Straw zoeae 9-6-22

[mlakers]

I found a surprise spawn in my straw tank on the evening of the 6th. They'd been in the saltwater pool (filtered) most of the day, so I'd lost quite a few, but still counted around 1,150 when I did a population count on day two. That feels like a good number to start with.

I'm using a brand new kreisel that I've been planning out and building for over a year. It's filtered, and the interior volume of the drum is almost five gallons, so that should help a lot with water quality. So far I like the way it's working--lots to sort out, but that's always true with any newly designed piece of equipment that's been built from scratch.

I'm experimenting with "focused feeding", a method designed by Darcy Madsen at Crab Central Station. I'm really liking how that works. It involves removing the zoeae (drawing them to the light and using a siphon) then feeding them with a pipette directly overhead where they are massed in the smaller container with a mixture of foods (brine shrimp, phytoplankton, zooplankton, marine snow, and spirulina), then removing them after they have feasted, avoiding returning the food (as much possible) back to the kreisel.

We're on day four now and I haven't seen any sheds, so I'm thinking I'll see the first sheds tomorrow. They aren't eating live artemia yet (they catch it but immediately drop it), but I'm hopeful they'll figure that out soon. I much prefer live food for them (less messy and lasts longer).

I've found scientific papers on the zoeae of nine different species, but none on straws, so I will have to learn their larval stages as I go. I'm using the paper on violas as my starting point.

I broke out the microscope today and got a good video. You can watch it at my IG: https://www.instagram.com/p/CiSozsbjWQj/

[ROSIEonFIRE]

Ooo how exciting! Keep us posted!

[aussieJJDude]

It be interesting to see how this all plans out, especially the larval stages. I feel like straws could easily have abbreviated stages, it would certainly make things less time consuming!

[mlakers]

I finally moved three C. perlatus babies to land after more than seven weeks in the water. They do love the saltwater, just like the adults. So far, if my (general) count is correct, they are still surviving. They were raised concurrently with C. lilas (of which I got 76 to land--and I just moved 79 total baby crabs to a 20-tall land tank). I kept the two species separate for as long as I could bear to keep two transition tanks running. After 48 days I finally combined the straws into the lila tank. The straws never ate live artemia (not as megalopa or zoeae) so it was really tricky feeding them. If I get the chance to raise them again, they spend so long as megalopa, I will probably set up a small filtered and heated saltwater tank for the megalopa and just let them decide when they want to be land crabs. AND I will "hurry them up" toward the end, moving them into positions where they have to take a shell and leave the water (like a wave might deposit them on land in the wild). They just never did want to leave the water on their own. By the time I saw them morphing into land hermit crabs and drowning, I only had three megalopa left. I moved those three into the saltwater pool in the land tank and they took shells and walked right out. But did not want to do it on their own volition. Stubborn little crabs.

[Renroc]

How long did they stay as zoeae? What days were shed days and how many sheds did they do? They may well have a different cycle to the others you normally do. Morphing to crabs and drowning was the issue I had with my first attempt. Perhaps making the water a little cooler will encourage them to move to land. Mine developed too quickly in the too warm a water and thus drowned before taking shells.

I move my shelled mega into a shallow pool in the transition tanks and they then move themselves to land.

Aussies don't eat live food as far as I've been able to see even as mega.