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Fiorentino, F., Badalamenti, F., D’Anna, G., Garofalo, G., Gianguzza, P., Gristina, M., Pipitone, C., Rizzo, P., and Fortibuoni, T. 2008. Changes in spawning-stock structure and recruitment pattern of red mullet, Mullus barbatus, after a trawl ban in the Gulf of Castellammare (central Mediterranean Sea). – ICES Journal of Marine Science, 65: 1175–1183.The increase in biomass of red mullet, Mullus barbatus, in the Gulf of Castellammare (northwestern Sicily, central Mediterranean) after a 14-year trawl ban, prompted us to compare the spawning-stock structure and the recruitment pattern before and after the closure. Datasets obtained from three experimental trawl surveys were available before the ban (April and September 1985; April–May 1986) and four post-ban (September and November 2004; March and May 2005). Spawning-stock biomass increased significantly after the ban. Moreover, females at depths >50 m in the post-ban period were larger than those collected before the ban at the same depth. The recruitment pattern of the population also changed. Notably, recruit numbers increased and recruitment occurs over a broader period. The increase in biomass after the trawl ban seems to be the result of a combination of different processes, mainly associated with the lowering of fishing mortality. A positive trend in sea surface temperature in the area may have played a role too. [ABSTRACT FROM PUBLISHER]

In this paper, species diversity of demersal fish communities was analysed over an area covering about 45,000 km2 of the Italian side of the Strait of Sicily (central Mediterranean). Fish abundance data come from a 10-year series (1994–2003) of experimental bottom trawl surveys carried out within the framework of the international program MEDITS. A simple GIS-based method was proposed to identify areas supporting high or low values of diversity and evaluate their temporal stability. A well-defined spatio-temporal pattern in diversity emerged from the analysis, with some areas of great ecological relevance being identified. Importantly, the greatest diversity within the fish communities was consistently seen at the offshore bank on the western part of the south Sicilian shelf (Adventure Bank). The site also supports high total biomass of demersal resources and shows the presence of species of great concern to fisheries. Results suggest that Adventure Bank represents a priority site for investigating the possibility of innovative management of marine ecosystems and demersal fisheries in offshore zones. [ABSTRACT FROM AUTHOR]

Abstract: This study investigated the nurseries of seven commercially important demersal species of the northern sector of the Strait of Sicily (central Mediterranean): red mullet, European hake, horned octopus, deep-water rose shrimp, greater forkbeard, Norway lobster and giant red shrimp. An eleven-year series of data collected through experimental trawling in the Strait of Sicily during spring and autumn was analyzed. The spatio-temporal persistence of the high-density aggregations (hot spots) of juvenile individuals in their first year of life was investigated to identify habitats that serve as nurseries. The density of recruits within the persistent nurseries was used as a proxy of the unit area contribution of individuals which recruit to the adult population. The spatial distribution patterns of the recruits of most the species were well defined and very stable in the long term. Persistent and potentially highly productive nurseries of European hake, deep-water rose shrimp and greater forkbeard were identified off the southern coast of Sicily. Persistent areas of recruits concentration were also observed for the other species investigated, but their specific potential contribution of individuals to the adult population was not substantial compared to adjacent grounds. The close or overlapped localization of sites which regularly host vulnerable life stages of different exploited species, revealed an area of great ecological significance which probably plays a major role in the dynamics of the fishery resources in the Strait of Sicily. Appropriate spatial protection measures of this area, including marine protected area designation, could complement conventional management approach for ensuring the long-term sustainability of these fisheries and stocks conservation. [Copyright &y& Elsevier]

Experiments have shown that increasing dissolved CO 2 concentrations (i.e. Ocean Acidification, OA) in marine ecosystems may act as nutrient for primary producers (e.g. fleshy algae) or a stressor for calcifying species (e.g., coralline algae, corals, molluscs). For the first time, rapid habitat dominance shifts and altered competitive replacement from a reef-forming to a non-reef-forming biogenic habitat were documented over one-year exposure to low pH/high CO 2 through a transplant experiment off Vulcano Island CO 2 seeps (NE Sicily, Italy). Ocean acidification decreased vermetid reefs complexity via a reduction in the reef-building species density, boosted canopy macroalgae and led to changes in composition, structure and functional diversity of the associated benthic assemblages. OA effects on invertebrate richness and abundance were nonlinear, being maximal at intermediate complexity levels of vermetid reefs and canopy forming algae. Abundance of higher order consumers (e.g. carnivores, suspension feeders) decreased under elevated CO 2 levels. Herbivores were non-linearly related to OA conditions, with increasing competitive release only of minor intertidal grazers (e.g. amphipods) under elevated CO 2 levels. Our results support the dual role of CO 2 (as a stressor and as a resource) in disrupting the state of rocky shore communities, and raise specific concerns about the future of intertidal reef ecosystem under increasing CO 2 emissions. We contribute to inform predictions of the complex and nonlinear community effects of OA on biogenic habitats, but at the same time encourage the use of multiple natural CO 2 gradients in providing quantitative data on changing community responses to long-term CO 2 exposure., (Copyright © 2019 Elsevier B.V. All rights reserved.)