08 April 2008

Keeping them alive

The biggest problem with rearing Marmorkrebs is that the high mortality in the early stages -- before individuals get to about a centimeter or so long. Getting embryos is not a problem. Getting hatchlings is not a problem. Nurturing them through to a moderate sized juvenile is the problem.

I don't know if there is anything that can be done about that, however. Most crustaceans do have a reproductive strategy emphasizing quantity of offspring rather than quality.

This suggests that at least initially, developmental research will probably proceed faster than other types of research that revolves around adult organisms.


Jeep Girl said...

Interesting - I have had no problem rearing them once hatched. Maybe because they are in a very well established aquarium with floating plants (they ate the planted ones - what's left is mondo pearl grass floating on top), driftwood, ornaments, gravel - surfaces for microorganisms and algae for them them eat? Their tank is in a window too. Does the extra light help? Does the extra algae growth help? Green shrimp are reproducing at a high rate in that same tank. Do the marmorkrebs eat any of the tiny green shrimp? If so enough survive that I can't tell, and the adult crays don't seem to harass the adult shrimp.

Zen said...

My suspicion is that habitat complexity matters quite a bit; they do not fare at all well in bare surfaces. Simple and more bare tanks are much more convenient in a lab setting, however.

Wolf said...

In my experience all larvae/juveniles of aquatic animals developed better in a "dirty" tank. Perhaps this might help :

Check this Thesis for Chapter 8 and the literature list:


"Detritus is considered to be an important nutrient source for C. destructor (Mitchell
et al., 1995) and other freshwater crayfish (Lorman and Magnuson, 1978; Momot et
al., 1978; Goddard, 1988; Huner, 1990), particularly during the advanced stages of
development (Goddard, 1988, McClain et al., 1992b). In most cases this conclusion
is based on the visual inspection of foregut samples obtained from wild caught
specimens (e.g., Mason, 1975; Lorman and Magnusson, 1978; Momot et al., 1978;
Growns and Richardson, 1988), from the growth response of animals cultured in
detritus-based environments (e.g., Mills and McCloud, 1983, Mitchell and Collins,
1989; Smallridge, 1992; Geddes and Smallridge, 1993), or from tank-based food
selectivity and nutrient assimilation studies (e.g., Reynolds, 1979; Wiernicki, 1984;
McClain et al., 1992a; Ilheu and Berdardo, 1993; Loya-Javellana et al., 1993)."