Spain works to improve clam production

Numerous clam species are cultivated in Spain. The fine clam (Ruditapes decussatus) is abundant in the Balearics, Cantabria, Cataluña, Galicia, Murcia and the Basque Country. The Japanese clam (Ruditapes Philippinarum) is intensively farmed in Galicia, and to a lesser extent in Cataluña and the Basque Country. The woodcock, or slug, clam (Venerupis pullastra) is found in Andalucía, Cataluña, Galicia and the Basque Country. The golden clam (Venerupis aurea) is most common in Andalucía, the Balearics and Galicia. And the blonde, or red, clam (Venerupis rhomboides) is particularly prevalent in Andalucía, Galicia and Murcia.

Of these regions, Galicia dominates Spain’s farmed clam production, representing 35 percent of the country’s output, followed by Andalucía with 10 percent and 5 percent from other regions. Spain’s affection for clams is such that demand far outstrips supply, resulting in the importation of 45 percent of its clams from France and Italy and 5 percent from other countries.

Spain produced 2,127 metric tons of clams valued at EUR 19.7 million (USD 25.4 million) in 2011, down 13.8 percent from 2,468 metric tons in 2010. The reduction in supply had a positive effect on the average price with a 4.8 percent increase to EUR 9.27 (USD 12) per kilogram in 2011 from EUR 8.85 (USD 11.43) per kilogram in 2010.       

A relatively old and mature practice, clam-farming efforts in Spain are currently concentrated on eliminating algae and predator control. Cultivation takes place in farms or installations of natural sand banks where juveniles are planted in deep muddy gravel pits, in which good water currents maximize oxygenation. Juveniles are also fattened in trays suspended above the river bottom, with facilities closed off with anti-predator protective nets. According to managers at Spain’s municipal markets, this cultivation technique produces higher quality clams, which attract higher market prices.

Since adopting a patented mollusk depurification technique called VeiroSistem® in 2002, the Galicia Association of Mollusk Purifying Entrepreneurs substituted the traditional pool depurifying method with stackable, forced water circulation containers. Using this technique, 250 kilograms of clams can be purified at any one time while maintaining oxygenation levels, requiring less surface and fewer storage areas, producing significant savings over the last 10 years in time and water, easier clam transportation, reduced mortality rates and higher production levels.

Cultivation of a virus-resistant clam is currently the subject of a study by Spain’s Superior Council for Scientific Research. Due to conclude in 2014, the research is funded by the European Union and aims to develop new technologies to increase seed production. The initiative is of particular importance to Galicia given its high clam production and economic reliance on the species.