Aquaculture Europe 2023

September 18 - 21, 2023


Add To Calendar 19/09/2023 14:00:0019/09/2023 14:15:00Europe/ViennaAquaculture Europe 2023SHORT TERM EFFECTS OF ELEVATED NITRITE AND NITRATE ON PACIFIC WHITE SHRIMP Litopenaeus vannamei SURVIVALSchubert 3The European Aquaculture Societywebmaster@aquaeas.orgfalseDD/MM/YYYYaaVZHLXMfzTRLzDrHmAi181982


Andrew J. Ray*, Leo J. Fleckenstein, Nathan A. Kring, Jill C. Fisk

 Center for Aquaculture and Aquatic Sciences, Kentucky State University, Frankfort, Kentucky, USA.

Animal density in indoor shrimp production is continuing to increase as producers seek to maximize production from their aquaculture systems. Increasing animal density and therefore feeding rates, results in faster accumulation of nitrogenous waste in systems with limited water exchange. Pacific white shrimp (Litopenaeus vannamei ) are considered to be resilient to most forms of nitrogenous waste and have higher tolerances than many other aquatic species. Although shrimp may be tolerant to elevated levels of ammonia, nitrite, or nitrate individually, there is little information on the combined effects of these nitrogenous wastes on shrimp, particularly nitrite and nitrate. This study was  designed to evaluate shrimp survival when subjected to elevated levels of both nitrite and nitrate.

In this experiment 36 64-L tanks were stocked with 10 shrimp each at a salinity of 15 ppt. Three different concentrations of nitrite-N (0, 10,  20 ppm) and four different concentrations of nitrate-N (0, 200, 400, 600 ppm ) were used, resulting in a total of 12 treatments with three replicates each. The treatments were labeled based on the targeted amount of nitrite and nitrate in mg/L: 0/0, 0/200, 0/400, 0/600, 10/0, 10/200, 10/400, 10/600, 20/0, 20/200, 20 /400. 20/600. The experiment was conducted for 11 days, at which point the total number of surviving shrimp were counted.

 When examined individually, nitrite had a significant impact on survival at both the 10  and 20 ppm levels. By itself, nitrate levels of 600 ppm significantly decreased shrimp survival. Furthermore,  the interaction between the two  compounds was found to have a significant negative impact on shrimp survival. Combined levels of nitrite over 15 mg/L and nitrate over 400 mg/L showed mortality rates approaching 50%. This has important implications for shrimp producers, as many producers maintain high levels of nitrate and frequently experience fluctuations in nitrite levels. It seems that the two compounds should not only be considered as individually toxic, but in combination as well.