Questions about baby brine shrimp

[-o-o-o-kerry-o-o-o-]

Hello :-)
In a few days my babies will be hatching. There are lots of them so I am trying to get prepared in advance...
I have a few questions.
Firstly, is it OK to feed the baby brine shrimp before feeding them to larvae? If so, what is safe for them to eat? Or rather, what is safe for the larvae too?
Secondly, when I am harvesting the eggs how do I avoid the unhatched eggs? I can see the cysts floating on the top of the hatchery, do the other eggs sink to the bottom? Will the larvae die if they eat one of these eggs?
Cheers
Kerry

[Jason R Davis]

Hello


Is it OK to feed the baby brine shrimp before feeding them to larvae?

Yes you can fed them but it has been my experience that it is better to hatch smaller batches and feed them before they themselves need to be fed. The baby brine shrimp are full of the good stuff for about the first 24 hours or so after hatching, this is when they are bright bright orange. I hatch what I can feed for about 4 feedings so two days with morning and night feedings. I use decapsulated eggs or decapsulate them myself to reduce hatch times and the risk of shells killing my larvae.

Secondly, when I am harvesting the eggs how do I avoid the unhatched eggs?

Turn off the air to the hatchery, let everything settle for a few minutes then remove the floating shells or shine a small light in the middle of the hatchery and syphon from that area as the brine shrimp all group up to be by the light, the rest of the room needs to be fairly dark.

I can see the cysts floating on the top of the hatchery, do the other eggs sink to the bottom?

Unhatched eggs do sink to the bottom.

Will the larvae die if they eat one of these eggs?

The shells can kill them but I am pretty sure if they eat a decapsulated egg they will be fine.


Just my experiences, others may have better or different advice.

[Johnny O. Farnen]

Why feed BBS prior to using them as larvae food? I fail to see any valid logic there.

You are not actual feeding the napuli anyway. They do not feed until after the second instar, near the end of the ideal target age for use as caudate larvae food at maximum nutritional value and size for newly hatched caudates..


As the time between hatching from the cysts and the first molt into the second instar is roughly 16 hours dependent on species/strain, temperature and photoperiod ideally one would want to time their artemia hatching accordingly by starting a new hatch every other day. By that time metabolite waste in the water will significantly decrease overall yield, and the napuli are of slightly lower nutritional value as they have burned up all of their stored DHA.

Couple this information with the fact most caudate larvae do not feed for the first 72 hours as they are utilizing "yolk" reserves while allowing their lower digestive system to finish forming in preparation for feeding.


While I have no data to prove it, I feel safe in betting that high rates of larval mortality in the first week after hatching are directly linked to feeding either too large or too much artemia napuli at the wrong time resulting in crazy fast sifts in water quality.

There is a plethora of valid and invalid data on Brine shrimp on the web as this is a common aquaculture staple and scientific model.


To help you in learning more here are some keywords and their basic definitions to help you sort out the bull-dookie from the gold:


Hint, dont use BBS in your search. It is a commonly used misnomer that often leads to invalid data!


Brine shrimp, are properly known as Artemia salina, though even this is a bit off as molecular biology is showing a vast range of diversity. Sometimes they are called fairy shrimp too, though more often I see this term used for their fresh and alkalai counterparts.

napuli- the proper term for early instar arthropods

instar- the time between each molting

molting- shedding of the exoskeleton for a bigger one due to growth more properly called ecdysis

I wish you luck! Be careful when researching these guys though....or you suddenly find you have mason jars and fish bowls filled with other "instant" arthropods.

And then your wife threatens to leave you if she finds one more glass baking dish filled with cladocerans around the house...


I should also add that there is no reason to dump napuli hatches once they get too big for your larvae. You can go ahead and feed them, or better yet, do as I do and ignore the culture save to replace evaporation with distilled water. I have one culture here that is four years old and always has multiple instars and adults swimming around in it. It is really handy to steal some of the adults out of there to feed to larger larvae and adult caudates. It is nothing fancy, just a five gallon bucket in the corner of my critter room.

[-o-o-o-kerry-o-o-o-]

Thank you so much Jason and Johnny. I really appreciate your help. I am starting with a new batch of eggs now, perhaps my others weren't great. And I changed my light source. I had an infrared light bulb going so now have a simple desk lamp. I will look into decapsulated eggs too. I think I read somewhere that I shouldn't use them. Yes I think the Internet has confused me.... I'll let you know how I go.

[trailsofslime]

A freind of mine who studied at the artemia reference center once told me it is best to feed off the naupli within an hour after hatching, after 11 to 16 hours. Nutritional value has significantly decreased (temperature dependant).

If worried about the unhatched cyst you could purchase decaped cyst or look online how to decap them yourself.

[Johnny O. Farnen]

I swear by decaps for ambystomid hatchlings.