Successful conclusion of the Mo.Ri.net Project: ghost nets monitored, surveyed, collected and sent for recycling.
Trawls, lost or abandoned fishing gear, fishing lines, trammel nets, creels. This is, in part, the the sad booty that the sea, in about a year and a half, has returned to Mo.Ri.net “Monitoring, census, removal and recycling of ghost nets” researchers, the result of a partnership made up of ISPRA, PolieCo, the University of Siena, the Marine Protected Area of Asinara Island and Marine Protected Area of Capo Carbonara, created with the aim of removing marine waste, in particular lost or entangled nets or parts of them, previously identified and geolocalised, in two Pilot Areas: Marine Protected Area of the Asinara Park and in the Gulf of Asinara and Marine Protected Area Capo Carbonara in Sardinia.
The project and its results were discussed at the final event in Porto Torres, an exchange of experiences with other projects dealing with the problem of marine waste in Sardinia, to outline new development opportunities in the context of the Circular Economy, because the waste collected if suitable, can be sent to the recycling and valorisation process.
During the first phase of the project, the two protected areas were characterised in terms of biodiversity, with a description of the populations present and the identification of habitats, protected species, valuable areas and areas of conservation importance. At the same time, through the use of Multibeam and ROV (Remotely Operated Vehicle), the number type and density of marine litter for an initial assessment of its impact on the communities present. In addition, microplastic sampling and cetacean biopsies were taken on cetaceans. All sampling was carried out in July and August 2022 in the Marine Protected Area of Isola of Asinara, on board the vessel Vega 1, and in October 2022 in the Marine Protected Area of Villasimius on board the oceanographic vessel Astrea.
Waste fishing campaigns were also implemented. In the Gulf of Asinara an average of 97 objects/km2 with a maximum of 732 objects/km2 but in some creeks (to be precise precision 4 out of 37) no waste was found. The value is low compared to other Italian areas of the Mediterranean, where similar monitoring has been conducted (e.g. in the Gulf of of Venice an average of 567/576 objects/km2 were found in monitoring carried out between 2014 and 2015.
The sampling of different fish species, analysed to assess the ingestion of plastic particles, again showed lower percentages than those observed previously observed in other areas of the Mediterranean on the same species.
The second, and most important, phase was the removal of marine litter. Overall, around 2 tonnes of it was collected. Not only fishing nets or parts of them, but also glass and plastic bottles, cans and bags. A delicate operation that follows specific protocols so as not to be harmful to organisms and habitats.
In addition to the help of the Cagliari Underwater Carabinieri Unit, the contribution of fishermen who collaborated in the project was invaluable. Fishermen who collaborated in the project, providing logistical support and collecting on board of the fishing boats the waste caught in the nets during their fishing activities (an activity known known as fishing for litter). The lost nets, disentangled from the bottom by divers, were then the surface by lifting balloons and hauled up by the fishing boats that offered their support their support.
Unfortunately, the third and final phase, coordinated by PolieCo, which involved managing the waste ashore of the collected material, was not as successful as hoped. The recovered waste showed characteristics of unsuitability for subsequent recycling treatment because the long time of on the bottom resulted in it being colonised by various encrusting organisms, which caused them to lose the technical characteristics suitable for proper recycling. For this reason, the
collected materials took the route of disposal. ISPRA researchers, who constantly monitor the seabed with the help of the ROV, have observed how litter and lost fishing gear interact negatively with the marine environment. The damage is mainly due to the entanglement phenomenon, i.e. the covering, abrasion and/or complete covering of organisms. Nets and lines continuing to perform their fishing function even though they are now lost, can in fact eradicate organisms such as gorgonians and corals, moving along the bottom dragged by currents, or can become a trap for organisms such as fish and crustaceans, which inexorably meet their destruction.