Atlantic herring is available throughout the year but there are considerable differences in size and fat content. The highest fat content is in June and July at approximately 16-18%.

The fat content gradually declines until fish spawn in September/October. It reduces dramatically to 3-5% by December/January and then it begins increasing again. The largest herring is caught in the summer months (May through August) with sizes ranging from 200-350 gms and 20/30 cm (8-10 inches).

Herring can be graded by machine on board the trawlers, according to the customer's specifications.