Effects of stocking wild and hatchery produced postlarval brown shrimp (P. aztecus) in natural estuarine areas

Although the shrimp harvest has generally increased between 1960 and 1969, landings have fluctuated between years and domestic production has not met the increasing demand. Several methods of increasing domestic production through mariculture are being considered. Among these are intensive culture, extensive culture and stocking of post-larval shrimp in natural areas. This study is aimed at evaluating the potential of stocking natural areas by determining for stocked animals (1) survival and growth, (2) resident time in the nursery area, and (3) the effects of artificial stocking on the density of naturally recruited stocks. The initial evaluation technique involves multiple releases of large numbers of wild and hatchery-reared postlarval brown shrimp along with systematic monitoring of postlarval shrimp populations in the release areas. Three small estuarine bayous (12, 38 and 40 acres; average depth = 2 ft. at m.l.t.) opening into West Galveston Bay comprise the study area. Wild postlarvae are stocked in one bayou and hatchery-reared postlarvae in another. The third bayou is used as a control and not stocked. Post-larval brown' shrimp collected during systematic sampling are counted and measured in an attempt to detect population density changes resulting from stocking and to follow the movement of stocked animals. Observations on growth and survival of caged wild and hatchery-reared postlarvae are accompanying the stocking experiments. (DBO)