As winter fish?
With the onset of winter in the reservoirs, great changes take place that affect the behavior of underwater inhabitants. Reduces the temperature of the water. Gradually decreasing the light period of the day. Then the waters closed ice cover, on top of it floods the snow – luminosity even stronger. A long 4 months underwater inhabitants exist in conditions of cold, lack of oxygen and obscurity. In the wintering period, the fish sharply reduced the activity almost completely stops the consumption of food, retard growth, decreased heart rate, slow response to stimuli, the rate of metabolism in the body slows down and is supported by the accumulated summer fat reserves.
Different species of fish varies waiting out this difficult period. Many species of heat-loving fish such as bream, carp, tench . in October-November gather in huge flocks and go to wintering holes. Here they spend about 3 months almost without movement, like sardines! Those fish that are at the bottom, even bedsores formed on his belly.
Thus fish of the same type and age and spend the winter together in large clusters. If the hole is small, there are arranged identical individuals! Scientists-ichthyologists explain this sugarcubed the fact that the massive accumulation of fish of the same species and age provides them with optimal conditions for wintering, because the processes of metabolism in the body of fish are less intense than it would be if the fish have wintered alone. In addition, more rational use slime, which fish emit as an insulating means.
But the soma are attached higher up, near the wintering holes – the outputs from the depths, the boundaries of pits and increases in the bottom. This is because in the pit a month later after the formation of the ice cover the oxygen regime changes dramatically for the worse that catfish can’t tolerate it.
As winter predatory fish
Fish predators in wintering holes not hiding. But inhabitants of such pits for some reason do not touch, although he could therefore for the whole winter to secure a well-fed existence. Mostly pike, perch and Zander hunt for those fish that the ice shell above his head uneasy and they do not go on with the usual winter habitats are perch, roach, bleak, verhovka, and ruff .
With the advent of the ice cover changes the behavior of predatory fish. Predatory fish share in relation to the light: so, perch is dusky-day predator, pike – dusky perch – globalsummary.
In early winter under the ice created the darkness, which is “at hand” crepuscular predators. And then they in the early days of the establishment of an ice cover be arranged for victims of the carnage. This excellent predator call “pervalidus”.
But for burbot it is the winter season. Warm summer water depresses it. At temperatures above 15-16°C the eel stops feeding and becomes dormant, hiding in coastal holes, under large rocks or driftwood, and at a temperature of 27°C dies. Only in autumn, when the water in the rivers significantly cools down, he wakes up and begins to rapidly fatten up. Hunting burbot prefer night. Young burbot feed on zooplankton, and employee moving to a “fish diet”. When will burst frosts and rivers covered with a thick layer of ice (in November-December in the North or December to February in the temperate zone), burbot becomes more active and starts to reproduce, limitava their eggs on the rocky bottom areas.
The migration of fish
Some fish of temperate and Arctic latitudes in winter are unwilling to change their habitual lifestyle. They prefer to move in warmer water. The Hamsa dwelling in the sea of Azov, they feed intensively in the summer accumulating fat. With the cooling water as it migrates through the Kerch Strait in the Black sea and wintering there, plunging to a depth of 100-150 m. during the wintering migration of Azov anchovy begins the fishing of this fish. Caspian herring in winter it migrates South, where the water is warmer.
But if the pond is shallow, stagnant and frozen over in the winter? Such lakes exist in the Arctic. Their inhabitants – the common carp and black fish Blackfish with the onset of winter buried in the mud. When such water bodies freeze to the bottom, fish are often frozen into the ice. But their endurance to low temperatures is striking. Even trapped within the ice, the fish don’t die unless you freeze the gills and liquid environment of the body. In the spring when the ponds thaw, the Blackfish comes to life and during the short polar summer time to fatten up and breed.
It happens sometimes.
In Equatorial waters, where never winter, the fish may be active all year round. However, some of them in the winter months, too, the problems begin. Only they are connected, of course, not with coldness, but, on the contrary, with unbearable heat and drought. Some tropical fish buried in the mud and fall asleep. It helps them to endure the heat and associated lack of oxygen.
If carp and Blackfish are the most hardy freshwater fish, a small fish of the genus corpozulia – Cyprinodon macularius (tsiprinodon macularis) living in southern North America, holds the record for maintaining the highest water temperature. She lives and manages not to boil in the hot springs California, where the water temperature is 52°C! For reference: in water with such temperature it is impossible for a long time to hold your hand.