According to the police there were around 70 people involved in the brawl as the two rival groups clashed on Saturday night.
There were reports of punches thrown and kicks dealt out. One 43-year-old Bulgarian man was obliged to seek hospital care after sustaining bruising to the ribs.
Some 30 people were escorted out of town by police and a 33-year-old man was arrested for aggravated assault, but was later released on Monday.
The man was suspected of having kicked the 43-year-old in the head.
The cause of the quarrel has not yet been clarified.
“Now I am speculating. But there is a shortage of berries everywhere and they have not been paid. Thsi can lead to panic and the smallest things can prompt irritation,” said Mikael Hedström at Gävle police to the local Gefle Daglbad daily.
Hedström described the situation as “chaotic” and defended the decision of two police officers in attendance to wait for further reinforcements.
“Sometimes one has to retreat. And if anyone argues that it is not professional, then I beg to differ,” he said.