Abstract

Aquaculture of procambarid crayfish in Louisiana is based on self-propagating populations, but annual production is often highly variable among geographical locations and from year to year. Variable precipitation, especially during the critical reproductive period when crayfish are in sub-surface burrows, is a likely contributor to inconsistent broodstock survival and reproduction, thus, production variability. The effect of drought on crayfish survival and reproduction has not been thoroughly studied, although, it has been frequently implicated as a major factor affecting crayfish yield and profitability in the past two decades. Therefore, the effects of simulated drought on mature female Procambarus clarkii in burrows were investigated using a system that confined crayfish in self-constructed burrows under controlled but near normal conditions. Artificial precipitation and sub-surface water levels were manipulated to simulate drought or “rainy” weather patterns during the typical burrow occupation period for crayfish in Louisiana. The study, a 2 x 2 factorial arrangement of treatments (factor 1 = precipitation, factor 2 = declining water table), was conducted over two seasons. Survival of females during the 6-month burrow occupation was highly variable (range 39 - 100%) but was weakly associated with treatment effects. Reproduction occurred in 50% or less of the animals within a treatment group by year and was most affected by the restricted precipitation treatment. Overall, the water table access had little effect on reproduction, but restricted precipitation resulted in a 62% reduction in the number of survivors that spawned. Although evidence is provided in this study that would support much of the antidotal observations regarding drought and crayfish production, further research is needed to corroborate these findings and to provide additional information relating to burrow ecology and drought under natural conditions.

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