The effect of stocking density on the reproductive output of hatchery-reared Florida apple snails, Pomacea paludosa
2012
Posch, Helen | Garr, Amber L. | Pierce, Rachael | Davis, Megan
The effect of stocking density on the reproductive output of Florida apple snails was investigated with the goal of developing a captive breeding program that would sustain year-round production and yield a high number of juvenile snails. We examined stocking densities of 50, 100, and 150 snails/m² to determine the threshold at which density negatively affects reproduction. Adult snails were added to tanks in a recirculating aquaculture system at a 1:1 sex ratio and reproductive output was followed for 8weeks. The total number of clutches per tank and the number of eggs per clutch were recorded daily. The number of egg clutches produced in each tank was standardized per female to assess among treatment differences. Once hatched, the juveniles were counted and the percent hatch rates were determined for each clutch. The findings of the study demonstrated that density affected the mean number of clutches laid per female per week with snails in the 50 snails/m² treatment having higher egg production than snails stocked at 100 and 150 snails/m² treatments. Similarly, the number of juveniles produced per female was also higher in the lowest density treatment. There were no significant differences between treatments for egg characteristics (number of eggs per clutch and percent hatch rate). Based on these results, it is recommended that adult snails be stocked at 50 snails/m² to yield optimum egg production per female, attain the highest number of juveniles, and to sustain production for a reliable captive breeding program.
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