Fish Wealth

The migration of fis

1. The relatively small number of fish can move freely between fresh water and pressing, to deposit 
2. their eggs. And called on the urgent water fish that ascend toward fresh water to lay their eggs rising fish include Alollowayv and sea lampreys, fish and silver and most species of salmon and snapper Ahabl. And called on the freshwater fish that spawn in the pressing water fish bearish include eels (European eel) and the North American and some types of fish gobies. And some emerging types of fish from the sea to rivers in the usual, which include large numbers of types Alollowayv and lampreys, salmon and fish silver has kept in fresh water, that is, instead of returning to the natural habitat of the pressing water has become endemic in fresh water, so it can not be for young this fish migrate to the sea after hatching. And explains the section how the fish adapt to changes, why can not most of the fish to move freely between the urgent and fresh water.
3. Ahajrktar types of urgent water fish from one area to the other in the sea, at a particular time of the year. For example, deport several types of mackerel and other species of fish that live in the sea towards the beach to bleaching. Migrate every summer a large number of haddock and some types of cold-water fish from inshore waters to colder water away into the sea, and some of the freshwater fish similar migrations. For example, some types of trout lakes swim heading towards the rivers to spawn. And live some other types of lakes and streams mild fish such as bass and perch near the warm surface during the summer. At the onset of winter, water freezes at the surface, but it stays warm slightly under the ice and then the fish migrate to the bottom and stay there until the return of the warm climate
4. .