High female rate

Tohru tohru.murakami at gmail.com
Wed Apr 6 09:05:00 EST 2005


Hi Christian,

The density of our breeder fish is 3 - 10 / liter. Not sure if it is too
low or okey.


""christian lawrence"" <clawrence at rics.bwh.harvard.edu> wrote in message
news:<d2um70$oot$1 at mercury.rfcgr.mrc.ac.uk>...
> --------------------------------------------------------------------------
> Tohru,
> What are your densities (fish/liter) when you are raising your fish?  
In some cases, zebrafish reared at lower densities often show a female
bias in the sex ratio.  If you are growing the fish up under these
conditions, you may be skewing the sex ratio towards females.  If this
is the case, you may be able to alleviate your problem to some degree by
increasing the density of fish in your rearing tanks.  It may take
longer for the fish to mature, but getting a greater proportion of males
would be worth the wait.
> Sex ratios can also be skewed in one direction or the other if the
strains are very inbred. However, if you are crossing fish from your
facility with fish from other facilities (and presumably different
backgrounds) and you are still seeing a consistent female bias, then it
is likely an
> environmental factor that is causing your sex ratio problems.
> Christian Lawrence
> Brigham and Women's Hospital
> Karp Family Research Laboratories 06-004B
> One Blackfan Circle
> Boston, Massachusetts 02115
> Tel: 617.355.9041
> Fax: 617.355.9064
> -----Original Message-----
> From: owner-zbrafish at hgmp.mrc.ac.uk
> [mailto:owner-zbrafish at hgmp.mrc.ac.uk]On Behalf Of Tohru
> Sent: Tuesday, January 04, 2005 6:37 PM
> To: zbrafish at net.bio.net
> Subject: High female rate
> --------------------------------------------------------------------------
> Hello. We have high female rate from crossings (wild-type x wild-type,
mutant x wild-type, or any; our own crossings and embryos from other
facilities) like 0 - a few / 100 fish that makes it difficult to breed
fish. We raise babies with paramecia, brine shrimp and then flake food.
Any ideas? Thank you. -- Tohru
> ---
> ---

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