An interesting observation in the laboratory was the production of eggs and juveniles by a female that was collected in July and kept in isolation. This would suggest that females can maintain viable sperm for an extended period, potentially over 1 year (Reynolds, 2002), or that they will produce viable eggs even if they are not fertilised. Other crayfish have been known to reproduce clonally, for example Orconectes limosus (Buřič et al., 2011) and the marbled crayfish Procambarus fallax (Scholtz et al., 2003). Whether this individual maintained sperm from a previous mating or whether it was parthenogenetic is unknown.
If I were to bet, I would bet on sperm storage, which so many arthropods can do. While the evidence for Orconectes limosus being a facultative parthenogen is quite solid, even that has yet to be replicated. Either way, there seems to be much more work necessary to distinguish these two scenarios.
Rogowski DL, Sitko S, Bonar SA. Optimising control of invasive crayfish using life-history information. Freshwater Biology. in press. http://dx.doi.org/10.1111/fwb.12126