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4. Pre-Slaughter Stunning of Farmed Atlantic Halibut in CO2-Saturated Seawater : Assessment of Unconsciousness by Electroencephalography (EEG)

Author

Rucinque, Daniel Santiago, van de Vis, Hans, Reimert, Henny, Roth, Bjørn, Foss, Atle, Taconeli, Cesar Augusto, Gerritzen, Marien, Rucinque, Daniel Santiago, van de Vis, Hans, Reimert, Henny, Roth, Bjørn, Foss, Atle, Taconeli, Cesar Augusto, and Gerritzen, Marien

Abstract

As fish welfare becomes a growing concern, it is important to ensure humane treatment during slaughter. This study aimed to assess the onset of unconsciousness in Atlantic halibut immersed in CO2-saturated seawater through electroencephalography (EEG). Of the 29 fish studied, 10 exhibited escape attempts, indicating aversion to CO2-saturated water despite its oxygenation. EEG signals showed four distinct phases: transitional, excitation (high amplitude–high frequency), suppressed, and iso-electric phases. The onset of the suppressed phase, indicative of unconsciousness, occurred on average 258.8 ± 46.2 s after immersion. The spectral analysis of the EEG signals showed a progressive decrease in median frequency, spectral edge frequency, and high frequency contribution, which corresponded to the gradual loss of consciousness. The study concludes that CO2-saturated water is not recommended for pre-slaughter handling of halibut due to the extended time required for the onset of unconsciousness and the observed aversive behaviour. Ensuring humane treatment during slaughter is important for addressing public concern and safeguarding fish welfare in all stages of production.

Published
2023

10. Pre-Slaughter Stunning of Farmed Atlantic Halibut in CO 2 -Saturated Seawater: Assessment of Unconsciousness by Electroencephalography (EEG).

Author

Rucinque, Daniel Santiago, van de Vis, Hans, Reimert, Henny, Roth, Bjørn, Foss, Atle, Taconeli, Cesar Augusto, and Gerritzen, Marien

Subjects
LOSS of consciousness, CARBON dioxide, ELECTROENCEPHALOGRAPHY, SEAWATER, ANIMAL health
Abstract

Simple Summary: The World Organization for Animal Health recommends the use of stunning methods before the slaughter of farmed fish destined for human consumption. The use of carbon dioxide (CO2) is not recommended by the World Organisation for Animal Health for the stunning of farmed fish at pre-slaughter. However, its use continues to be common in the world. CO2 stimulates chemoreceptors, causing aversion and escape attempts when fish are immersed in CO2-saturated water. The use of CO2 in seawater with oxygenated water is allowed for pre-slaughter of halibut in Norway. Hence, there are no studies assessing loss of consciousness in halibut exposed to this stunning method. The best approach to determine unconsciousness is by measuring brain electrical activity through EEG. As fish welfare becomes a growing concern, it is important to ensure humane treatment during slaughter. This study aimed to assess the onset of unconsciousness in Atlantic halibut immersed in CO2-saturated seawater through electroencephalography (EEG). Of the 29 fish studied, 10 exhibited escape attempts, indicating aversion to CO2-saturated water despite its oxygenation. EEG signals showed four distinct phases: transitional, excitation (high amplitude–high frequency), suppressed, and iso-electric phases. The onset of the suppressed phase, indicative of unconsciousness, occurred on average 258.8 ± 46.2 s after immersion. The spectral analysis of the EEG signals showed a progressive decrease in median frequency, spectral edge frequency, and high frequency contribution, which corresponded to the gradual loss of consciousness. The study concludes that CO2-saturated water is not recommended for pre-slaughter handling of halibut due to the extended time required for the onset of unconsciousness and the observed aversive behaviour. Ensuring humane treatment during slaughter is important for addressing public concern and safeguarding fish welfare in all stages of production. [ABSTRACT FROM AUTHOR]

Published
2023
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26. Gjenfangst, bedøvelse, avliving og etterbruk av rensefisk (CleanCatch). Sluttrapport FHF-prosjekt 901560

Author

Foss, Atle, Bjelland, Reidun Marie, Skiftesvik, Anne Berit, Voldnes, Gøril, Ageeva, Tatiana Nikolaevna, Heide, Morten, Hermansen, Øystein, Hogrenning, Egil, Kvalvik, Ingrid, Nikitina, Ekaterina, Stormo, Svein Kristian, and Roth, Bjørn

Abstract

Denne rapporten tar for seg utfordringer knyttet til temaene gjenfangst, avlivning og etterbruk av rensefisk som har hatt deler av sin livssyklus i merdene sammen med laksefisk for å spise lus. Gjenfangst av rensefisk er både tids- og arbeidskrevende, og i dette prosjektet har vi undersøkt om det er mulig å effektivisere gjenfangst av både rognkjeks og leppefisk ved å dressere fisken ved hjelp av spesifikke lyd- og/eller lyssignal. Det har blitt gjort forsøk på individ- og gruppenivå, i små og store kar, i små og full-skala merder, og alle forsøk i mindre skala viser at både rognkjeks og leppefisk er i stand til å lære, og huske, at slike signaler er relatert til en belønning, med det resultatet at en stor andel av fisken dermed trekkes mot, og samles ved, et spesifikt referansepunkt i karet/merden. Det var ikke mulig å konkludere en effekt i full-skala merder. Prosjektet har også hatt som mål å utvikle en slakteprosedyre som egner seg for industriell slakt av leppefisk og rognkjeks og som tilfredsstiller kravet om dyrevelferd og samtidig ivaretar kvalitet på produktet som mulig matvare. Resultater viser at både rognkjeks, berggylt og bergnebb kan bedøves innen 0.5 sekund i både i vann og luft. Dette gjør det mulig å anvende ulike teknologier, enten om det er tørrbedøving eller i pumpesystemer, for bedøving i kommersielle anlegg. Prosjektet har videre forsket på muligheter og utfordringer knyttet til etterbruk av rensefisk hvor vi har identifisert næringsmessige og prosesstekniske produktegenskaper som er viktig for å kunne bruke rensefisken til humant konsum. Både berggylte og rognkjeks har god proteinkvalitet og fettsyresammensetning og kan være en god kilde til B12- og D13-vitaminer, men markedsundersøkelser i Sør-Korea viser at salg av hel rensefisk til humant konsum kan være utfordrende på grunn av utseende, smak, konsistens og lusespiserhistorien til fiskene.

Published
2021

28. Interaction between temperature and photoperiod on growth and feeding of Atlantic cod (Gadus morhua): possible secondary effects

Author

Imsland, Albert Kjartansson, Foss, Atle, Alvseike, Thomas, Folkvord, Arild, Stefansson, Sigurd Olav, and Jonassen, Thor Magne

Subjects
Body size -- Environmental aspects, Codfish -- Environmental aspects, Codfish -- Food and nutrition, Codfish -- Growth, Photoperiodism -- Research, Company growth, Earth sciences
Abstract

Abstract: Interactions between temperature and photoperiod on growth of Atlantic cod (Gadus morhua) juveniles (initial weight 9.1 g) were studied by rearing juvenile cod 3 months under simulated natural photoperiod [...]

Published
2007

34. Myosin expression levels and enzyme activity in juvenile spotted wolffish (Anarhichas minor) muscle: a method for monitoring growth rates

Author

Imsland, Albert K., Le Francois, Nathalie R., Lamarre, Simon G., Ditlecadet, Delphine, Sigurosson, Sindri, and Foss, Atle

Subjects
Myosin -- Research, Fishes -- Physiological aspects, Earth sciences
Abstract

Abstract: The activity of glycolytic enzymes and the expression levels of myosin RNA was monitored in the white muscle of juvenile spotted wolffish (Anarhichas minor) reared under different temperature regimes. [...]

Published
2006

47. Effects of altered photoperiod regimes during winter on growth and gonadosomatic index in Arctic charr (Salvelinus alpinus) reared in freshwater.

Author

Foss, Atle, Siikavuopio, Sten I., and Imsland, Albert K. D.

Subjects
*ARCTIC char, *FISH farming, *CONTINUOUS groups, *WINTER, *GEOGRAPHICAL distribution of fishes, *FISH growth
Abstract

The short‐ and long‐term effects of altered photoperiods during winter on growth and final gonadosomatic index (GSI) were investigated in 178 individually tagged 2‐year‐old smolt Arctic charr from an anadromous strain. The fish were reared at ambient temperature (2.3–12.5°C) for 18 months and reared at five different photoperiods. One group was reared on constant LD16:8 (light–dark, N = 40) photoperiod and a second group on continuous light (LD24:0, N = 32) throughout the experimental period. Three groups of fish were moved from LD16:8 to LD24:0 for 44 days and subsequently back to LD16:8, that is early winter light group (Early WL: 17 November–5 January; N = 35), Mid WL group (5 January–23 February; N = 38) and Late WL group (23 February–6 April; N = 33). No differences in growth were found for females, whereas males reared at constant LD24:0 were larger (mean ± SEM, 1,780 g ± 180) compared with the Late (1,264 g ± 101) and Mid WL (1,413 g ± 120) groups towards the end the study. Exposure to continuous light during early winter significantly influenced the GSI in female Arctic charr, whereas no differences were found in the males. Female GSI (%) was lowest in the Mid WL group (1.7) and highest in the LD24:0 group (7.0). In conclusion, the present study demonstrated that application of brief continuous light treatments during January and February can possibly be used as a tool to lower subsequent female maturation in Arctic charr farming. [ABSTRACT FROM AUTHOR]

Published
2020
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