Globally, aquaculture productions continue to increase, and will soon surpass even the production of capture fisheries, which have reached the limit. In 2020, g lobal total production of marine ecosystems was estimated at 178 million tons, of which 90 million tons (51%) from capture fisheries and the remaining 88 million tons (49%) from aquaculture activities. Therefore, aquaculture continues to grow faster than the other main food production sectors.
In general , abalone, arkshells, clams, conchs, cockles, mussels, oysters, pectens, scallops, winkles, and aquatic plants production alone, accounting for almost 31% (approx. 54 million tons ) of the total global productions. Specifically, non− fed species currently account for about half of aquaculture productions and offer a potentially significant contribution to the sustainable growth of the global aquatic food supply.
Shellfish farming alone accounts for a large portion of global productions; reaching about 54 million tons of live weight in 2020. The main productions are mainly attributable to the families Mytilidae, Veneridae, and Ostreidae. Coastal areas and wetlands devoted to the production of these important low-cost protein sources are at risk of impact due to climate change. Moreover, the response of these fragile ecosystems is highly dependent on both the magnitude of change and their physical characteristics.
Today, most of the bivalve molluscs consumed are farmed, produced in a number of European countries, North America, China and Chile. The European Union, the United States of America, China, and the Republic of Korea account for the bulk of import demand. Demand for bivalves has remained relatively steady over time, and the species have benefited from a positive perception among consumers as a healthy and sustainable food option. In 2020, global exports of bivalve molluscs totalled USD 4.3 billion, representing around 2.8 percent of the value of global exports of aquatic products.
This preliminary study aims to highlight globally, and then focus on the Mediterranean basin, what are the productions related to the main species of bivalve molluscs reared, the trade and food balances, also highlighting what are the trends and will be the future challenges of these sustainable extensive aquaculture practices.