Crayfish Moulting

   

This photograph is from Chris in Germany, there are several more photographs of this process on Enriques website.

Crayfish have exoskeletons, check Enrique's page here for a explanation of this fact. For a Crayfish to grow it is necessary for it to shed it's shell. This happens frequently in the juvenile period. The process is that the crayfish absorbs the calcium in it's outer shell into a unique 'organ' called a gastrolith. This in effect softens the outer shell and the crayfish breaks the old shell and escapes with the new 'limp outer shell, over the next day or two the crayfish is soft and very vulnerable to predators. The crayfish re-absorbs the calcium from the 'gastrolith' and become hard again. Enrique, our crayfish behavior expert has more information on this subject here.
   
 

Also see, Max sheds his shell