Lake Of Perch (1981)

[music] >> The lake of perch. Winter. This film is about winter in the lake. But before the winter comes, it's autumn. Down in the lake, the water plants are very dense. And they make a lot of [music] oxygen for the fish. The fish need oxygen [music] to make something out of the food they eat. These are bleaks. And there are some perch. The thing is to eat a lot of food now, so as to get [music] through the winter. >> [music] >> The plants begin to wither away and rot. >> [music] [music] >> These small dots are plankton. Some of them are tiny animals. They disappear. But others are tiny plants, which are always [music] making oxygen for the fish. If we take the temperature [music] in the water, we can see that it's getting colder from 12° [music] to 7° C. Fish are cold-blooded animals, and so they have the same temperature as the water. Here's a frog that's [music] going to hibernate. That's its way of surviving the winter. The carp hibernates, too. It wriggles its way down into the mud and sleeps until spring. The bleaks don't hibernate, but when it becomes cold, they move more slowly and eat less. The perch is still hunting. It doesn't hibernate, and the pike doesn't, either. Now it's really winter. It snows, and ice forms on the water. Down under the ice, it's getting colder, too. Right [music] down to 3°. >> [music] [music] >> The fish that don't hibernate move out to the deepest places in the lake. >> [music] >> It's hard to find something [music] to eat. All through the cold period, there's hardly any life in the fish. >> [music] [music] [music] >> The fisherman has put a branch in the hole to warn others. Even though the water freezes again quickly, the ice will be much thinner just [music] here. The fish are very hungry now. >> [music] >> But what if they're the same size? >> [music] [music] >> It's really hard to find food now. In the late winter, the old and weak [music] ones die. And the rest are tired out after the long months of cold. >> [music] [music] [music] >> At last the ice breaks up. The temperature rises. It gets warmer. Now the spring comes. Down in the lake the fish come to life. >> [music] >> The carp wakes out of his hibernation. And the frog. As the water [music] gets warmer, the fish become warmer, too. And they begin to move more quickly. The light becomes [music] brighter and the bottom of the lake flourishes with plant life. >> [music] [music] >> When it's the height of the long water plants grow up. They're called straight [music] weed, and they form a dense forest under the water. >> [music] [music] [music] >> Now there's real life in the fish again. Here are some bleaks. And here are some young perch. >> [music] [music] >> The bigger perch hunt in the straight weed. >> [music] [music] >> What's that? A snail. [snorts] There's a pike. >> [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] >> Hey.