Fish are being multiplied by the thousands in lakes and ponds throughout the world. Lots of these fish are dying because they are fighting for the same resources such as food and shelter. Lots of fish are also being brought from different ponds and lakes and spread disease. They also take bigger fish and different species from other lakes and ponds and they eat the other fish and aquatic wildlife.
Carp have been native to Asia and Europe for hundreds of years. Sometime in the 1970s, the Asian Carp was introduced to the United States to control weed and parasite growth in river systems and aquatic farms. These carp eventually found their way to the Mississippi River. The carp have been making their way up the river into its tributaries and have been found as far up as Minnesota.
The Humboldt Squid is overpopulating the Pacific coats of the U.S. This is good for the Humans living on the West Coast, but not for the Sea Animals. The Humboldt Squid's diet varies from krill and plankton, to small whales and sharks. Food sources are deminishing as the Humbolt Squid population is increasing.
Overpopulated fish can be as big as Whales or Sharks or as small as Minnows or Shad. In Lake Hillsdale in Spring Hill, Kansas, Minnows are not overpopulated anymore because they have been taken in to Marinas across the country for live bait. This is the case for small fish like shad as well. However for the bigger fish, they are fished and eaten which helps get rid of the population like Tuna.