Effects of Flooding Dates on Population Dynamics in South Carolina Crayfish Ponds

Abstract

Production and population dynamics of Procambarus clarkii and Procambarus acutus acutus were studied in nine 0.1-ha earthen ponds flooded in mid-September, mid-October, and mid-November. Mean forage biomass estimates at flooding were similar among treatments. Mean total length (TL) of the young-of-the-year (YOY) crayfish sampled in November by dip nets from September flooded ponds (36.7 mm TL) was significantly larger (P< 0.05) than the YOY from October (28.5 mm TL) and November (21.8 mm TL) flooded ponds. The 1-2 month growth advantage of the YOY in the September flooded ponds did not persist past November. The dip-netted YOY P. clarkii were significantly larger than the netted YOY P. a. actus from flooding to February; thereafter, P. a. acutus were similar in size or larger than YOY P. clarkii. At the harvest, YOY from the September flooded ponds (77.8 mm TL) were significantly larger than the YOY crayfish harvested from October (72.9 mm TL) and November (73.8 mm TL) flooded ponds. The overall mean TL for both species and cohorts of the crayfish harvested from the September flooded ponds (79.2 mm TL) was also significantly larger than crayfish from the October (75.5 mm TL) and November (73.9 mm TL) flooded ponds. The average size of harvested crayfish varied little during the harvest season. Production over a 40-day harvest season averaged 197.3 kg/ha and was similar among treatments. The proportion of YOY P. clarkii in the dip-net samples from the September flooded ponds was nearly double that observed in ponds flooded later. Also, the harvest from September flooded ponds contained significantly higher percentage of P. clarkii than the October and November flooded ponds.

Key Words:

• White river crayfish
• red swamp crayfish
• Procambarus acutus acutus
• Procambarus clarkii
• crawfish culture
• flooding dates