Rivers have been renowned for the variety and quantity of fish that have been found along their course. In the past this has attracted huge numbers of people to live next to them as they have provided a reliable food source to population.
These fresh water fish have given scientists a good indication to the quality of water that is found in the rivers. During the industrial revolution, many rivers became highly polluted as different companies would simply pour their waste waters straight into the rivers. Many fish cannot survive in polluted water, so by counting the numbers of fish in a river gives a good indication to the quality of the water.
Today in the developed world, the most popular fishes are those that provide man with a sport – fishing. Certain game fish see men and women go to great lengths in order to be able to catch a certain fish. This may be in some type of angling contest or simply part of someone’s recreational time.
One of the most famous fresh water fish for anglers is the Salmon which is a specimen of a fish that can survive in both salty and fresh water. The salmon starts its life in high altitude streams before making its way down to the ocean where it remains until it becomes sexually mature.
It will then start a journey to return to the fresh water locations to reproduce after which they die. It is this run with salmon fighting to swim upstream that makes them an attractive challenge for both man and beast to pursue. As well as giving anglers the opportunities to fish for them, they also provide an important food source to animals, such as the bear and birds of prey, waiting in earnest by the river banks for a catch.
Almost as popular as the salmon is the trout. Apart from the rainbow trout, this fish predominantly occupies rivers and fresh water lakes. As well as being delicious to eat, they are a strong fish, which means that the angler is given a good battle when trying to land the fish.
There are other fish that are popular to catch but not necessarily to eat. The pike is a carnivorous fish that roams around lakes and rivers hunting on other fishes. It can grow to a great size and when hooked on a line is capable of testing the most experienced of anglers with the intensity of its fight. The fish looks as attractive as it behaves, yet this does not put off many anglers from trying to catch one.
As popular as pike catching is the carp fishing. The carp can be found in North America, Europe and Asia and can grow to gigantic sizes. It is seen as a food source in Asia, but in Europe it is mainly caught for the sport. There are many varieties with the Koi Carp being used for ornamental purposes and some are worth a great deal of money.
There are thousands of different varieties of fish that occupy rivers. The dominance of one type will depend on the climate and the food source available to them. They have proved to be an important part of the local ecosystem.