BornToBeWild wrote:Perhaps to explain it better...let's go to basic salmon biology 101 Q & A I discovered last night or the night before on the NOAA site.5) Temporary relaxation during the culture phase of selection that otherwise would occur in the wild
Artificial mating disrupts natural patterns of sexual selection. In hatcheries, humans select the adult males and females to mate, not the salmon. Humans have no way of knowing which fish would make the best natural breeders. In addition, selection is relaxed up until the time when juveniles are released from the hatchery (because they don't face the same predation and foraging challenges as wild juvenile fish). Fish raised in hatchery environments face very different pressures than those raised in the wild.
Risks to Wild Populations from Hatchery Fish - Genetic Risks
I gotta get back to work...guy needs to be retired.
BTBW
Since everyone is being really civil to each other, let's continue do so. I have a few questions about your last post where you quoted this:
5) Temporary relaxation during the culture phase of selection that otherwise would occur in the wild
Artificial mating disrupts natural patterns of sexual selection. In hatcheries, humans select the adult males and females to mate, not the salmon. Humans have no way of knowing which fish would make the best natural breeders. In addition, selection is relaxed up until the time when juveniles are released from the hatchery (because they don't face the same predation and foraging challenges as wild juvenile fish). Fish raised in hatchery environments face very different pressures than those raised in the wild.
A)
humans select the adult males and females to mate, not the salmon. Humans have no way of knowing which fish would make the best natural breeders.
1) Well, fish have no way of knowing either! Have you ever set and watched fish spawn before? A hen comes in and picks her nest area, and she lays her eggs and then a male, any male, comes in and tries to fertilize her nest. Then another male make another attempt to do exactly the same thing, then a jack or in the case of steelhead, a resident trout jumps in as quick as lighting and does his thing!
It's simply a matter of who gets there first! The hen doesn't pick "her man", its who get in there first and does his job. True, larger males will chase away smaller males, but those little inferior guys get their shot in! That is also why they use jacks in their brood stocks. So how does the act of a human grabbing a fish out of lets say fifty or a hundred fish a day in a hatchery environment differ that much from more from what happens in the natural wild selection scheme that fish do?
B)
Humans have no way of knowing which fish would make the best natural breeders[/u][/b].
2) The about example is a perfect example that shows that fish don't either! It's how it works! First come…first served!
C)
In addition[/u], selection is relaxed up until the time when juveniles are released from the hatchery (because they don't face the same predation and foraging challenges as wild juvenile fish)
3) not really sure how that statement stands up in the real world of actual science.
"Selection" is a double edged sword. It can and does work both ways. In a hatchery environment, an entire run of fish can be either saved, or killed off. In a wild environment, an entire run of fish can also be eliminated. If you think that I am wrong, there are thousands of fish species that disappeared over time, and most of them were long before man had any effects on them. It's a dirty word, but I am going to say it anyways…evolution!
Species learn to "adapt" or evolution makes the adaptation for them.
It's Christmas Eve and I may have missed a couple things, but lets pick this up when everyone is done with Christmas.
Merry Christmas to all!
