Venetian Lagoon Mussel Farming Between Tradition and Innovation An Example of Changes in Perception and Multispecies Relations

In Venetian lagoon, mussels as a food, together with technical innovations and new knowledge for their exploitation, are a recent discovery. In the past, the lagoon’s fishers considered them inedible. The first mussel farming was launched in 1939 and mussels began a new process of rehabilitation. It is the beginning of a new relationship. Mussels turn themselves into delicate animals that need care and fishers develop new interactions with the other non-human components of the environment. A mutual relationship (or inter-agentivity) is created between mussel farmers and mussels, and it brings undeniable advantages to both species.

Stakeholder Perspectives on Blue Mussel Farming to Mitigate Baltic Sea Eutrophication

Here, we present an application of systems thinking to controlling Baltic Sea eutrophication—a wicked environmental problem characterized by multiple stakeholder perspectives and no single, agreed upon solution. The Baltic Sea is one of the most polluted waterbodies in the world. More than 40 years of land-based (linear) measures have failed to adequately control eutrophication, yet internal (circular) measures are rarely used. Farming native blue mussels for nutrient capture has been proposed as one measure for eutrophication control, but the relevant stakeholders disagree as to its environmental, social and economic benefits. Here, we present the views of four Swedish stakeholder groups—academics, entrepreneurs, municipal government employees and representatives of non-governmental organizations (NGOs)—on the sustainability of native blue mussel farming, a circular measure for eutrophication control. Using semi-structured interviews, we elicited stakeholder perspectives on the environmental, economic and social dimensions of blue mussel farming. The interviewees generally agreed that blue mussel farming is not currently economically sustainable, but that it can contribute to the social sustainability of coastal regions. Academics were skeptical of the environmental benefits, claiming that farms could reinforce eutrophication, whereas the remaining stakeholder groups argued for its potential to mitigate eutrophication. In a roundtable discussion conducted one year after the original interviews, all stakeholder groups agreed that blue mussel farming alone will not fix Baltic Sea eutrophication, but can be part of the solution together with land-based measures. All groups also agreed on the need for cautious upscaling, continuous environmental monitoring and constant improvement if blue mussel farms are to be part of a “toolkit” for eutrophication control. Our results highlight the fact that wicked environmental problems can be addressed when multiple stakeholder groups with differing perspectives have the opportunity to achieve consensus through dialog.

Towards Sustainable Management of Mussel Farming through High-Resolution Images and Open Source Software—The Taranto Case Study

This research activity, conducted in collaboration with the Aero-Naval Operations Department of the Guardia di Finanza of Bari as part of the Special Commissioner for urgent measures of reclamation, environmental improvements and redevelopment of Taranto’s measurement, is based on the use of a high-resolution airborne sensor, mounted on board a helicopter to identify and map all in operation and abandoned mussel farming in the first and second inlet of Mar Piccolo. In addition, factors able to compromise the environmental status of the Mar Piccolo ecosystem were also evaluated. The methodological workflow developed lets extract significant individual frames from the captured video tracks, improves images by applying five image processing algorithms, georeferences the individual frames based on flight data, and implements the processed data in a thematic Geographical Information System. All mussel farms, in operation and derelict, all partially submerged and/or water-coated invisible to navigation poles and other elements such as illegal fishing nets and marine litter on the seabed up to about 2 m deep, have been identified and mapped. The creation of an instant, high-precision cartographic representation made it possible to identify the anthropogenic pressures on the Mar Piccolo of Taranto and the necessary actions for better management of the area.

Spatio-Temporal Variability of Anthropogenic and Natural Wrack Accumulations along the Driftline: Marine Litter Overcomes Wrack in the Northern Sandy Beaches of Portugal

Marine litter can end up deposited on sandy beaches and become entangled in the natural wrack, threatening its roles in ecosystems. However, it is currently unknown whether the storage of both artificial and natural accumulations on sandy beaches is correlated. Here, we quantified and compared, by first time, the litter and natural wrack on five sandy beaches in the north of Portugal. Results showed that the amount of marine litter and natural wrack were not correlated. Most of the sandy beaches had more litter than wrack and both artificial and natural accumulations disclosed high spatio-temporal variability. In summer, annual and opportunistic macroalgae dominated the wrack, while the litter was mainly formed by cigarette butts and leftover food. In winter, perennial taxa were more abundant in the wrack and plastics from mussel farming and cotton bud sticks dominated the litter. The macroalga Fucus spp., plastic pieces and materials from fishing were frequent in both periods. This study confirms that, currently, more litter than natural wrack reaches the Northern Portuguese sandy beaches, evidencing the need to take urgent measures against this contamination. Future management measures should consider this spatio-temporal variability to quantify both depositions.