DEVELOPMENT OF A REPLICATED LABORATORY SCALE SYSTEM FOR SHRIMP LARVAL NUTRITION RESEARCH.  

Peter M. Van Wyk, Alonnah K. Creswell, Lucas Jennings, Craig L. Browdy.
 Zeigler Aquaculture Research Center
 Harbor Branch Oceanographic Institution
 5600 North US HWY 1, Fort Pierce, FL 34946
 

The mass cultivation of penaeid larvae has been the foundation for rapid growth of global shrimp farming.  Successful cultivation of shrimp larvae requires careful management of a variety of prepared feeds along with live algae, live or frozen Artemia nauplii and/or live feed replacements. Despite the overwhelming importance of proper nutrition and feed management, limited information is available for hatchery managers on precise nutritional requirements and comparative commercial feed performance by larval stage.

Nutrition research is typically conducted in small scale, highly replicated systems.  Few systems like this exist for shrimp larval nutrition due in part to the complexity and inherent variability of larval culture systems. Highly skilled labor requirements are intensive, more a function of the number of tanks, than tank volume, making operations prohibitively expensive. Because of this, much of the larval nutrition research to date has been run in small or medium scale systems where replication was very low and/or the research systems bore limited resemblance to commercial scale systems. The present research was designed to develop a commercially relevant, controlled, and highly replicated small-scale larval culture system that can be successfully operated by a relatively low number of technicians.

The ZARC larval culture system consists of 64, 18-L LDPE cylindro-conical larval rearing tanks. The larval rearing tanks are mounted on 8 racks. Each rack of 8 tanks has independently controlled lighting which can be adjusted to match desired intensity. Temperature in the tanks is controlled by controlling room temperature. Typically a randomized block experimental design is used, with all treatments represented on each rack of tanks. This allows for statistical compensation for differences in performance related to tank position. With independent aeration, screening and carefully engineered plumbing, racks of tanks are designed for precise and convenient management and water exchange. Seawater from a wellpoint is adjusted to a salinity of 31 ppt, treated with 5 ppm of EDTA, and filtered through activated carbon, 10 micron and 5 micron filter bags and a 180 watt UV sterilizer for 12 hours prior to filling of the LRTs. The temperature of makeup water is closely controlled by circulating the water through a 1-hp heat pump. Software for system and data management has been developed to streamline data collection and management for large numbers of tanks. Macroscopic observations of shrimp larvae and conditions in the larval rearing tanks are recorded tank-side on tablet computers. The data is then uploaded into a computer spreadsheet that precisely adjusts feeding rates based on the conditions in individual tanks. All data are archived for subsequent analysis. Initial experiments demonstrate  growth and survival rates typical of commercial systems. Results are replicable between studies and relatively small differences in performance between diets can be demonstrated statistically.