Nilsson, 71, and his friend Torsten Lindström had been expecting to find eels when they went back to check their nets in Morrumsån river in southern Sweden.
The piglets were most likely trying to swim across the river when they became entangled in the nets. But a strong current meant they were unable to extricate themselves and eventually drowned.
“Each boar weighed around 40 kilos. They were probably this year’s young. We had a bloody hard job pulling up the nets,” he told newspaper Smålandsposten.
With two of the nets having been ripped apart, Nilsson supects that a couple of adult boars managed to make good their escape.
The six piglets meanwhile are to be used as fodder for the region’s foxes.