World Aquaculture December 2018

42 DECEMBER 2018 • WORLD AQUACULTURE • WWW.WA S.ORG US Shrimp Production in Ponds The majority of commercially farmed shrimp in the US are produced in semi-intensive ponds, with the states of Texas, Florida, and Alabama leading production. The scale of the US farm-raised shrimp industry is small compared to other countries. The industry has grown little in recent years due to a multitude of factors, including unstable post-larvae supply, high startup and operating costs, competition from lower-priced imports and variable survival and production. Despite challenges facing the US shrimp industry, a handful of farmers have been successfully operating shrimp farms in traditional earthen ponds and producing a high-value niche-market product for US consumers. In the past few years, commercial farmers in Texas, Florida, and Alabama using semi-intensive ponds have reported lower production than had been obtained in previous years. For instance, commercial farmers in Alabama raising shrimp in inland saline waters prior to 2014 consistently reported production of 3,300-5,600 kg/ha. Since 2015, average shrimp production in Alabama has averaged less than 2,500 kg/ha. Due to the humid subtropical climate in the southern US, shrimp farmers using earthen ponds as production units typically raise shrimp fromMay to October when water temperatures are warm and conducive to good shrimp growth. If shrimp are stocked too early or harvested too late, water temperatures less than 20 C can result in poor survival. The vast majority of mortality issues reported by Commercial Demonstration of a Probiotic to Enhance Pacific White Shrimp Production in Inland Ponds of Alabama and Florida Luke A. Roy, David Teichert-Coddington, Susan Laramore, Sunni Dahl, Jesse James, Gregory N. Whitis, Benjamin H. Beck and Craig A. Shoemaker commercial shrimp producers have occurred late in the production season, typically in August, September and October, after shrimp have reached an average weight of 20 g (Fig. 1). These late-term mortality issues are not limited to one farm or state as similar trends have been reported in Texas, Florida and Alabama. To avoid late- termmortality, one commercial producer in Texas has shifted the cropping system to harvest shrimp at 18 g and is producing two crops of smaller shrimp rather than one crop of larger, jumbo-size shrimp. In Alabama and Florida, mortality observed in commercial shrimp production ponds often occurs in conjunction with heavy blooms of certain species of blue green algae. Pseudoanabaena , Oscillatoria and Prymnesium (golden algae) have been identified in commercial ponds on Alabama shrimp farms following mortality events. Cyanobacteria, such as Anabaena and Oscillatoria release toxins as they die and shrimp mortality often occurs concurrent with partial or complete algal mortality. Farmers also suspect that Vibrio may be a causative agent in observed mortality because it has been identified in shrimp tissues sampled during large fall mortality events. Chronic exposure to low levels of Vibrio may weaken the immune system, allowing shrimp to succumb to environmental stressors. US shrimp farmers typically market shrimp fresh to customers that come directly to the farm or to restaurants and retail stores. Some farms also sell larger amounts of shrimp as a frozen processed product to a natural foods market. Most of the niche market clientele FIGURE 1. Mortality has been high in recent years in August, September and October on commercial shrimp farms in Alabama and Florida. FIGURE 2. Aerial view of Greene Prairie Aquafarm, Boligee, Alabama (Photo: Troy Bader).