This article was featured in Eurofish Magazine 3 2026.
OPMEGA is the association of Galician mussel producers, mainly family-scale operators who breed mussels on floating rafts anchored in the Galician rias. The association was established in 1986 but changed its name to OPMEGA in 1996 and has been recognised as transnational (with a member each in Portugal and Greece) producer organisation OPP-18 since 2022.
Producer organisations (POs) are bodies set up by fishery or aquaculture producers under EU-wide rules to look after the day-to-day management of the activities of their members. Moreover, they steer these activities towards sustainability, promote the products through certification schemes, and manage the supply, marketing, and sales of the production.
Galicia is the source of virtually all Spanish mussels
OPMEGA organises Galician mussel producers to defend producers’ interests, and to promote the Galician origin of the mussels under the Protected Designation of Origin, Galicia Mussel (Mejillón de Galicia). It brings together 579 rafts, 312 members, and 11 delegations distributed in the estuaries of Muros and Noia, Arousa, Pontevedra, Vigo and Greece. Delegations are the local offices that form an intermediary between the association and the producers. Today, annual mussel production in Spain is about 200,000 tonnes of which over 90% comes from Galicia. OPMEGA accounts for some 30,000 tonnes. Galicia is thus the biggest mussel producing area in Europe with some 3,300 rafts in total. Ricardo Herbón González, the president of OPMEGA, explains the PO handles sales and payments, making it the principal economic intermediary between producers and buyers. Its delegations operate as local offices close to the producers and typically each mussel-growing area along the Galician coast will be represented by a delegation. The central office communicates demand, the delegations coordinate with the growers, and the product moves through a system in which individual producers benefit from collective marketing. Galicia’s mussel sector is highly fragmented economically and geographically. Production is spread across the estuaries, and farms vary from very small holdings to larger family businesses with several rafts. Irrespective of the source of the mussels, they are all used for the same products. Traditionally, this is mussels packaged in nets of different sizes. More recently, OPMEGA has introduced a new product made up of mussels that are cleaned, sorted, and packaged fresh in a sealed plastic tray that has a shelf life of about 10 days. Younger people find it easier to deal with this product than, a net with mussels, as the plastic tray can go directly in the microwave. It also offers an alternative to the variety of cooked, such as in cans, mussel products that are available on the market. For decades mussels have been cooked to conserve them and this plastic packaged format is a way of offering something different.
Individualism trumps joining a PO
Individual producers’ deliveries of mussels depend on the number of rafts they own. Payment is transparent and depends on the size of the mussels and the volume of mussels in the different size categories that each producer supplies. OPMEGA has different roles to play reflecting its commercial, political, local, and sectoral activities. The central ambition, Mr Herbón González says, is to secure the maximum value for the mussels produced by members. The sales guarantee is among the main benefits that membership of OPMEGA offers, while another is that the producers are confident that they will receive a fair price for their production and that they will be paid on time. Despite these advantages a far greater volume of mussels is produced and sold outside of OPMEGA than through it, a fact
Mr Herbón González attributes to the independent streak among many producers who feel that they need no help to market and sell their product. Each year OPMEGA releases a list of prices, so from the start of the year producers know the unit price for mussels that meet certain criteria (size, meat content). Producers know what they will receive when they harvest their mussels because they can check the quality and from there work out their earnings. The price generally remains stable from year to year. OPMEGA has tried to create a mechanism that will adjust prices to inflation, but this has not been easy. For producers, this transparency is one of the strongest arguments for membership. OPMEGA’s market work is shaped by the changing habits of consumers. Sales are mainly national, with some customers in Italy and Portugal. The organisation sells to retailers, such as Mercadona (the biggest in Spain with a market share of 26%) and to industrial users such as canning companies. Sales can be under the name of the producer even if the buyer knows that it is sold by OPMEGA, in other cases the product is sold without a brand name.
Changing water temperature and salinity affect production
The environmental dimension of mussel production has a bearing on the activity’s profitability. Mediterranean mussels are filter feeders that filter around 60 litres of water a day, which makes them highly dependent on the conditions in the estuaries. Mr Herbón González identifies changes in salinity as a major concern, especially when increased river input reduces the salt content of the water. This concern is echoed by OPMEGA’s own recent communication on storm impacts in the Arousa estuary. In February 2026, the organisation reported mussel mortality following heavy freshwater inflows caused by storms and said it was gathering data from members before taking the issue to the regional authorities. Another change he has noted is in the influx of fresh cold water from the Atlantic to the estuaries. Due to changes in marine currents these injections of fresh water have also changed. As a result, production has been declining. This year, for example, heavy rains at the start of the year caused production to fall by 30-40 percent due to lower water salinity. While salinity is impossible to mitigate, Mr Herbón González says the organisation is developing an app which will use an AI to gather and analyse data so that it can estimate how much of the production they are likely to lose. With this knowledge producers can prepare themselves rather than being caught unawares and suffering the consequences. One way of mitigating the influx of cold water may be to sink the ropes lower in the water column where the water is colder. But this is a complicated operation and because the water temperature may vary at the same height it would be difficult to get it right. The ideal temperature for growing Mediterranean mussels is between 10 and 20 degrees C. Traditionally, notes Mr Herbón González, water in the Atlantic is between 14 and 15 degrees C while now it has increased to 19-20 degrees C. That said, mussel producers are more fortunate than producers of clams or other bivalves which are less resistant to these changes in temperature.
Education should focus on communities
Generational change is an issue that affects the mussel-producing segment as much as any other segment within fisheries and aquaculture. According to Mr Herbón González the fault lies at least partly in the education system which focuses too little on things that are relevant to the immediate community in which pupils grow up. Food production, for example, fisheries, aquaculture, or terrestrial farming is not given the importance it deserves as the backbone of society. A child living a couple of kilometres from a mussel raft may not know what it is or that it even exists, which he finds very disappointing. Another barrier to younger people joining the profession is that many do not know what they need or how to fulfil the requirements to become a mussel farmer. The challenge is not critical yet because the offspring of mussel farmers are willing to take over, but for new blood to enter the sector, the prospects are bleak. In his personal capacity Mr Herbón González, who is also a producer, practices what he preaches. He has taught his three sons how to swim, where the food on their plates comes from, and how to farm mussels. He feels strongly that teaching kids about the origins of the food they eat contributes ultimately to the wellbeing and dynamism of the community around them.
