Many Yangtze fish species have declined drastically and 65 were recognized as threatened in the 2009 Chinese red list. China Ībout 2⁄ 3 of the total freshwater fisheries in China are in the Yangtze Basin. For example, the Bigmouth Buffalo is now the oldest age-validated freshwater fish in the world, and its status urgently needs reevaluation in parts of its endemic range. The number of fish species and subspecies to become endangered has risen from 40 to 61, since 1989. North America Ībout four in ten North American freshwater fish are endangered, according to a pan-North American study, the main cause being human pollution. This increase in local diversity is primarily explained by anthropogenic species introductions that compensate for or even exceed extinctions in most rivers. There is an increasing trend in freshwater fish for local taxonomic, functional, and phylogenetic richness in more than half of the world’s rivers. The protection of 30% of Earth's surfaces by 2030 may encompass freshwater habitat and help protect these threatened species. A global assessment of freshwater fishes estimates an average decline of 83% in populations between 19. In 2021, a group of conservation organizations estimated that one-third of the world's freshwater fish species were at risk of extinction. The critically endangered Mekong giant catfish Common warmwater fish include catfish, largemouth bass, bluegill, crappies, and many other species from the family Centrarchidae. Warmwater fish can survive cold winter temperatures in northern climates, but thrive in warmer water. Warmwater fish species can survive in a wide range of conditions, preferring a water temperature around 80 ☏ (27 ☌). Common coolwater species include muskellunge, northern pike, walleye, and yellow perch. They are found throughout North America except for the southern portions of the United States. Common coldwater fish include brook trout, rainbow trout, and brown trout.Ĭoolwater fish species prefer water temperature between the coldwater and the long warmwater species, around 60 to 80 ☏ (16–27 ☌). In North America, air temperatures that result in sufficiently cold water temperatures are found in the northern United States, Canada, and in the southern United States at high elevation. Coldwater Ĭoldwater fish species survive in the coldest temperatures, preferring a water temperature of 50 to 60 ☏ (10–16 ☌). The water temperature affects the amount of oxygen available as cold water contains more oxygen than warm water. Both eels, anadromous salmoniform fish and the sea lamprey have different tolerances in salinity in different stages of their lives.Ĭlassification in the United States Īmong fishers in the United States, freshwater fish species are usually classified by the water temperature in which they survive. Many species solve this problem by associating different habitats with different stages of life. Species migrating between marine and fresh waters need adaptations for both environments when in salt water they need to keep the bodily salt concentration on a level lower than the surroundings, and vice versa. Some other kinds of fish are, on the contrary, born in salt water, but live most of or parts of their adult lives in fresh water for instance the eels. These are known as anadromous fish, and include, for instance, salmon, trout, sea lamprey and three-spined stickleback. Many species of fish do reproduce in freshwater, but spend most of their adult lives in the sea. Sturgeon are found both in anadromous and fresh water stationary forms
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