Population trends of the fan mussel Pinna nobilis from Portofino MPA (Ligurian Sea, Western Mediterranean Sea) before and after a mass mortality event and a catastrophic storm

Two Pinna nobilis populations thriving inside the borders of the Portofino Marine Protected Area (MPA) (Ligurian Sea, western Mediterranean Sea) were monitored before (2012) and after (September 2018) a dire mass mortality event that, since September 2016, spread through the whole Mediterranean Sea. In Portofino MPA, recorded mortality rates reached values of 91.29% and 43.94% in the two populations. The presence of a Haplosporidium protozoan parasite, considered to be the main cause of the mortality episodes, was confirmed from histological evidence: sporocysts and plasmodia were observed in all the tubules of the digestive glands of the collected specimens. Moreover, a catastrophic storm hit the Ligurian coasts at the end of October 2018, causing considerable damages both below and above the surface; a new survey conducted in November 2018 showed the complete annihilation of the two studied populations, as a probable combination of the continued parasite infections and the mechanical impacts caused by the storm. Finally, in June 2020 the sites were monitored again looking for traces of recovery, but no new specimens were recorded, indicating that P. nobilis became virtually absent from the MPA

A Tool for Practical Integrated Time-Table Design and Vehicle Scheduling in Public Transport Systems

Planning of services and resources for public transport systems is a complex process. In practice the planning is usually decomposed into several stages, where service levels are decided first, while vehicles and drivers are only optimized later on. We describe the new TTD.XT tool, developed by M.A.I.O.R. S.r.l. in collaboration with the University of Pisa, that improves the efficient utilization of expensive resources by simultaneously optimizing timetabling and vehicle scheduling. We quickly present the underlying mathematical model and (math-heuristic) algorithm, and compare the solutions constructed by the tool for real-world bus transport planning instances for three major Italian cities with those produced by the standard sequential decision process; the former are significantly better than the latter both in terms of objective function value and when judged by experts of the field

Optimization of scuba diving activities in a Mediterranean marine protected area based on benthic vulnerability assessment

Scuba diving has become an increasingly popular recreational activity, involving approximately 6 million active divers worldwide.The high frequency of diving can impact the benthic communities of marine protected areas (MPAs), possibly jeopardizing the beneficial effects of protection.The Portofino MPA, in the Ligurian Sea, is one of the main scuba diving destinations in Europe, with up to 40,000 dives per year concentrated along 6.5 km of coast.The vulnerability of megabenthic (i.e. animals larger than 5 cm) communities to scuba diving impacts was evaluated at four different depths at all MPA diving spots with close attention to the fragility of all observed species, their frequency in the transects and the inclination and type of substrates.The most vulnerable spots lie below 30-m depth and are characterized by complex coralligenous biocoenoses rich in erect, fragile carbonatic species.The results allowed scuba diving management within the MPA to be optimized. Two main responses have already been put in place: (i) the promotion of a mandatory course for 'Underwater Environmental Supervisors' directed at local divemasters, instructors and owners of diving centres; and (ii) the proposal for the application of conservation measures to scuba diving activities

Scuba diving impact on the red coral population of the Portofino MPA

Thanks to the analysis of detached red coral (Corallium rubrum, Linnaeus, 1758) colonies found within the coarse sediments present at the base of the MPA Portofino cliffs, the impact of the scuba diving activities has been evaluated and discussed

Cruise tourism: an ecological and economic assessment in the territorial context of Portofino MPA

Tourism and cruise tourism in 3 municipalities along the ligurian coast were studied through emergy analysis. Two municipalities are inside the Portofino MPA. The environmental costs and the economic benefits of tourism activities were assessed in the local territory. Moreover the load imposed to the environment by cruise ship tourism was calculated. Similarities and differences among case studies emerged also depending on different territorial management strategies. Results proved that these activities should be managed integrating them in the local context to reduce or mitigate their impacts in order to progress towards their sustainable manage- ment

Population trends of the fan mussel Pinna nobilis from Portofino MPA (Ligurian Sea, Western Mediterranean Sea) before and after a mass mortality event and a catastrophic storm

Two Pinna nobilis populations thriving inside the borders of the Portofino Marine Protected Area (MPA) (Ligurian Sea, western Mediterranean Sea) were monitored before (2012) and after (September 2018) a dire mass mortality event that, since September 2016, spread through the whole Mediterranean Sea. In Portofino MPA, recorded mortality rates reached values of 91.29% and 43.94% in the two populations. The presence of a Haplosporidium protozoan parasite, considered to be the main cause of the mortality episodes, was confirmed from histological evidence: sporocysts and plasmodia were observed in all the tubules of the digestive glands of the collected specimens. Moreover, a catastrophic storm hit the Ligurian coasts at the end of October 2018, causing considerable damages both below and above the surface; a new survey conducted in November 2018 showed the complete annihilation of the two studied populations, as a probable combination of the continued parasite infections and the mechanical impacts caused by the storm. Finally, in June 2020 the sites were monitored again looking for traces of recovery, but no new specimens were recorded, indicating that P. nobilis became virtually absent from the MPA

On the effects of recreational SCUBA diving on fragile benthic species: The Portofino MPA (NW Mediterranean Sea) case study

The main aims of Marine Protected Areas (MPAs) are the conservation of natural habitats and their biological resources, together with the promotion of an eco-compatible economic fruition. In Mediterranean MPAs, the main threats for hard bottom benthic communities come from fishing and mass tourism, in terms of boating and SCUBA diving. The Portofino MPA (Ligurian Sea, North-western Mediterranean Sea) is one of the top diving destinations in Europe and currently hosts an average of 40,000 dives per year, which are mainly carried out along coralligenous cliffs, a habitat of European Community interest, particularly vulnerable to mechanical damages due to the fragility of its numerous calcified species. The aim of this paper is to evaluate the effects of recreational SCUBA diving on benthic ecosystems characterised by the presence of red coral and other associated fragile species. The impact was assessed through the analysis of the biomasses of target organisms (Corallium rubrum, Leptopsammia pruvoti, Madracis pharensis, and six species of bryozoans) whose fragments were found in the sediments at the base of the cliff. The amounts of these fragments inside the detritus in highly frequented sites were significantly higher than those measured in undisturbed sites, of up to 10 times. Our data suggested a recurrent mechanical action, with also very recent breakages, as demonstrated by the occurrence of living, freshly detached organisms. Red coral and other calcified species may be sensitive also to natural (heavy storms) and human (fishing) mechanical pressures other than diving: the characterization of these impacts in the study sites, however, indicates divers frequentation as the major contributor to the damages inflicted and suggests the need for specific management measures