High female rate

Tue Apr 5 06:04:00 EST 2005



Are you using non-flowing water egg incubation such as in static dishes? 
Is your system a new system with new tubing (thinking of a problem I had
with some copopods several decades ago)?

We have found that in flowing water hatching systems, we have no sex ratio
problems.  We also haven't seen a density effect, but we have very high
performance filter systems and any of the chemicals that the fish use to
determine the density would be removed.  Visual density data is useless to
a schooling fish -- visual density is always high.

The densities of most research labs are considered low by commercial
standards.  Spawning at 10/liter, larva up to 5/cm2, growout and
maturation at 50 to 100/l, holding at up to 300/liter are our standards.

At the larval stage, the density per unit area (not volume) seems to be a
relevant variable.  They seem to need space between the larva and are
attracted to the surface in a deep tank.

I think that the sex ratio problem is an egg/egg interaction problem in
static systems.


Dallas E. Weaver, Ph.D.
Scientific Hatcheries
5542 Engineer Dr.
Huntington Beach, Ca 92649
deweaver at surfcity.net

> -----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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