Unlike the traditional calendar, the official “fishing year” in Iceland is not from January to December but rather from September 1st to August 31st, making the advent of fall the new year for us.
Contributing factors include that in early Spring most fish in Iceland spawn and the larvae gets access to rich phyto- and zooplankton blooms that drift to nursery areas.
Also, fishing during the summer months can be unfavorable because the quality of fish can deteriorate faster than during other times of the year. And on a practical level, many Icelanders working in the fish processing plants take vacation during this time of year.
And so fall, along with land based farmers’ harvests, has become known as high season for Haddock.
Source: Food and Agriculture Organization of the Untied Nations