Title page for ETD etd-05092008-231815


Type of Document Master's Thesis
Author Schuler, Dominic
Author's Email Address dschuler@vt.edu
URN etd-05092008-231815
Title Acute toxicity of ammonia and nitrite to Pacific White Shrimp (Litopenaeus vannamei) at low salinities
Degree Master of Science
Department Environmental Sciences and Engineering
Advisory Committee
Advisor Name Title
Boardman, Gregory D. Committee Chair
Dietrich, Andrea M. Committee Member
Smith, Stephen A. Committee Member
Keywords
  • nitrite
  • ammonia toxicity
  • Litopenaeus vannamei
  • Pacific White Shrimp
Date of Defense 2008-04-30
Availability unrestricted
Abstract
The Pacific white leg shrimp, Litopenaeus vannamei, is a potential species for low

salinity inland aquaculture. Due to several independent variables, such as species, age,

size, salinity and pH, that must be taken into account, there are gaps in the literature

pertaining to the toxicity of ammonia and nitrite to shrimp. This study was conducted to

investigate the individual and combined effects of ammonia and nitrite on L. vannamei

postlarvae (25-45 days old) at 10 ppt salinity, 28 C and a pH of 7.8. The independent

variables were salinity, total ammonia as nitrogen (TAN) and nitrite-N (NO2-N),

separately and combined. The TAN experiments were conducted at 18 and 10 ppt

salinity while the NO2-N test was conducted at 10 ppt salinity. Combined TAN and NO2

tests were also conducted at 10 ppt salinity. The LC50 values for TAN at 18 ppt salinity,

TAN at 10 ppt salinity, and NO2-N at 10 ppt were observed to be 42.92, 39.72 mg/L

(2.26 and 2.09 mg/L unionized ammonia-N), and 153.75 mg/L, respectively. When NO2-

N was adjusted to the LOEC level and TAN concentrations were varied, synergistic

effects were observed, with an LC50 calculated to be 28.2 mg/L TAN (1.49 mg/L

unionized ammonia-N). However, when the ammonia level was adjusted to the LOEC

and nitrite was varied, antagonistic effects were observed with an LC50 calculated to be

163.3 mg/L NO2-N. The results suggest that further investigations into the combined

effects of ammonia and nitrite at varying concentrations and lower salinities will be

important in developing “standard operating procedures” for the shrimp industry.

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  combinedrevised.pdf 6.11 Mb 00:28:17 00:14:32 00:12:43 00:06:21 00:00:32
  SchulerThesis.pdf 6.74 Mb 00:31:11 00:16:02 00:14:02 00:07:01 00:00:35

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