For fish, season refers to the period when its fat content is highest. Before spawning, a fish feeds and stores fat; during this period its flesh is fullest, most flavorful, and best suited to cooking. After spawning, it has used up its fat, and the flesh becomes watery and bland. This is why the same fish bought for the same price can be a very different product on the plate if it is bought in the wrong month. Fish bought in the right month is a very different product from fish bought at the wrong time.
A fish’s fat content is not constant throughout the year; it rises during certain months depending on the species, and the texture of the flesh changes noticeably during that period. Fattened fish stays moist on the grill, holds together in the pan, and has a distinctive flavor of its own. Fish that has used up its fat remains watery and lacking in texture, shrinks during cooking, and tastes bland. So the main question to ask at the fish counter is not the price, but which stage the fish is in that month. The price of the same species also falls during this period because the catch is plentiful; in other words, the tastiest and cheapest period often falls in the same month.
A seasonal calendar is established for some fish in Türkiye’s seas. Anchovy is a winter fish and fattens as the weather turns cold. Atlantic bonito and bluefish fill market stalls in the fall; both are at their fullest during their migration. Horse mackerel is also a fall and winter fish. Sardines and red mullet are sought in the summer months, while turbot comes into its prime in the spring. This calendar can shift from year to year because water temperatures and migration timing are not constant; the fish at the counter is the most current guide.
The idea of seasonality largely does not apply to farmed fish. Since farm-raised gilthead seabream and European sea bass are fed under the same conditions year-round, their flesh remains similar throughout the year. This is not a flaw; it is a different product. The same can be said of frozen products. Seasonality matters mainly for wild-caught fish. When the two types of the same fish—farmed and wild—are side by side at the counter, part of the price difference comes from exactly this distinction.
There are also closed fishing seasons; the rules vary by species, location, and date. Ask the seller where the fish came from; conditions for farmed fish, imports, frozen stocks, and origin documents also matter. When choosing fish, you can consider the species that is plentiful that month.
In practice, two habits are useful. First, go to the fish counter with a question rather than a recipe: ask what is good today and choose a dish accordingly. Second, buy the fish that is plentiful; the species that takes up most of the counter is generally both the freshest and the least expensive. Fish that has fattened is suited to the grill and oven, while fish from a lower-fat period is better for steaming and soup. Fish that is out of season can also be used if bought frozen. If you plan to freeze it, fish bought and frozen on the day it is in season gives a better result than fresh fish bought out of season.