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Fish Welfare Based Classification Method of Ocean Current Speeds at Aquaculture Sites

Abstract

ABSTRACT: A major trend in marine aquaculture is to move production to more exposed sites with occasionally rough ocean current events. However, it is unclear whether fish will thrive in these extreme environments, since thorough descriptions of ambient current conditions with regards to fish welfare is lacking. In the present study, ocean current data were collected using acoustic Doppler current profilers at 5 exposed sites along the Norwegian coast over minimum periods of 5 mo. To evaluate welfare risks, current data was compared to known limits of swimming capabilities, such as onset of behavioural changes and critical swimming speeds (Ucrit), of Atlantic salmon Salmo salar and lumpfish Cyclopterus lumpus. Specifically, at each site, current speeds were classified into 6 categories based on expected impact on swimming behaviours of Atlantic salmon, and duration of currents within each category were inspected using a homogeneous and non-homogeneous criterion for the water column. Current speeds were then compared with projected Ucrit at relevant temperatures and fish sizes of Atlantic salmon and lumpfish. Furthermore, a detailed characterization of extreme events at the most exposed site was performed. Of the 5 locations, only 1 exceeded the Ucrit of Atlantic salmon, while all sites featured currents above Ucrit of lumpfish for up to 33 h at a time. These results suggest that responsible Atlantic salmon farming is possible at sites considered exposed, while lumpfish should be restricted to more sheltered environments. The presented method can be applied for other aquaculture fish species if adequate data are available.
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Category

Academic article

Language

English

Author(s)

Affiliation

  • SINTEF Ocean / Aquaculture
  • SINTEF Ocean / Fisheries and New Biomarine Industry
  • Norwegian University of Science and Technology
  • Institute of Marine Research

Date

06.06.2019

Year

2019

Published in

Aquaculture Environment Interactions

ISSN

1869-215X

Volume

11

Page(s)

249 - 261

View this publication at Norwegian Research Information Repository