Population dynamics of the euphausiids Euphausia pacifica and Thysanoessa inspinata in the Oyashio region during the 2007 spring phytoplankton bloom SCIE SCOPUS

Cited 6 time in WEB OF SCIENCE Cited 5 time in Scopus
Title
Population dynamics of the euphausiids Euphausia pacifica and Thysanoessa inspinata in the Oyashio region during the 2007 spring phytoplankton bloom
Author(s)
Kim, Hye Seon; Yamaguchi, Atsushi; Ikeda, Tsutomu
Publication Year
2010-09
Abstract
The abundance and population structure of Euphausia pacifica and Thysanoessa inspinata were investigated during the period 9 March-29 April 2007 at a single station in the Oyashio region. Water temperature and chlorophyll a concentration varied from 1.1 to 6.1 degrees C and from 0.02 to 6.3 mg m(-3), respectively, primarily reflecting the effects of varying mixtures of the water masses prevailing in this region. The abundance of euphausiids, collected by oblique hauls with Bongo nets (0-200 m) at night, fluctuated from 41 to 1040 individuals m(-2) for E. pacifica and from 50 to 186 individuals m(-2) for T. inspinata. Correlation analyses revealed that the variations in the abundance of E. pacifica were related to water temperature and chlorophyll a, while abundance of T. inspinata only varied with temperature. Adult males and females (with and without spermatophores) were the major components of both euphausiid stocks (> 90% of the total). Modal size (= total length or TL) analysis revealed that one group with large sizes (14-18 mm TL for E. pacifica, 16-18 mm TL for T. inspinata) occurred throughout the study period, often accompanied by one discrete group of smaller individuals (< 11 mm TL for both euphausiids), suggesting the distribution of the same euphausiid populations across the heterogeneous water masses. Adult males were significantly smaller than adult females in T. inspinata, but this was not the case in E. pacifica. Tracing the progressive increase in the mean sizes of the larger size groups, growth rates were estimated to be 0.082 mm day(-1) for E. pacifica and 0.022 mm day(-1) for T. inspinata. The difference in the growth rates of the two euphausiids is discussed in light of species-specific differences in the allocation of energy to reproduction and somatic growth during the present study period. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.
ISSN
0967-0645
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/4041
DOI
10.1016/j.dsr2.2010.03.016
Bibliographic Citation
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY, v.57, no.17-18, pp.1727 - 1732, 2010
Publisher
PERGAMON-ELSEVIER SCIENCE LTD
Subject
NORTH-EASTERN JAPAN; SUB-ARCTIC PACIFIC; VERTICAL-DISTRIBUTION; COASTAL WATERS; GROWTH; MIGRATION; BIOMASS; SEA; CALIFORNIA; CRUSTACEA
Keywords
Euphausia pacifica; Thysanoessa inspinata; Oyashio region; Euphausiids; Population structure; Phytoplankton bloom
Type
Article
Language
English
Document Type
Article
Publisher
PERGAMON-ELSEVIER SCIENCE LTD
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