American red crayfish thrive in Spain, balancing ecology and economy

In 1974, Spain imported two tons of American red crayfish (Procambarus clarkii) from Louisiana for aquaculture.

The crayfish spread rapidly through the Guadalquivir River basin, causing ecological damage and disrupting local wildlife.

Local communities built an economy around harvesting the invasive species, leading to legal disputes.

A compromise now permits regulated harvesting to balance ecological health with economic viability.

Scientists confirm the species is permanently established in the Guadalquivir basin.