The credit crunch has had a positive impact on the sales of one type of fish at least, with Waitrose reporting a 76% year-on-year volume increase in mackerel sales.

Shoppers were choosing mackerel because it cost a third of the price of cod, the supermarket claimed. The key UK mackerel fishing season is getting under way. The winter months are the main fishing period for the species, particularly in Scottish waters.

The fish is sold fresh, canned and frozen, with fresh the biggest UK seller. Consumers have spent £64.3m on it in the past year, followed by canned (£28m) and frozen (just £196,753), according to Seafish. Mackerel is the most valuable fish species for Scottish fishermen, who produce 64,590 tonnes, worth £50.4m each year.

Most mackerel landed in Scotland is processed at a primary level in the region and is then sold on to both UK and overseas companies to produce value-added products. The mackerel fishery in the south west of England is fished quite differently to that in Scotland. Traditional handlines are often used and the mackerel is fished in most months but is best from May to December.