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Freshwater fish are fish species that spend some or all of their lives in bodies of fresh water such as rivers, lakes, ponds and inland wetlands, where the salinity is less than 1.05%. These environments differ from marine habitats in many ways, especially the difference in levels of osmolarity .
Freshwater organisms are generally divided into the categories of benthic and pelagic organisms, as these are the two zones of life found in the freshwater biome. Freshwater organism can include invertebrates , insects , fish , amphibians , mammals , birds , aquatic plants , and planktons .
Freshwater habitats in the United States are widely contaminated by the common pesticide atrazine. [29] There is controversy over the degree to which this pesticide harms the endocrine systems of freshwater fish and amphibians. Non-industry-funded researchers consistently report harmful effects while industry-funded researchers consistently ...
The diet of the arapaima consists of fish, crustaceans, fruits, seeds, insects, and small land animals that walk near the shore. [18] The fish is an air breather, using its labyrinth organ, which is rich in blood vessels and opens into the fish's mouth, [19] an advantage in oxygen-deprived water that is often found in the Amazon River.
Freshwater ecosystem Freshwater ecosystems are a subset of Earth's aquatic ecosystems that include the biological communities inhabiting freshwater waterbodies such as lakes, ponds, rivers, streams, springs, bogs, and wetlands. [8] They can be contrasted with marine ecosystems, which have a much higher salinity. Freshwater habitats can be ...
However, some fish show a tremendous ability to effectively osmoregulate across a broad range of salinities; fish with this ability are known as euryhaline species, e.g., salmon. Salmon has been observed to inhabit two utterly disparate environments — marine and fresh water — and it is inherent to adapt to both by bringing in behavioral and ...
Of North American freshwater species, an estimated 48.5% of mussels, 22.8% of gastropods, 32.7% of crayfishes, 25.9% of amphibians, and 21.2% of fish are either endangered or threatened. [24] Extinction rates of many species may increase severely into the next century because of invasive species, loss of keystone species, and species which are ...
In most species, the swim bladder extends to the braincase and plays a role in hearing. Ostariophysi, which includes most freshwater fishes, includes species that have developed some unique adaptations. [5] One is the Weberian apparatus, an arrangement of bones (Weberian ossicles) connecting the swim bladder to the inner ear. This enhances ...