Question

why do fresh water fishes ecrete dilute urine and marine fishes excrete concentrated urine
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Answer 1

Answer:

hemodialysis The kidneys of freshwater fishes are adapted to excrete large amounts of dilute urine. ... Their kidneys produce small volumes of fluid containing high concentrations of salt. Hence, marine fishes drink large amounts of sea water and excrete small amounts of highly salt- concentrated urine (Figure 1).

Answer 2

Answer:

• Fishes that live in freshwater are hypertonic to their aquatic surroundings. As a result, water enters the body, putting them in constant danger of drowning.
• The gills allow some water to leave the body, but not enough to prevent the persistent threat of waterlogging that these creatures suffer. Freshwater fish's kidneys are designed to expel a lot of diluted pee. Large glomeruli, capillary clusters in the kidneys that filter blood and create urine, are present.
• Specialized gill cells that actively carry ions (mostly sodium chloride) from the water into the body have evolved as a remedy.

• Marine fish with bodily fluids that are isotonic, or having the same concentration of dissolved chemicals as the water, like sharks and dogfish, have little issues with water balance.
• However, dissolved chemicals are less concentrated in the bodily fluids of marine bony fish like red cod, snapper, and sole than in saltwater (they are hypotonic to seawater).
• This indicates that water tends to osmotically move out of their bodies.
• They consume seawater to replace the lost fluids, and they expel extra salt through their gills.

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