mpedersen
(Matt Pedersen)
9/23/13 12:34 AM
I am unable to view the success reference - can any details of that be commented on / included here?
shannpeach
(Shannon Pechauer)
9/23/13 08:58 AM
That particular paper involves developing a protocol for rearing and may not actually be the first paper about successfully rearing. I thought it was a great reference though since they essentially pound out the best rearing conditions.
They tried different temps (25C and 28C), stocking densities (10, 20, 40, and 80 larvae per L), prey densities (newly hatched artemia of 1, 4, 7, and 12mL) and meta conditions. Higher survivorship and shorter larval duration was observed for the 28C temperature, although crabs rearing through at 25C had a significantly wider carapace.
A trend of decreasing survivorship with increasing larval density was noticed, but only significant between the highest and lowest treatment groups. At higher densities the megalopa and crab instars would grab each other during settlement and meta. However, they state that for early rearing high stocking densities of 80/L is possible.
For prey densities, the lowest (1 naup/mL) was the worst after the initial zoeal stages because cannibalistic behavior was noted by megalopa upon Zoea II after 5 DPH. For the other treatments, larvae began meta at 8 DPH. They do state that during early stages (zoeal stages), larvae could likely be reared with lower prey densities, however, further experiments would need to be done to confirm.
The settlement experiments refer to another paper where they describe a larval rearing system. From what I can remember, it is essentially a recirculating system that allows for prey to be flushed when a different size mesh is put in and they use imhoff type cones (I thought I had that paper somewhere, but I can't find it at the moment). In the paper I referenced, once larvae were competent to settle, they moved them to a new system that used PVC rings in a water table (a flat bottom instead of cone shaped is the main difference to note) and found that survivorship was higher in the flat bottom system and the resulting crabs were larger. Also, moving them to system B (the flat bottom) from system A (the cones) allows for juvenile growout and frees the larval system several days earlier. Lastly, megalopae are easier to move and handle than early juvenile crabs so moving them to a suitable growout system before they settle is ideal.
M. forceps does not depend on settlement or metamorphosis cues or specific substrata to achieve high settlement rates.
shannpeach
(Shannon Pechauer)
10/4/13 11:10 AM
I just realized that Mithrax forceps is in the DB already...I swore I looked up "forceps" before I submitted this, but perhaps I just looked at "Mithraculus" species and the Mithrax forceps never popped up. In any case, seems silly to do a classification all over again!
Sorry!
shannpeach
(Shannon Pechauer)
10/4/13 11:10 AM
I just realized that Mithrax forceps is in the DB already...I swore I looked up "forceps" before I submitted this, but perhaps I just looked at "Mithraculus" species and the Mithrax forceps never popped up. In any case, seems silly to do a classification all over again!
Sorry!
aomont
(Anderson Monteiro)
10/15/13 08:15 PM
Hi Shannon ! As you have already realized, we had this species in the database, so I'm closing this request.
We have updated the correct genus and added the extra references. Thank you very much for pointing that info.