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Re: Ten fold increase in reproduction by fish.

Posted: Mon Jun 11, 2018 2:08 am
by Lance Kennedy
Not natural selection, true. But that is purely a matter of semantics. It is selection by humans, which is still evolution.

Small fish currently tend to get released since they are less desirable commercially. Since larger fish are removed from the gene pool, the only ones who breed are the minority of smaller fish that mature sexually early. The next generation is composed of those descended from the small breeders, so the number of small breeders is greater. Since the large breeders get killed, their genes are removed from the gene pool, and their numbers in the new generation is lower. Allowing the large breeders to survive and reproduce would mean a new generation descended mainly from large breeders, and a new generation of fish that grow bigger.

Re: Ten fold increase in reproduction by fish.

Posted: Mon Jun 11, 2018 3:14 am
by bobbo_the_Pragmatist
How do you assume they grow bigger?

Re: Ten fold increase in reproduction by fish.

Posted: Mon Jun 11, 2018 4:23 am
by Matthew Ellard
bobbo_the_Pragmatist wrote:How do you assume they grow bigger?


The Charles Atlas workout schedule? :D
Charles Atlas.jpg

Re: Ten fold increase in reproduction by fish.

Posted: Mon Jun 11, 2018 8:14 am
by bobbo_the_Pragmatist
Matt: the analogy would be that the Bully is the seine net, and the exercise would be not getting caught in the net? And that would be an environmental factor favoring cod who swim alone, or pick up some kind of lateral sensation that correlates to a net drawing closer and they bug out for a time?

My concern is that basically "all" the cod get trapped in the net and the smallest ones not good for the table or canning escape thru the net, BUT ALL THE MEDIUM SIZED FISH....get caught and processed.......so how did "the big fish" not get caught before they were Big Fish and got caught but released by the factory ship? so....the genetic factor favoring Big Fish, just doesn't fit in some way, but I'm not entirely comfortable .......

Any thoughts besides remembering your days at the Beach?

Re: Ten fold increase in reproduction by fish.

Posted: Mon Jun 11, 2018 9:59 pm
by Lance Kennedy
It is selection.

It does not matter whether it is natural selection or human generated selection.

When people eliminate big fish, then the trend is for smaller breeders to survive and pass on their genes. But when this does not happen, bigger fish take over as the major breeders, and pass on their genes, meaning the next generation grow to a larger size.

Re: Ten fold increase in reproduction by fish.

Posted: Tue Jun 12, 2018 1:08 am
by bobbo_the_Pragmatist
What is it when ALL the fish are taken?

Re: Ten fold increase in reproduction by fish.

Posted: Tue Jun 12, 2018 3:51 pm
by landrew
bobbo_the_Pragmatist wrote:What is it when ALL the fish are taken?

The collapse of the cod fishery in the North Atlantic.

Stay tuned for tuna next. Some wealthy industrialist decided to corner the market on tuna by depleting the world supply, so it's no longer cheap like "chicken of the sea;" they want it to be the prime-rib of the sea. Unfortunately the ocean isn't exactly an economic playground. She tends to strike back when least expected.

Re: Ten fold increase in reproduction by fish.

Posted: Wed Jun 13, 2018 3:35 am
by bobbo_the_Pragmatist
Tuna: the same size/fertility issue I assume.

Can we crowd fund a deck mounted cannon for Friends of the Ocean? (madeup......does Green Peace go for species preservation, against Oil drilling is the only thing that comes to mind. Peta: no boats.)

Re: Ten fold increase in reproduction by fish.

Posted: Thu Jun 14, 2018 5:54 am
by Lance Kennedy
There is no "tuna problem". Tuna is not a single species. But one tuna species in real trouble is blue fin tuna. The Japanese love it !

Re: Ten fold increase in reproduction by fish.

Posted: Thu Jun 14, 2018 6:10 am
by bobbo_the_Pragmatist
yep....thats the tuna everyone is talking about.

what do you think would happen to the yellow tail once the blue ones are all taken?

Re: Ten fold increase in reproduction by fish.

Posted: Thu Jun 14, 2018 6:11 am
by bobbo_the_Pragmatist
Cod - Wikipedia
https://en.wikipedia.org/wiki/Cod

Many are members of the family Gadidae; others are members of three related families within the order Gadiformes whose names include the word "cod": the morid cods, Moridae (100 or so species); the eel cods, Muraenolepididae (four species); and the Eucla cod, Euclichthyidae (one species).
‎Rock cod · ‎Atlantic cod · ‎Pacific cod · ‎Cod fisheries