General interest questions

Greg Broadhead gregb at sciborg.uwaterloo.ca
Fri Feb 18 11:03:07 EST 1994


In article <ART.94Feb17150745 at world.std.com>,
Al Thompson <art at world.std.com> wrote:
>In article <1994Feb17.023022.13337 at yuma> arsmith at lamar.ColoState.EDU (Alan Smith) writes:
>
>   In article <2ju5gv$g76 at agate.berkeley.edu> hcorbett at garnet.berkeley.edu () writes:
>   >Why do salmon die after reproduction (also worded as, why can't they 
>   >undergo gametogenesis more than one time in their lives)?
>
>   They never got selected for more than one?  Maybe going up a western American
>   river and breeding takes too much energy for them to be able to go back
>   downstream.  Remember their food scource is in the ocean.
>
>But, the steelhead and sea run cutthroat trout both go up stream and back
>to the ocean many times.
>
>   I seem to remember hearing that atlantic salmon actually do make repeat
>   trips.
>
>Atlantic salmon are trout, not true salmon.
>

	It might have something to do with the length of time it takes to
get to their spawning area, remember that these fishes are undergoing
osmoregulation, which places a great stress on the metabolism of these
fish.  Plust they are swimming upstream, often up waterfalls.  Salmon may
not be as equiped to osmoregulate as a cutthroat trout.

--Greg




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