Growth and welfare of submerged Atlantic salmon under continuous lighting

M Sievers,F Oppedal,T Kristiansen,Pg Fjelldal,O Folkedal,Ø Korsøen,T Dempster

doi:10.3354/aei00289

Abstract

AEI Aquaculture Environment Interactions Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AEI 10:501-510 (2018) - DOI: https://doi.org/10.3354/aei00289 Growth and welfare of submerged Atlantic salmon under continuous lighting M. Sievers1,2,3,*, Ø. Korsøen1, T. Dempster1,2, P. G. Fjelldal1, T. Kristiansen1, O. Folkedal1, F. Oppedal1 1Institute of Marine Research, 5984 Matredal, Norway 2School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia 3Australian Rivers Institute - Coast & Estuaries, School of Environment and Science, Griffith University, Gold Coast, Queensland 4222, Australia *Corresponding author: m.sievers@griffith.edu.au ABSTRACT: Although surface-based cages dominate the marine finfish aquaculture industry, production issues that arise at the surface such as poor environmental conditions and the presence of parasites has spurred interest in submerging cages. However, submerged culture is not without its own issues; for example, the adverse effects on fish buoyancy levels can alter swimming speeds and cause tilted swimming at night time, leading to reduced growth rates and vertebral deformities. The use of continuous artificial lighting is common practice in surface-based salmon farming to inhibit maturation. Its implementation can also increase swimming speeds at night, and, if used in submerged cages, may reduce the incidence of tilted swimming. Here we compared submerged (below 10 m) and surface culture of Atlantic salmon Salmo salar for 42 d under continuous lighting. The use of continuous lightning during submergence of large (3.4 kg) Atlantic salmon increased swimming speeds, reduced tilted swimming, and spinal deformities did not arise. Submerged culture also decreased infestation by attached sea lice stages by 72%, from 4.4 to 1.2 lice per fish. However, specific growth rates of submerged fish were 30% lower than those of surface-reared fish. Developments in engineering and technologies that allow salmon to refill their swim bladders during submergence show promise in eliminating welfare and growth problems. Robust scientific experiments at full commercial scale of cages and operating systems that consider both production and welfare outcomes are critical to the successful development of submerged farming. KEY WORDS: Aquaculture · Lepeophtheirus salmonis · Parasite control · Salmo salar · Sea lice · Mariculture Full text in pdf format PreviousCite this article as: Sievers M, Korsøen Ø, Dempster T, Fjelldal PG, Kristiansen T, Folkedal O, Oppedal F (2018) Growth and welfare of submerged Atlantic salmon under continuous lighting. Aquacult Environ Interact 10:501-510. https://doi.org/10.3354/aei00289 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AEI Vol. 10. Online publication date: November 22, 2018 Print ISSN: 1869-215X; Online ISSN: 1869-7534 Copyright © 2018 Inter-Research.

Highlights

Finfish aquaculture is expanding globally, with global protein production from aquaculture surpassing cattle farming (Ottinger et al 2016)
We demonstrate that the use of standard, continuous artificial lighting during deep, long-term submergence of large Atlantic salmon during winter resulted in night-time swimming speeds that reduced tilted swimming and the associated spinal deformities reported by Korsøen et al (2009)
Submergence of salmon to shallow depths for 2−3 wk has been demonstrated as a possible farming method under certain environmental conditions without major loss of growth or compromising the welfare of fish (Dempster et al 2008, 2009)

Summary

Introduction

Finfish aquaculture is expanding globally, with global protein production from aquaculture surpassing cattle farming (Ottinger et al 2016). The most cultured fish in the sea, Atlantic salmon Salmo salar, is worth over US$ 14 billion yr−1 (FAO 2016). The salmon industry suffers from a range of welfare, social and environmental issues, many of which are a direct result of the surface-based nature of current culture methods. Aquacult Environ Interact 10: 501–510, 2018 threadfin Polydactylus sexfilis (Ryan 2004), cobia Rachycentron canadum (Rapp et al 2007) and Atlantic cod Gadus morhua and haddock Melanogrammus aeglefinus (Chambers & Howell 2006). The adoption of submerged cages unlocks new areas for production where surface-based sea-cage technologies are inappropriate due to surface wind and waves, or by other constraints such as space conflicts with other coastal users (Sanchez-Jerez et al 2016)

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