Norwegian salmon prices have shifted into reverse after a run of increases in July, leading to what one exporter said is a historic decline.

"It's one of the worst collapses ever," the exporter told IntraFish.

The exporter has seen prices down by as much as NOK 15 (€1.44/$1.69) per kilogram, and is expecting the decline to continue into next week.

Salmon prices for all sizes jumped during the past three weeks, as sellers benefited from numbers that reached NOK 75(€7.20/$8.48)