Introduction
A key bottleneck of marine aquaculture in Italy has been due to the lack of allocated space. This is recognized to be one of the most relevant constraints to limit the expansion of the mariculture industry (COM 2021/236 final). The process through which space is allocated to marine farms, Maritime Spatial Planning, has been defined by ISPRA and the Ministry of Agriculture through a technical manual (Marino et al 2020). Such process, although not yet mandatory, is applied by competent authorities to help identify Allocated Zones for Aquaculture (AZA), consequently allowing for the culture of specified fish and bivalve species, and the monitoring of environmental impacts within such zones.
The first fish farms cluster in Italy was established by the Municipality of Piombino within the gulf of Follonica, allocating an extensive area to multiple mariculture activities.
The area, as we know it today, has been established through the administrative decision Delibera Giunta comunale di Piombino n. 104 del 17/3/2013, a practice lacking a true scientific-based zoning process. Due to an extensive expansion of aquaculture within this zone from 2009 to 2018, this has created a hotspot of fish and bivalve culture, all one next to the other.
Materials and methods
The whole licensed AZA within the gulf is more than 16 mil m2 wide; allocating 5.8 mil m2 to fish culture and 3.7 mil m2 to bivalve culture. The remaining 7.1 mil m2 were identified by the municipality as safety and transition zones.
The boundaries of the zone run due north-south and east-west. Δϕ 2’, ie 3.7km, Δλ 3.2’, ie 4.5km.
Isobaths run along the coastline (West to South-East), with depths ranging 20 to 35 m. On the Northern part of the AZA the seabed consists of dead mattes of P. oceanica (approx. 20m), whilst more intermediate depths are characterized by a mud and silt composition. The deeper ranges of the seabed are composed of sand and mud.
Hydrodynamic forces guarantee optimal water circulation in the bay; currents are seldom less than 10cm/sec, and with wind driven swell occurring within the 1st, 2nd, and more predominantly 4th quadrant (Fig. 1).
Data on aquaculture facilities, such as number of farms, size, production data etc. were collected having direct field survey with fish and mussel farmers operating in the AZA (Table 1).
Results and discussion
The present study identifies the administrative process and technical decisions which have led to the current allocation and use of marine space within the bay.
Each concession license within the AZA has been classified and analyzed in terms of: distance from ports, bathymetry, interference with fishing and tourism related activities, as well as production potential.
A comparison between actual and potential or desired production scenarios has been carried out to estimate and forecast the potential environmental impact and carrying capacity of the AZA.
Dependent on the production output and site-specific parameters (depth, sediment composition, and hydrodynamic forces) for each farm, an environmental monitoring scheme has been developed in correspondence to the ISPRA, ARPAT, and ASC Guidelines.
References
Marino, G., Petochi, T., Cardia, F. (2020). Assegnazione di Zone Marine per l’Acquacoltura (AZA). Guida Tecnica, 214 p., Documenti Tecnici ISPRA, ISBN: 978-88-448-1014-6