Why do some salmon die after spawning? What happens to their bodies after laying eggs that makes them die?
817823
Salmon die after spawning due to exhaustion and malnutrition.  As most salmon are sea fish, the environment of the creeks and streams are poisonous to them and they are unable to feed as they swim up stream.  By the time they get to the spawning grounds they have used up their stores of energy and cannot get back to the sea.
686445
they live for up to 48 hours on their quest for the egg.  then they will be passed or absorbed once they die.
532142
Well, this isn't a fruit, but here in the US, it is recommended that pregnant women avoid eating salmon due to the potential mercury/other contaminants that the fish ingest. (can't remember which)
873711
Not quite right.  It is most dense at 4 degrees C.  If it didn't, the water would freeze from the bottom up.  As it approaches 0 degrees, it becomes less dense and rises above the more dense warmer water and freezes on the surface and goes down.  Otherwise, fish would be on top of the ice and die after it froze.
381539
quote from wikipedia\nSalmon flesh is generally orange to red, although there are some examples of white fleshed wild salmon. The natural color of salmon results from carotenoids — astaxanthin and, to a lesser degree, canthaxanthin — in the fish flesh. Wild salmon get these carotenoids from eating krill and other tiny shellfish. Farmed salmon get them in their feed, along with other essential nutrients. Astaxanthin is a potent antioxidant that also stimulates fish nervous systems and improves fertility and growth.\n\nfind out more at\nhttp://en.wikipedia.org/wiki/Salmon
590323
Reproduction System:  Depending on the species some clams are either females or males.  Both the eggs and sperms are released into the water.  Some clams are hermaphroditic which means the clam has both male and female reproductive organs.  In the species that fertilization takes place externally, the zygote develops into a swimming larva, trochophore (Alexander 439).  In some freshwater clams the young is carried inside the female's gills for a period of time.  Reproduction can occur at two different times of the year.  "long term brooders or winter brooders" spawn basically in August to October and carry the young all winter long.  The "short tem brooders or summer brooders" spawn during the summer and the young is carry for a few weeks.  After a certain period of time are discharge from the female mussels and become parasites on fish fins, gills, and external surfaces.  This stage may last up to six weeks (Harris and Gordon 2)
358278
Some are hermaphroditic and self-fertilize their eggs, which they keep in their gills even after hatching until the young bear shells. Others are heterosexual and spew out eggs and sperm which unite and produce independent larvae that swim for a few weeks and then settle on a substrate. See ref.
145599
That depends entirely on the fish species and its age and lifestage.\n\nAs others have pointed out many fish like trout or eels will move from fresh water to salt as a normal part of their life cycle. Many other fish trevel between fresh and salt water at will.\n\nHowever if you take a purely freshwater fish, one that has evolved to live exclusively in fresh water, and you drop it into salt water it will  shrivel up and die.\n\nFish don't have waterproof skins. When you place a freshwater fish in salt water osmosis will draw water out of its body far faster than it can be replaced. The fish will become dehydrated and basically die of thirst.
300045
they isolate the two different strands.  think of it as looking in a lake and seeing a salmon and a bass.  even if you stir up the lake you still only see a salmon and a bass.
55901
The eggs and sperm are reabsorbed by the body if they  can not be used.\n\nLink below will give you all the details.
634205
A human is naturally a little lighter than water so will float naturally.\nImmediately when a person dies his body will begin to get rid of a lot of oxygen, and other gases, primarily from the lungs and the blood stream.  When these gases are expunged from the body, the body will sink.\nAfter a while the remaining gases will begin interacting with the tissues and muscles and chemicals in the body and those gases will swell up, causing the body to float again.
1074437
I found this article on parasites and fish.  Hope it helps.\n\nhttp://www.charkbait.com/article/RAPC2.htm
1062365
no, because fish have gills (breathe on the outside) unlike us we have lungs in the inside.  In my aquarium tank I have a small mouth Bass & Yellow Perch, when i feed my bass minnows he would have three minnows in it's mouth (minnows literally sticking out it's mouth)/ my perch as well.  They will swim around with half a minnow sticking out it's mouth and act like it's no big deal.  You will see this with bluegill they will take the worm and swim around with it hanging out it's mouth.  I just feed my fish (thanks for reminding me) and I took pictures so if you want to see them just e-mail and I'll send it to you.  \n-About the dead smaller fish stuck in it's throat some fish I catch may puke up fish due to exhaustion.  When i go fishing for walleyes and northern pike I've had them cough up fish on me.  I've had bass do the same.  \n-Death? He could have died due to foul hooking (not meaning snagging) but if it hook in the middle or back of the throat can kill any fish especially if it's kept out of the water to long, just cut the line and release.  It doesn't work out all the time.
341778
"Osmoregulation is the control of the levels of water and mineral salts in the blood"\n\nTherefore I say why not in fish?  They have blood and their blood also needs to have it levels regulated so it makes perfect sense. If you do not believe me here ya go :D\n\nWithout osmoregulation fish will die \n\nOsmoregulation is the control of the concentration of body fluids. If a fish is unable to regulate the effects of osmosis it will die. Clearly, osmoregulation is a vital function affecting all aspects of fish health.\n\nOsmosis, diffusion and fish health\n\nIf we look at the structure of the gill or gut under a powerful microscope we would see the tissue that lines these structures, the epithelium, is very thin, usually only one cell thick. Such areas are rich in blood vessels with very thin walls. The combined thickness of epithelium and blood vessels is less than the size of a full stop. The structure and thinness of these areas means that the minute particles whizzing around in the water (and blood) can pass through the epithelium and blood vessels with relative ease; in fact in many cases it is as if there wasn't any barrier at all!
519170
if there is too much oxygen, that will over excite the fish and they can die. That is the case with everything. even if we are exposed to excess oxygen, we can die
9032
Typically, all Pacific Salmon live from 2 to 8 years. Life ends for these salmon after spawning occurs. Sockeye Salmon have a typical life span of 3 to 5 years. Most Sockeye spend 1 to 2 years in fresh water followed by 2 to 3 years in the ocean environment before returning to their parent stream to spawn and die. These fish are referred to in biological terms as being 1-2's, 2-2's or 2-3's. The first digit represents fresh water age and the second is for saltwater age. The Kenai River Sockeye run is mostly comprised of 2-2's and 2-3's. Most indigenous peoples of the West Coast are bathed in culture surrounding this seemingly mystical cycle. The adult salmon give life to the juvenile fish but perish in the process. Their dead bodies, lining the shores and bottoms of rivers, sustain the life of the younger fish and provide a food source for other animals and birds of the land. The young fish enter the ocean and provide for life on the open water. Seals, whales and birds of all sorts depend on these salmon for their lives. The young salmon mature and return as adult salmon to their stream of birth to begin the process all over again. Wild salmon are as much a heritage and part of our culture as they are a food source.
1080986
I can't say with any degree of certainty that fish are completely unphased by this experience, but for the most part the holes you make in their mouths by practicising "catch & release" will heal.  They will not affect the fishes ability to eat.  Whether a fish gets over the stress is hard to say!\n\nJust be sure to hold any fish you re-release under the water for a bit, moving it back & forth to get water running over its gills again. \n\nFish have very rudimentary nervous systems, so do not really experience "pain" the way a chicken or a gerbil might.