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Title
  • en Vertical distribution patterns of pelagic copepods as viewed from the predation pressure hypothesis
Creator
Accessrights open access
Subject
  • Other en Diel vertical migration
  • Other en Ontogenetic vertical migration
  • Other en Oceanic
  • Other en Mesopelagic
  • Other en Bathypelagic
  • NDC 485
Description
  • Abstract en As habitats of pelagic copepods, epipelagic oceanic environments are characterized by greater food availability but higher risks of predation. Both food supply and predation risk rapidly drop with increasing depth. We studied day/night vertical distribution patterns of copepodid stages of 6 epipelagic (Neocalanus cristatus, N. flemingeri, N. plumchrus, Eucalanus bungii, Metridia pacifica, and M. okhotensis), 2 mesopelagic (Gaetanus simplex and Pleuromamma scutullata), and 6 bathypelagic copepods (Gaidius variabilis, Paraeuchaeta elongata, P. birostrata, P. rubra, M. asymmetrica, and M. curticauda) based on zooplankton samples collected from depths of 0~4000 m at stn. Knot (44°N, 155°E) in the western subarctic Pacific. All epipelagic species exhibited ontogenetic vertical migration (OVM) characterized by descent with progression of copepodid stages, although species-specific variations in the degree of its magnitude were seen. One of the 6 epipelagic species (M. pacifica) showed diel vertical migration (DVM) behavior by its ascent to upper layers at night. Mesopelagic species were characterized by a lack of OVM, although their older copepodid stages undertook DVM. Bathypelagic species underwent OVM in a pattern that was the opposite (ascent with progression of development) of that of epipelagic species. No DVM behavior was recognized for bathypelagic species. From the viewpoint of the predation pressure hypothesis, these differential vertical distribution modes of copepods living in dissimilar bathymetric strata can be interpreted as results of life history traits toward reducing predation mortality of early (bathypelagic copepods) or late copepodid stages (epipelagic copepods). The absence of OVM in mesopelagic copepods is a life history trait that falls somewhere between these 2 extremes (the DVM behavior of their late copepodid stages apparently imparts an advantage for better feeding). This explanation appears to be consistent with the observation that the fecundity of these copepods decrease with increasing depth.
Publisher en Biodiversity Research Center, Academia Sinica
Date
    Issued2004-04
Language
  • eng
Resource Type journal article
Version Type VoR
Identifier HDL http://hdl.handle.net/2115/52556
Journal
    • PISSN 1021-5506
    • NCID AA11009396
      • en Zoological studies
      • Volume Number43 Issue Number2 Page Start475 Page End485
File
    • fulltext 475.pdf
    • 310.55 KB (application/pdf)
      • Issued2004-04
Oaidate 2023-07-26