The outbreak in Aragon province, 125 miles east of Madrid, was discovered after a farm employee’s wife contracted the virus in May. Her husband and six other farm workers have since tested positive for Covid-19.
Authorities initially ordered that the animals should be isolated. But a few weeks later, after several rounds of testing, they decided to cull the mink, which are farmed for their fur.
As many as 80 per cent of a sample of the animals tested positive.
The company will receive financial compensation for the culling, authorities said.
Coronavirus has proven contagious in several types of mammals including cats and dogs.
Cases of mink with Covid-19 were identified in Denmark, the world’s largest producer, and the Netherlands.
Even though the animals did not show any symptoms, hundreds of thousands were culled to prevent farmers becoming infected.