영일만 쇄파대에 나타나는 부유성 요각류의 주야 수평이동 OTHER

Title
영일만 쇄파대에 나타나는 부유성 요각류의 주야 수평이동
Alternative Title
Diel Horizontal Migration of Planktonic Copepods in the Surf Zone of Yongil Bay, Korea
Author(s)
서해립; 유옥환
KIOST Author(s)
Yu, Ok Hwan(유옥환)
Publication Year
1996-07
Abstract
The patterns of diel horizontal migration (DHM) of 7 copepod species are compared as part of a general investigation of the zooplankton adaptations to the surf zone habitats. In a sandy shore surf zone of Yongil Bay, 3 sites such as the bottom and surface of 1 m water depth and water's edge are sampled with a sledge net(n=108). The surf zone copepod assemblage is dominated by 7 species; Acartia hudsonica, Fseudodiaptomus marinus, Paracalanus indicus, Calanus sinicus, Oithona similis, Sinocalanus tenellus and Labidocera bipinnata. Threefold variations in copepod abundance are observed within a diel cycle. Abundances of 7 dominant species and total copepods captured in the surface exhibit significant diel differences, but those taken in the bottom are not significantly affected by diel period. It is shown that about 90% of the surf zone copepods performed DHM. The nocturnal high densities of copepods occurred for a neap tide when the offshore winds prevailed, suggesting the animals' ability for horizontal orientation and an active locomotion without invoking passive transportation by currents. Photoreactive behavior of copepods triggered by relative changes in light intensity may be a primary factor inducing DHM by aggregating in the surf zone during the night and spreading out at day; then copepods may reduce encounters with visual predators. In A. hudsonica, ontogenetic variations in timings of DHM are evident. Such variations are likely to minimize intraspecific competition for diets. Data on shoreward migration of copepods indicate that A. hudsonica, P. indicus, O. similis and S. tenellus can maintain swimming velocities of about 20mh−1 for durations of more than an hour. Our observations of strong diel difference in abundances point out the need for both day and night samplings in surf zone habitats, if the importance of these habitats to planktonic copepods are to be fully understood.
ISSN
0374-8111
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/6450
Bibliographic Citation
한국수산과학회지, v.29, no.4, pp.527 - 536, 1996
Publisher
한국수산과학회
Keywords
surf zone; planktonic copepods; diel horizontal migration; swimming velocity
Type
Article
Language
Korean
Publisher
한국수산과학회
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