Internal wave-mediated shading causes frequent vertical migrations in fishes

Handle URI:
http://hdl.handle.net/10754/555758
Title:
Internal wave-mediated shading causes frequent vertical migrations in fishes
Authors:
Kaartvedt, Stein ( 0000-0002-8793-2948 ) ; Klevjer, TA; Aksnes, Dag L. ( 0000-0001-9504-226X )
Abstract:
We provide evidence that internal waves cause frequent vertical migrations (FVM) in fishes. Acoustic data from the Benguela Current revealed that pelagic scattering layers of fish below ~140 m moved in opposite phases to internal waves, ascending ~20 m towards the wave trough and descending from the wave crest. At the trough, the downward displacement of upper waters and the upward migration of fish created an overlapping zone. Near-bottom fish correspondingly left the benthic boundary zone at the wave trough, ascending into an acoustic scattering layer likely consisting of zooplankton and then descending to the benthic boundary zone at the wave crest. We suggest that this vertical fish migration is a response to fluctuations in light intensity of 3 to 4 orders of magnitude caused by shading from a turbid surface layer that had chlorophyll a values of 3 to 4 mg m−3 and varied in thickness from ~15 to 50 m at a temporal scale corresponding to the internal wave period (30 min). This migration frequency thus is much higher than that of the common and widespread light-associated diel vertical migration. Vertical movements affect prey encounters, growth, and survival. We hypothesize that FVM increase the likelihood of prey encounters and the time for safe visual foraging among planktivorous fish, thereby contributing to efficient trophic transfer in major upwelling areas.
KAUST Department:
Red Sea Research Center (RSRC)
Citation:
Internal wave-mediated shading causes frequent vertical migrations in fishes 2012, 452:1 Marine Ecology Progress Series
Journal:
Marine Ecology Progress Series
Issue Date:
25-Apr-2012
DOI:
10.3354/meps09688
Type:
Article
ISSN:
0171-8630; 1616-1599
Additional Links:
http://www.int-res.com/abstracts/meps/v452/p1-10/
Appears in Collections:
Articles; Red Sea Research Center (RSRC); Red Sea Research Center (RSRC)

Full metadata record

DC FieldValue Language
dc.contributor.authorKaartvedt, Steinen
dc.contributor.authorKlevjer, TAen
dc.contributor.authorAksnes, Dag L.en
dc.date.accessioned2015-05-26T07:23:10Zen
dc.date.available2015-05-26T07:23:10Zen
dc.date.issued2012-04-25en
dc.identifier.citationInternal wave-mediated shading causes frequent vertical migrations in fishes 2012, 452:1 Marine Ecology Progress Seriesen
dc.identifier.issn0171-8630en
dc.identifier.issn1616-1599en
dc.identifier.doi10.3354/meps09688en
dc.identifier.urihttp://hdl.handle.net/10754/555758en
dc.description.abstractWe provide evidence that internal waves cause frequent vertical migrations (FVM) in fishes. Acoustic data from the Benguela Current revealed that pelagic scattering layers of fish below ~140 m moved in opposite phases to internal waves, ascending ~20 m towards the wave trough and descending from the wave crest. At the trough, the downward displacement of upper waters and the upward migration of fish created an overlapping zone. Near-bottom fish correspondingly left the benthic boundary zone at the wave trough, ascending into an acoustic scattering layer likely consisting of zooplankton and then descending to the benthic boundary zone at the wave crest. We suggest that this vertical fish migration is a response to fluctuations in light intensity of 3 to 4 orders of magnitude caused by shading from a turbid surface layer that had chlorophyll a values of 3 to 4 mg m−3 and varied in thickness from ~15 to 50 m at a temporal scale corresponding to the internal wave period (30 min). This migration frequency thus is much higher than that of the common and widespread light-associated diel vertical migration. Vertical movements affect prey encounters, growth, and survival. We hypothesize that FVM increase the likelihood of prey encounters and the time for safe visual foraging among planktivorous fish, thereby contributing to efficient trophic transfer in major upwelling areas.en
dc.relation.urlhttp://www.int-res.com/abstracts/meps/v452/p1-10/en
dc.rightsArchived with thanks to Marine Ecology Progress Series © 2012 Inter-Researchen
dc.subjectInternal wavesen
dc.subjectShadingen
dc.subjectAntipredation windowen
dc.subjectVertical migrationen
dc.subjectAcousticsen
dc.titleInternal wave-mediated shading causes frequent vertical migrations in fishesen
dc.typeArticleen
dc.contributor.departmentRed Sea Research Center (RSRC)en
dc.identifier.journalMarine Ecology Progress Seriesen
dc.eprint.versionPublisher's Version/PDFen
dc.contributor.institutionDepartment of Biology, University of Oslo, 0316 Oslo, Norwayen
dc.contributor.institutionDepartment of Biology, University of Bergen, 5020 Bergen, Norwayen
kaust.authorKaartvedt, Steinen
kaust.authorKlevjer, Thor Aleksanderen
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