Fitzek, A.R., Samocha, T.M., Mckee, D.A., Vaughan, D.E.
Abstract:
To evaluate the use of Penaeus duorarum as a candidate for live bait shrimp production in Florida and Texas a study was conducted to assess the reproductive performance of this species in captivity. A description is given on the spawning and larval rearing performance of two captive populations. The first population (mean weight: females - 18 +/- 4.2 g; males - 13 +/- 4.9 g) was collected in March 1996, from the Indian River on the east coast of Florida. The second population (mean weight: females - 15 +/- 4.9 g; males - 8.5 +/- 1.55 g) was purchased in April 1996, from retail bait dealers near Crystal River on the west coast of Florida.
Animals were kept in a semi-closed recirculating system at the maturation facility of the Harbor Branch Oceanographic Institution, Ft. Pierce, F1. All females in both populations were unilaterally ablated before stocking in four round fiberglass tanks (8.6 m dia., and 0.5 m water depth) with black walls. Animals were stocked (1:1 male to female ratio) at a density of 13/m2 and 22/m2 for the first and second populations, respectively. Water quality was maintained through 30-50% daily water exchange and 0.3-0.5 daily tank volume turnover using a rapid sand filter. A reverse photoperiod (11 h light/13 h dark) with water temperature of 25-30 C and salinity of 25-30 ppt was maintained throughout the 125 day trial. Animals were fed fresh frozen food (squid and bloodworms) at 25% of the total estimated biomass per day.
First spawning for the Indian River population was observed 30 days after ablation while the first spawning for the Crystal River population was observed 37 days after ablation. Females as small as 13 g were capable of spawning viable eggs. Spawner size varied between 13 and 26 g. A total of 52 spawns (range, 10,000 to 83,000 nauplii/spawn) were collected from the two populations over the duration of the study. Larvae were fed a combination of the algae Chaetoceros gracilis (150,000-250,000 cells/ml) and Artemia nauplii (0.5-2.5 nauplii/ml). Survival to the PL1 stage varied between 25 and 30%.
(Texas A&M University-Corpus Christi, College of Science & Technology, 6300 Ocean Drive, Corpus Christi, Tx. 78412, USA)
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