Salmon changes

[Orleander]

Do salmon start to look like this because they are older or because they are spawning? When do they start getting the hooked nose?

 

[cosmictraveler]

Your salmon is what they call a pink salmon and the one you show is old too and it does look like it is spawning.

Characteristics:
The Pink Salmon, also known as humpback or humpie, is the smallest and the most common of all the North American Pacific Salmon. The Pink Salmon has a light-colored flesh, and a delicate taste, with a low fat content. Pink Salmon generally live 3 years, usually weighing from 3 to 12 pounds.

Habitat:
The Pink Salmon is native to Pacific and arctic coastal waters from the Sacramento River in northern California to the Mackenzie River in Canada; and to the west from the Lena River in Siberia to Korea. Pink Salmon were also introduced into the Great Lakes; this is the only location where the Pink Salmon have been successfully introduced into an entirely fresh water environment.

http://lidophogirlie.blogspot.com/

 

[Orleander]

Uh-huh. But does any of that answer my question??? Do they change because they are spawning? If they are kept in an aquarium do they ever change?

 

[CutsieMarie89]

I might be confusing them with another fish, but I think they change because they get older, by the time the males are of a certain age I think it's 3, their hook nose grows over their mouth and they can't eat anymore and they die. They don't live for very long, especially the males. It was in my Biology book back in 11th grade.

 

[Orleander]

So even ones kept in captivity will change like that? Do they die because they are older or because they spawn?

 

[CutsieMarie89]

So even ones kept in captivity will change like that? Do they die because they are older or because they spawn?

That I don't know (or don't remember if I did know at one time)

 

[cosmictraveler]

I don't know if you could keep a salmon in a small aquarium but they do have large scale fish farms raising salmon for sale. As I said the fish you posted is spawning because of her red color I do believe.

 

[Repo Man]

The hooked nose is part of the physiological changes associated with swimming upstream to spawn. Marine biologists believe the dead adult salmon help create an environment rich in insects and other aquatic creatures that are food for the fry salmon when they hatch.

Also, this:

A University of Colorado at Boulder study of landlocked salmon indicates they possess a genetically programmed "aging clock" timed by reproduction, which may provide insight into human aging and Alzheimer’s disease.....

.....Both salmon and humans exhibit remarkably similar aging symptoms, including brain decay, cardiovascular disease, muscle atrophy, skin lesions and the resorption of internal organs. Laboratory studies of APP and beta-amyloid molecules obtained from salmon brains and from a small piece of brain tissue from a human who died with Alzheimer’s disease showed the molecules "to be very similar if not identical," said Maldonado.

In the study, young, castrated kokanee salmon were shown to live to be 7 years to 9 years old, instead of dying at age 2 or 3 like normal, spawning kokanee salmon, suggesting that salmon have an "aging alarm" timed to go off at reproduction. Massive surges of a stress hormone known as cortisol occur in both reproducing and sterile salmon just prior to the onset of the rapid aging process and subsequent death, Norris said.

http://www.colorado.edu/news/releases/2000/99.html

That is a landlocked species of salmon though.

As salmon go upriver, they deteriorate rapidly. You don't want salmon that have made it too far upstream. They aren't worth the trouble to cook.

 

[Repo Man]

I also thought of a similar example of fish aging. There are tropical fish popular with aquarium enthusiasts called annual killifish. One example is Cynolebias Nigripinnis, which was one I had when I went through my amateur ichthyologist phase as a teenager.

The habitat of these fish are pools and streams that dry up annually. When water returns, the eggs hatch, and the fry mature quickly; they have to, because they have to mate before the pools dry up again, and they die. The eggs survive the dry period, and the cycle repeats itself. The eggs will not hatch if they have not been dry for some period of time. Hobbyists can actually send the eggs to each other by mail.

Because they are genetically programmed to only need to last a year, they are pretty short lived even when in an ideal environment that does not dry out.