of the system. Growth curves had comparable slopes while different intercepts in both length-weight and growth curves suggest that the observed larger modal size of the first cohort in the untrawled gulf could be linked to better condition and growth during the initial life stage in the pelagic environment. (c) 2021 Elsevier B.V. All rights reserved.

Disentangling the effects of mixed fisheries and climate change across entire food-webs requires a description of ecosystems using tools that can quantify interactive effects as well as bio-economic aspects. A calibrated dynamic model for the Sicily Channel food web, made up of 72 functional groups and including 13 fleet segments, was developed. A temporal simulation until 2050 was conducted to evaluate the bio-economic interactive effects of the reduction of bottom trawling fishing effort by exploring different scenarios that combine fishery and climate change. Our results indicate that direct and indirect effects produce a net increase in biomass of many functional groups with immediate decline of trawlers’ catches and economic incomes, followed by a long term increase mainly due to biomass rebuilding of commercial species which lasts 5-10 years after fishing reduction. Synergistic and antagonistic effects caused by changes in the fishing effort and in climate characterize a specific functional group’s response in biomass which, in turn, modulate also the catch and income of the other fleets, and especially of those sharing target resources. However, trawler’s intra-fleet competition is higher than the others fleet effects. In the medium term, the effects of fishing effort reduction are higher than those of climate change and seem to make exploitation of marine resources more sustainable over time and fishery processes more efficient by improving ecosystem health.

The development and monitoring of ecological indicators play a prominent role for supporting the implementation of an ecosystem approach to fisheries by assessing ecosystem status. Different approaches have been used to build indices on the impact of fishing, in particular for bottom trawling. In this study the Mean Life Span index was used in two areas on historical series of trawl survey data aiming at understanding pros and cons of the use of this index and his applicability in a Mediterranean context. The study was carried out in the Gulf of Castellammare, an area subject to trawl ban since 1990 and in a portion of the Strait of Sicily, an extremely important area for trawl fisheries. The Mean Life Span index was applied at the two Mediterranean historical data-set and the values ranged from 6.1 to 11.01. Its applicability depends on the availability of data on the life cycle of the species, in particular on maximum age. If this data are scanty, its application is poorly indicated. Results obtained in the two study areas showed a slightly increasing trend across years. This could be related to the trawl ban in the Gulf Castellammare and to a decrease of fishing pressure in the Strait of Sicily.

In coastal marine ecosystems coralline algae often create biogenic reefs. These calcareous algal reefs affect their associated invertebrate communities via diurnal oscillations in photosynthesis, respiration and calcification processes. Little is known about how these biogenic reefs function and how they will be affected by climate change. We investigated the winter response of a Mediterranean intertidal biogenic reef, Ellissolandia elongata exposed in the laboratory to reduced pH conditions (i.e. ambient pH-0.3, RCP 8.5) together with an extreme heatwave event (+1.4 degrees C for 15 days). Response variables considered both the algal physiology (calcification and photosynthetic rates) and community structure of the associated invertebrates (at taxonomic and functional level). The combination of a reduced pH with a heatwave event caused Ellisolandia elongata to significantly increase photosynthetic activity. The high variability of calcification that occurred during simulated night time conditions, indicates that there is not a simple, linear relationship between these two and may indicate that it will be resilient to future conditions of climate change. In contrast, the associated fauna were particularly negatively affected by the heatwave event, which impoverished the communities as opportunistic taxa became dominant. Local increases in oxygen and pH driven by the algae can buffer the microhabitat in the algal fronds, thus favouring the survival of small invertebrates.