Fresh fish stores on street corners are disappearing because supermarkets are taking over their turf and convenience is denting demand for the traditional staple.

The number of street corner fish stores has more than halved over the last 20 years. According to statistics from the Ministry of Economy, Industry and Trade, there were 19,709 fish stores across the country in 2007, dropping below the 20,000 mark for the first time, compared with 44,000 in 1988.

Consumers are increasingly choosing to buy fish at supermarkets. A survey by the Japan Fisheries Association found that 77 percent of households bought marine produce from fish sections in supermarkets in fiscal 2007.

The result has been a decline in consumption of horse mackerel, sardines and squid. Imports of tuna and salmon are increasing because their prices are stable and specific amounts can be secured.

But the biggest problem for fish stores is preserving freshness, an official at a major fish store said.

"Fresh fish is perishable and hard to handle. If you increase the proportion of dried marine products, you're bound to lose competitiveness and will be forced to close down your store," the official said.

Vegetables can be sold two to three days after being procured, but fish deteriorates within minutes of being sliced with a knife. How to sell fresh fish with good turnover determines the fate of a fish store.

The long hours can be daunting for fishmongers. Store owners hit the markets early in the morning and work until night. "On top of that, if they can't earn much, no one will replace them. There's no positive factor to encourage growth in the number of stores," an agency official said.

The problem may get worse.

"The mismatch between consumers' desire for very fresh fish and distribution is accelerating people's shift away from fish," the official said.