Effects of metomidate anaesthesia or transfer to pur sea water on plasma parameters in ammonia-exposed Atlantic salmon (Salmo salar L) in sea water

Abstract

Atlantic salmon (Salmo salar L) postsmolts weighing 150 ± 53 g were exposed to 14-15 mg l(-1) TA-N (total ammonia-N) in sea water in 1 m(3) tanks for 24h. Blood samples were then taken A) immediately after the fish were netted from the exposure tanks and stunned by a blow to the head; B) 2-20 min after the fish were transferred to 15 l of an anaesthetic solution of metomidate in "ammonia-free" sea water; or C) 2-20 min after the fish were transferred to 15 l of "ammonia-free" sea water. Plasma TA-N level was 18% lower in the anaesthetised fish compared to in the fish sampled directly from the exposure tanks (p ≤ 0.05), and accordingly 16% lower in the fish transferred to pure sea water although this difference was not significant (p = 0.07). Plasma glucose level was higher in the fish transferred to pure sea water than in the fish receiving the two other treatments (p ≤ 0.05), but plasma urea, osmolality, Na(+, Cl-, Ca2+ or Mg2+) levels did not vary significantly between the different treatments. Plasma TA-N level increased with time in the fish in the metomidate solution (p ≤ 0.02).

Performance and welfare of Atlantic salmon, Salmo salar L. post‐smolts in recirculating aquaculture systems: Importance of salinity and water velocity

“…The water quality in the three RAS in this experiment were well within the range regarded as safe levels of CO 2 , TAN, NO 2 -N, NH 3 -N, TSS and turbidity for post-smolts in seawater (Knoph, 1995;Thorarensen & Farrell, 2011).…”

Plasma ammonia and urea levels in Atlantic salmon farmed in sea water

“…Even larger variations in plasma urea levels but smaller variations in plasma TA levels were found in the studies on dorsally cannulated rainbow trout of Wood et al (1989) and Wilkie & Wood (1991). We have also measured large variations in plasma ammonia and urea levels in ammonia-exposed or experimental control fish of Atlantic salmon deprived of food for 2-3 days before blood sampling by caudal venipuncture (Knoph, 1995;Knoph & Olsen, 1994;Knoph & Thorud, 1995), both when blood has been sampled after metomidate anaesthesia or after stunning the fish by a blow to the head. The large individual variations in plasma TA and urea levels found in the present study were thus not likely to be due to the feeding of the fish before sampling, the blood sampling site, or the immobilization method used.…”

Nitrogen Runoff from Tunnel Blasted Rocks— a Large‐Scale Test

“…In both the United States (U.S. EPA, 1985) and Canada (CCME, 2010) the environmental authorities have made concentration criteria for total ammonium in freshwater dependent on both temperature and pH, realizing the importance of these factors for the ammonium-ammonia equilibrium and their environmental effect. In water environments, ammonia is particularly toxic to macroinvertebrates and salmonide fish, both being basic elements of a freshwater recipient (Alabaster andLloyd, 1982, Baekken, 2000;Knoph, 1995;Williams et al, 1986). Salmon (Salmo salar) fry may be affected by ammonia concentrations as low as 0.010 mg N/L (Knoph, 1995).…”

“…In water environments, ammonia is particularly toxic to macroinvertebrates and salmonide fish, both being basic elements of a freshwater recipient (Alabaster andLloyd, 1982, Baekken, 2000;Knoph, 1995;Williams et al, 1986). Salmon (Salmo salar) fry may be affected by ammonia concentrations as low as 0.010 mg N/L (Knoph, 1995). In laboratory tests, lethal concentrations of ammonia on salmon fry has been reported to be as low as 31 lg N/L (96-h LC50 concentration) (Knoph, 1995).…”

“…Salmon (Salmo salar) fry may be affected by ammonia concentrations as low as 0.010 mg N/L (Knoph, 1995). In laboratory tests, lethal concentrations of ammonia on salmon fry has been reported to be as low as 31 lg N/L (96-h LC50 concentration) (Knoph, 1995). Hickey and Vickers (1994) reported acute toxic concentrations (96-h EC50) for NH 3 from 0.18 to .0.8 mg N/L for several invertebrate species.…”