ANTI-JELLYFISH NETS

As part of the activities fulfilled in summer 2014 in the framework of the Med-Jellyrisk Project, several anti-jellyfish nets were installed in Italy, Spain and Tunisia. The aim of this activity was to test the nets in different locations and to develop standardized monitoring protocols.

In Italy, with the support of the Regional Directorate of Land and Environment (ARTA) and the Regional Agency for Environmental Protection in Sicily (ARPA-Sicilia), Med-Jellyrisk installed several anti-jellyfish nets in Lampedusa (1), Favignana (3) , and Ustica (1) islands. The nets differed in size (25, 50, 75, 125 m length) and were adapted to different environmental conditions, from sandy beaches to rocky bottoms or mixed types. Anchoring was made possible using screw anchors (for sandy bottoms) or concrete bricks (for rocky and mixed bottoms). Stakeholders (personnel of marine protected areas, staff of beach resorts) were instructed for managing the nets. In some cases (Ustica, Favignana), it was necessary to remove the nets because of the rough conditions of the sea and to reinstall after the storm. Tourists and bathers were always very positive about the nets. Technical improvements for anchoring are needed and are now under development. In general, it appeared that small-sized nets (up to 75 m) can be well managed by 2-3 persons. Larger nets require increasing efforts (time and personnel) for management. In summer 2015 new installations will be set up in the Aeolian archipelago (Islands of Lipari, Salina, Vulcano), where massive swarms of Pelagia noctiluca severely affect the tourist season from May to July.

In Tunisia during the jellyfish summer campaign 2014, in addition to the Jellysurvey (monitoring program) of 200 Km Marine Coastal Zones along the Tunisian coast, the Med-jellyrisk team organizes the installation of 400 m anti-jellyfish nets allowing holidaymakers to feel safe swimming in a protected area along the beaches of Hammamet and Monastir, two famous touristic zones in Tunisia. Thanks to these protective nets there has been a 100% reduction in Pelagia noctiluca and Rhizostoma pulmo species and an 80% reduction in the Carybdea marsupialis and Olindias phosphorica species.

In Spain, the pilot-test took place in Cala Jondal (Ibiza) where two nets were installed.  The nets were 200m long each and were installed in collaboration with local people belonging to the private enterprises in Cala Jondal and to a private company of Ibiza who were in charge of the contact with the local Administration.

In August 2014 a team from the Marine Science Institute in Barcelona traveled to Ibiza for installation of two nets. The work of the team consisted also  in the generation of monitoring and evaluation protocol which implied working together with private companies,  lifeguards , managers and hoteliers in the area.

After several weeks of work the nets were installed successfully in Cala Jondal and the monitoring program also started. 2014 was a year of few jellyfish arrivals to Ibiza but the nevertheless several other aspects could be evaluated. The efficiency, environmental impact, cost (time and money) of such us mitigation tool was successfully evaluated.

After 4 weeks on the water both nets were damaged by unexpected rough sea.

After the pilot trial the most important considerations are as follow:

-       Areas with frequent rough sea conditions will be probably not adequate for the installation of anti-jellyfish nets.

-       Big barriers can represent a big problem in rough sea conditions. Several hours and several people are needed to extract the nets of the water in case of a bad weather forecast. It was also very difficult to determine and standardize the sea conditions in which the net has to be recovered. More studies are needed. But smaller nets might be recommendable.

-       Clear information about the installation, maintenance and monitoring have to be available for organizations or private enterprises considering the use of this mitigation tool. The cost in term of time and working hours is considerable and need to be added to the cost of the nets itself.

-       An index of cost/benefit has to be developed for different areas. The frequency of jellyfish arrivals is it an important point to consider when deciding the installation of anti-jellyfish nets.

-       The days in which jellyfish arrived, the nets were effective avoiding the entrance of the animals to the safe area.

-       The environmental impact on the sea bottom and on the fish communities of the area is being evaluated.

First MED-JELLYRISK anti-jellyfish net installed in Maltese waters in the summer of 2015

The Physical Oceanography Research Group at the University of Malta coordinated the installation of the first-ever MED-JELLYRISK anti-jellyfish net in Maltese bathing waters in June 2015. Such a net was installed at Pretty Bay in Birzebbuga, enclosing a total sea area of 625m2 and reaching down to a maximum sea depth of 2-2.5m, with the collaboration of the Malta Tourism Authority, Transport Malta, the Birzebbuga local council and Blue Flag Malta. The same net, which has been tailor-made such that it keeps out jellyfish individuals from the cordoned area as well as floating debris and residues, has been monitored regularly by staff from the Physical Oceanography Research Group and their students for its performance and environmental impact and was retrieved at the end of the bathing season in September 2015. The net installed at Birzebbuga was officially inaugurated by Hon. Minister for Transport and Infrastructure Joe Mizzi and by Prof. Alan Deidun.