Farmers in west Alabama raising Pacific white shrimp, Litopenaeus vannamei, in low salinity water have reported higher than usual mortality of shrimp late in the production season. Typically mortality is observed in shrimp larger than 20 g in size and occurs in the final months of culture (August, September, October). Commercial shrimp producers have referred to this poor survival of larger shrimp as "late term mortality". Throughout the last few years of production, this chronic late term mortality has resulted in reduced profits for commercial producers raising shrimp in semi-intensive pond production systems in Alabama and other states. In order to evaluate survival of large shrimp late in the production season, an experiment was carried out in an on-levee tank system installed adjacent to a shrimp production pond on a commercial farm in west Alabama. The tank system consisted of 12, 800-L tanks supplied continuously with low salinity (2 g/L) pond water via a regulated water pump. Aeration was provided to each tank via two air stones and a regenerative blower. Baby Belt automatic feeders were installed to supply feed to each tank with a commercial feed (32% protein) ration divided to provide 4 feedings over a 24-hour period. The tank system was stocked with shrimp (16.1 ± 0.47 g mean initial weight) at densities of 20, 25, 30, and 35 shrimp per tank (3 replicates per treatment). Experimental shrimp were captured by cast net from a production pond on the commercial farm in which the trial was carried out. Throughout the trial shrimp are being sampled every two weeks to track growth rates. Dissolved oxygen and temperature are being monitored daily, while pH, salinity, total ammonia nitrogen, and nitrite nitrogen are being measured weekly. The production trial is currently ongoing and will be harvested in October 2019. Shrimp survival, final weight, yield, and food conversion ratio will be determined at the end of the trial. Results will be used to evaluate survival of large shrimp late in the production season.