An investigation of the live bait-shrimp industry of Texas : and the culture and economic potentials for rearing two penaeid species as supplements to that industry

Abstract

Both Penaeus aztecus and P. setiferus were reared in ponds and raceways to determine their culture and economic potentials as supplements to the live bait-shrimp industry of Texas. Growth differences were seen for juvenile P. aztecus stocked at three densities in cages in a greenhouse raceway. After 56 days, the three treatments produced bait-sized 2 shrimp; however, the high density treatment (80/m^2) showed a significantly slower rate of growth and smaller harvest size than the low (20/m^2) and medium (40/m^2) treatments. No difference in survival was seen among the treatments. Growth (0.28-0.34 g /wk), mean harvest size (2.49-3.03 g) and survival (60.3-88.0%) for postlarvae (pl) stocked into six grow-out ponds at experimental densities of 296,400/ha and 592,800/ha were similar after a 63-day culture period. Production was 550-723 and 900-1114 kg/ha for initial stocking densities of 296.4 and 592.8 k/ha, respectively. Growth and final harvest size were, however, different between two pl-stocked nursery ponds (1.5 and 1.95 x 10^6/ha) after 42 days, while production and survival were similar for the non-relicated treatments. P. setiferus was shown to grow at a faster rate and with greater survival than P. aztecus. P. aztecus stage 4 females were captured off the Texas coast during six sourcing cruises in 1983 and 1984. Means of 50 and 45 stage 4 females per trip were collected during April and September cruises, respectively. Spawns, fertilization and hatch rates and overall hatchery production were comparable to those for other penaeid species. P. setiferus were determined to be an acceptable substitute for P. aztecus as a live bait-shrimp by both dealers and fishermen if shading and recirculation of water were provided and if overcrowding was avoided. A simulation model indicated that a 16.2 ha (40 ac) hypothetical farm was an un-profitable venture. While an economically optimum stocking rate (148,200/ha), stocking size (0.25g) and harvest size (5-5.5g) were determined, expenses always exceeded income and the venture was declared insolvent three years after reaching 100% production efficiency. The farm was an economic failure due largely to production and labor costs and low production resulting from the harvest of small shrimp.