Anaesthesia of farmed fish with special empasis on atlantic cod (Gadus morhua) and atlantic habibut (Hippoglossus hippoglossus)

• Published in: Aquaculture
• Main Author: Zahl, Inger Hilde
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: The University of Bergen 2011
• Subjects: VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497; VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920; Norway; Slaughter; atlantic cod; Atlantic salmon; Gadus morhua; Salmo salar
• Online Access: http://hdl.handle.net/1956/4731

During the life cycle as farmed animals there are numerous situations where fish are subjected to handling and confinement. Netting, weighing, sorting, vaccination, transport and, at the end, slaughter are common events under farming conditions. As research animals fish may also undergo surgical procedures, ranging from tagging, sampling, and small incisions, to larger operations. Under these varying situations treatment with anaesthetic agents might be necessary in order to ensure the welfare of the fish. Anaesthetic protocols for new species that are introduced to research or cultivation are generally based on protocols developed for the more established species. In Norway the anaesthetic protocols for Atlantic cod (Gadus morhua) and Atlantic halibut (Hippoglossus hippoglossus), which were introduced to fish farming in the 1980’s, have thus been based on protocols used for salmonid species. Atlantic salmon (Salmo salar) has been farmed since the 1960’s and is the most important species in Norwegian fish farming. The main objective of the current investigation was to gain more knowledge regarding the effect of anaesthetic agents in farmed fish, with special emphasis on Atlantic cod and Atlantic halibut. Large variations in response to anaesthetic agents exist both between and within fish species. Factors such as body weight, water temperature and acute stress may be important for the response and were studied in the current investigation. The anaesthetic agents benzocaine, metacaine (MS-222), metomidate hydrochloride, isoeugenol, 2- phenoxyethanol, and quinaldine were used. In Atlantic cod and Atlantic halibut the agents were studied with regards to efficacy, assessed as induction and recovery times as well as reaction to handling under anaesthesia. In Atlantic salmon pharmacokinetic properties of the agents were examined. Both in Atlantic cod and Atlantic halibut large differences in efficacy between the different anaesthetic treatments were found. Induction and recovery times varied both in relation to body ...