"Catastrophic" Collapses Of Shellfish Populations In Northern Spain; Galicia Was The World's #2 Shellfish Source

A “catastrophic” collapse in shellfish numbers is being reported by Spanish fishers in Galicia, with some stocks falling by as much as 90% in the space of a few years. Galicia is Europe’s principal source of shellfish and, after China, the world’s biggest producer of mussels, which are farmed in the estuaries.

But figures published by a fishing website this month reveal an alarming decline in cockles and clams, which are collected by hand at low tide, as well as mussels, which are farmed on ropes strung from wooden rafts known as bateas. In 2023 the crop of cockles fell by 80% compared with the previous year, while some varieties of clams fell by 78%. Mussel production last year was the lowest in a quarter of a century, falling from 250,000 tonnes in 2021 to 178,000 last year.

María del Carmen Besada Meis, who heads the San Martiño fishers association in the Ría de Arousa, one of the principal sources of shellfish in the region, believes that climate change is the culprit, thanks in part to the recent torrential rains that have reduced the salinity of the rías. Over the past two years rainfall has been well above the average.

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While Martín-Borregón says there is an urgent need to clean up the rías, she agrees that the key factor is climate change. “The waters of the rías are normally cold and the currents bring a lot of nutrients. With warming seas there are species of shellfish that can’t thrive in warm water,” she says. “This is especially the case with mussels and as the temperatures rise the shellfish industry is moving closer towards collapse.” Another factor that reduces salinity, in addition to heavy rains, is when the dams are opened at low tide, flooding the rías with fresh water, causing massive mortality among bivalves, cockles in particular.

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https://www.theguardian.com/world/2025/jan/28/spanish-fishers-in-galicia-report-catastrophic-collapse-in-shellfish-stocks