Thinking third generation ?

A forum to discuss and learn about propagating corals and other invertebrates as well as captive breeding of marine fish.

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Thinking third generation ?

Postby SeahorseWhisperer_ » August 22nd, 2007, 7:51 pm

So, Smarty Jones delivered little ones on Christmas Eve (What did your fish get you?). One of the fry (Barbaro) is now pregnant.

With his sisters babies.....

I do know that I might be able to get away with this for a generation or two. Anyone have experience with major inbreeding issues? I mean, might I expect future generations to have internal organs on the outside or swim into rocks or hitch upside down?
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Postby jhemdal » March 29th, 2008, 7:50 pm


Well, I'd like to say that I've been thinking in depth about your post since you posted it back in 8/07 and just now have formulated a reply for you, but actually - I just was browsing tonight and saw it a minute ago, and that it was unanswered.
I've been the AZA's studbook keeper for Lake Victorian cichlids since 1994. Many of these endangered fish came through a bottleneck of one pair - that is, all resulting offspring in the breeding program are related - brother and sister. We have some fish now at f8 generation with no outward signs of inbreeding depression. I worry that eventually, there will be major problems (as there would be if they were mammals) but it seems that as long as we don't selectively breed for certain traits (like they do with purebred dogs) the problems will be minimal. I heard that a cancer researcher line-bred platyfish through 50 generations with no issues.
In my opinion, the biggest issue is that the offspring will be selected for domestification. This is GREAT if the intent is to grow fish for aquariums, not so good if you plan to try to release them to the wild (as with our cichlids).
I've heard many people decry captive raised marine fish as being "inbred" as early as f2 or f3 generations, but I really feel that this is not a genetic issue, but a husbandry one - small stature, pale colors, stunted bodies, etc.

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