Brine shrimp eggs do not hatch

[mordor]

I got premixed bags from SG Bay Brand and I could not make them hatch. At first I thought temperature is too low but when I mixed salt and eggs I bought separately (I guess different strain they are more reddish) it works in the same enviroment. I just just regular kitchen salt but probably I put much more eggs. I bought this premixed bags half year ago, is it possible that hatching percentage is going down over time?

 

[Eva32181]

Could just be the eggs went bad, or were a bad batch to begin with. I use one teaspoon of reef salt to one liter of water and get lots of bbs after 48 hours.

 

[Neil]

I think Eva is right. The eggs are likely bad. Once you unseal BS eggs, the hatch rate decreases quickly. That is why I started buying smaller containers of eggs. By the time I got half way though a big can, the hatch-rate was getting terrible. Even though I keep the resealed container in the freezer, they still seem to deteriorate. I would think that the premixed bags are worse in this regard.
Neil

 

[jvr]

BS eggs

There could be numerous factors involved. The eggs are old and not stored properly. They may have not been an ideal type of egg to begin with. Salinity may not be ideal for hatching, with a high salinity most eggs will refuse to hatch. Over the last few years the eggs seem to hatch considerably better at lower salinities then what most of the books or instructions state. Keep a light near the hatching container, this helps also. Eggs from different sources hatch differently, a few years ago some Great Salt lake companies were selling Russian & Chinese eggs ( under the pretense they were GSL), these eggs were poor hatching eggs.

I ussually buy my eggs by the 1 lb cans or vacuum sealed pouches , upon receipt they go straight into the freezer. When I use the eggs they are taken from the freezer and put straight into the hatcher.

>>I think Eva is right. The eggs are likely bad. Once you unseal BS eggs,
>>the hatch rate decreases quickly. That is why I started buying smaller
>>containers of eggs. By the time I got half way though a big can, the
>>hatch-rate was getting terrible. Even though I keep the resealed
>>container in the freezer, they still seem to deteriorate.

I must however disagree with Neil on his above comment, I have kept eggs in the freezer for over 5 years and they hatch better every time I use them they are unsealed. Storing them in the freezer has improved my hatches and they do not deteriorate in my opinion. Some newly harvested eggs do better after a few months in the freezer, leading me to believe that they did not receive enough of a diapause at selling point the increased time in the freezer allows them to go through a longer diapause and hatch better. By no means keep your eggs stored at room temperature or in your fish room when opened the humidity will deteriorate them.

I use regular feed grade salt, (inexpensive from farm Coop stores $7 cdn for 100 lbs), tap water and vigerous aeration. Aeration plays a key role, it needs to be vigerous. My jars are 1 gallon pickle jars, these are exposed to light for 12-18 hours while hatching .Most of my shrimp hatch in 12-18 hours at 70 f room temperature. With a low salinity. After hatching I add more salt to keep them viable a few days longer- I ussually get 3-5 days of feeding out of one hatcher.

Hope this helps.

John

 

[Neil]

jvr,
You could well be right. That sounds very plausible. Hatching better after a period of freezing works with some bulbs. Maybe my problem lie in the fact that I transfer a week or 2 worth of eggs to a smaller can and then keep them in the refrig(not freezer) for daily use. Could this potentially lead to degredation of their viability with daily opening?
What brand of eggs are you using and where do you get them? Online?
And when you say low salinity, what are you talking-1.010?
Neil

 

[tjudy]

The reference to light in jvr's post is important. BBS need light to hatch properly. Without light they often get 'shell-stuck' for some reason.

I do a bbs hatching lab with my biology students every Fall as in intro to scientific method. The student who shoose darkness as a variable have significantly less hatching than the control (light). What is really interesting though, is that while the students look at the unhatched cysts under dissecting scopes, the bbs start to hatch out very rapidly... there is a vrey bright light on the scope!

If your experienceing poor hatch rates after 24 hours of bubbling, try placing the the bottle in front of a bright light for a couple hours and see if the hatch rate goes up.

 

[jvr]

Neil,

Keeping them in the fridge with daily opening could degrade them. I have kept them in my fish room for a view days and the humidity degraded my hatch by more than 50% in a matter of several days.

Currently I place the eggs straight from the freezer into the hatching jar, and they hatch fine.

I use and have used several brands, Sanders, Argent, Salt Creek and Brine shrimp Direct, lately I have been buying the breeders specials at brine shrimp direct and they are hatching better than the percentage they have quoted. Their 70% hatch ratio are hatching more like 90% eggs. And they are inexpensive. My salinity is below 1.02 closer to 1.015 but I must state that I've not measured it lately, my hand measures the volume that goes into the jar, the volume I put in is two small handfulls in a one gallon jar. It used to be 4 handfulls several years ago. 4 handfulls measured at 1.032. Not very scientific but it works for me.
John