[Killietalk] Re: Hatching BBS eggs

[Brian Watters <Brian_Watters at uregina.ca>]

Charles Harrison wrote:

> 
> Many of us reuse the saline hatching solution over and over for 
> several hatches. I replace mine after three to 4 days of use, I just 
> dump in another teaspoon of eggs in the mornings into yesterday's 
> solution after I syphon out the hatch from the eggs of the day before.
>

I do the same, except that I re-use the saline hatching solution for 
about 3 weeks before remaking it (that is not an exaggeration and 
sometimes it will be longer; for example, the solution I am using 
presently was made up when I returned from Europe on 1st September). I
always use marine salt and I always get outstanding hatches. Marine 
salt is relatively expensive but since I only remake the solutions 
every 3 weeks or so, it is no big deal. The containers I use are 
one-liter round-bottom boiling flasks (as used in laboratories) with 
very vigorous aeration and connected in series. I harvest BBS twice a
day on a 36 hour cycle. I hatch between a half to three-quarter of a
teaspoonful of eggs in each container. Because of the aeration, there 
is some loss of water from the solution due to evaporation but I make 
this up every week or so by simply adding a small amount of tap water 
to each flask (I don't bother to add more salt). As the solution ages 
and becomes more "soupy" I do in fact get a better and quicker 
separation of the egg shell and BBS. Every time I harvest the BBS (by 
siphoning all the solution from a particular flask through a fine-mesh 
net) I wash out the flask to remove any egg shells or unhatched cysts. 
I always siphon out all the solution and, therefore, all the BBS 
from each flask at the end of its hatching cycle. But then, as 
mentioned, I pour the same solution back into the flask for the next 
cycle. I rinse the BBS in fresh tapwater before feeding to the fish.

Personally, I think the issue of bacteria build-up as a result of 
re-using the brine solution is way overstated.

I never measure the SG of the solution because I don't think it is 
critical. I simply add two tablespoons of marine salt to a bit less 
than one liter of water. I use tap water but I have also used RO water 
with no noticeable difference.

My unopened cans of BS eggs are stored in a freezer and what I am using
presently have been in the freezer for about 8 years. The hatches could
not be better. When I open a can I transfer the eggs to a glass bottle 
with a screw cap and store that in the same refrigerator that I use for
my white worms - so the temperature is about 55-60 F. A smaller volume 
of eggs is contained in a plastic bottle (not sealed) and kept in my 
fish-room for daily use.
__________________________________________________
Brian R. Watters
Professor
Department of Geology
University of Regina
Regina, Sask. S4S 0A2, Canada
Tel: (306) 585-4663; Fax: (306) 585-5433
E-mail: Brian_Watters at uregina.ca

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