Artificial rearing of Cambarellus shufeldtii eggs

[milalic]

One observation (from Crusty on the Crayfishmates forums) that will be of interest.

At least in Australian species, Crayfish eggs apparently aren't firmly attached to the female's pleiopods immediately after spawning. The adhesion takes a few days. She will keep her tail tightly wrapped around the spawn until they become adhered.

I have observed that my cambarellus do the tail wrapping like you mention on the first few days.

-Pedro

[YuccaPatrol]

I did some brief research today and found one paper on the artificial rearing of a Cherax species. Next week I can put it online and make it briefly available to anyone wanting to download it.

I only read the abstract and looked at the photos, but they had very good success with their setup.

Most interesting to me is that this sort of thing sheds some light on the role of parental care of offspring.

[Newjohn]

YuccaPatrol
That will be good information to read. Thank You for giving us the chance.

I have seen, both my Shufeldtii and Patzcuarensis do the Tail Wrap.
I have seen them do it, just after the eggs are on there abdomen and all the way until the eggs are hatched.

John

[Neonshrimp]

One observation (from Crusty on the Crayfishmates forums) that will be of interest.

At least in Australian species, Crayfish eggs apparently aren't firmly attached to the female's pleiopods immediately after spawning. The adhesion takes a few days. She will keep her tail tightly wrapped around the spawn until they become adhered.

I am not sure about New World species however.

Certainly a point of interest in the conversation...

Sincerely,
Paul E. Turley

Hi Paul and all, do you know how the eggs adhere to the female? Is it a biological glue or just a structural change?

Thanks.

[Vera]

There are glands on the uropods (tail fins) called glair glands that excrete the adhesive for the eggs. The female keeps her tail wrapped around the eggs so the adhesive is in the right place.

The white glair glands are only visible on females that are capable of breeding, so it's a good way to know if a young female is old enough to breed.

[YuccaPatrol]

Any update on these? I'd love to see a photo of the eggs over time.

[Mustafa]

Alright...here is another update:



The picture was taken yesterday (Monday). As the embryos develop the eggs are getting clearer and clearer and are turning whiter. I assume the white stuff in the eggs is what the embryos feed on. When they young are about to hatch the eggs should be completely transparent with only the young crays visible.

[Neonshrimp]

Thanks for the update!

[Vera]

Wow! Those are gorgeous! Do you have your method of artificial incubation posted anywhere?

I tried artificial incubation with alleni eggs using an egg tumbler for cichlid eggs, but I was unsuccessful. I would love to have more info on this!

[YuccaPatrol]

As the embryos develop the eggs are getting clearer and clearer and are turning whiter. I assume the white stuff in the eggs is what the embryos feed on.

I think you have this switched up. The eggs start out full of yolk that is dark colored. The clear part is composed of the cells of the developing embryo. When they hatch, the larval stages are mostly clear with only a small amount of dark yolk remaining.

Your photos do show that development is progressing very normally. All of the eggs look good and I am impressed with the potential yield. (Of course, don't count your crays until they hatch, but these look great! )

[Mustafa]

Alright...another update...the first larva has hatched. Hooray! This is turning out to be a successful experiment (knock on wood). I have included two pictures below, one original picture and another one with markings to show where exactly the larva is. Keep in mind that crayfish young/larva are not mobile right after hatching (in contrast to shrimp). They usually cling to the abdomen of the female for a few more days until they get to a mobile developmental stage. Since there is no mother to cling on to, this hatched cray is just lying in the net motionless...but alive.

But first a few comments....

I think you have this switched up. The eggs start out full of yolk that is dark colored. The clear part is composed of the cells of the developing embryo. When they hatch, the larval stages are mostly clear with only a small amount of dark yolk remaining.

Of course you're right. That makes a lot more sense than the "white yolk" getting bigger over time...I should not post when I am dead tired in the middle of the night...LOL. However, at this stage there does not seem to be much, if any, yolk left. As you will see in the pictures below, the white part is the body and the dark part is the head of the larva. There may be a yolk sack still attached to the larva, but without a microscope it's going to be hard to prove. In the egg all the way at the bottom of the picture you see what appear to be two eyes.

Your photos do show that development is progressing very normally. All of the eggs look good and I am impressed with the potential yield. (Of course, don't count your crays until they hatch, but these look great! )

The yield is actually higher than it seems. You always only see part of the eggs in the net as I am focusing as close as it is possible with my macro lens. There are right now about 31 eggs and one hatched larva in the net. In the beginning I thought I had only about 30 eggs...but apparently I had more since about 4-6 eggs fungused and were thrown away.

Here are the pictures..they should be self-explanatory:

[YuccaPatrol]

Mustafa, I hear you about getting a little fuzzy brained late at night. I do that a LOT too.

Here is a photo of one of mine at the same newly hatched stage. I have not gotten one of these under the microscope since I do not want to potentially harm one, but I believe these would be in the larval stage known as a "megalops". You can see the distantly space eye, the crab-body shaped abdomen with remaining yolk, and the tail on the left side of the page.



This is awesome to see your success. I'm happy for you and for your crays.



And here is a silly animated generalized diagram showing a generic decapod megalops stage larva.

[Neonshrimp]

Thanks for the great information and pictures to go with it I am actually learning a lot from this thread alone

[Vera]

That is just so awesome! I would never have thought to just hang them in a net like that close to the sponge filter bubbles. I still prefer letting mothers do their job if possible, but to save so many babies that would have been lost is just so wonderful!

Am I correct in assuming there is no airstone in your sponge filter? I'm wondering if the bubble size would make a difference in the turbulence of the water.

Sorry about the really stupid question above. I somehow missed the first page of this post before.

[pturley]

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