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Vol. 52, 2013
Influence of monsoon-driven hydrographic features on
thaliacean distribution in waters around Taiwan, western North Pacific
Ocean
Zhen-Heng
Liao1, Hung-Yen Hsieh2,3 and Wen-Tseng Lo1*
1Institute
of Marine Biotechnology and Resources, National Sun Yat-sen University,
Kaohsiung 80424, Taiwan
2Institute of Marine Biodiversity and Evolutionary
Biology, National Dong Hwa University, Hualien 97401, Taiwan
3National Museum of Marine Biology and Aquarium,
Pingtung 944, Taiwan
Abstract
Background: The mesoscale
distribution of thaliaceans associated with hydrographic conditions in
the waters around Taiwan was investigated during two different monsoon
seasons in 2004 in order to elucidate possible influences of
hydrological conditions driven by seasonal monsoons on distributional
patterns of thaliaceans.
Results: In total, 18 thaliacean species,
belonging to 12 genera and 3 families, were identified in our samples. Thalia rhomboides, Doliolum denticulatum, Doliolum nationalis, Thalia orientalis, Pyrosoma verticillatum, and Thalia democratica were the six
predominant species and contributed 93% to the total thaliacean
collection by number. Thaliacean assemblages were similar in
composition between seasons, but abundances and species numbers were
higher in summer than in winter. Spatial distribution patterns of
doliolids and salps clearly differed and were closely associated with
hydrographic characteristics. Doliolids were mainly found in
lower-salinity and nutrient-rich shelf and neritic waters; among them, D. denticulatum could be used as an
indicator species of the China Coastal Current. Most salp species
showed higher abundances in warm oceanic waters, such as the Kuroshio
Current, Kuroshio Branch Current, and South China Sea Surface Current.
Conclusions: This study showed that
the succession of water masses driven by monsoons affects seasonal and
particularly spatial distributions of abundances of the thaliacean
assemblage in the area studied.
Key words: Monsoon; Water mass; Taiwan;
Thaliacean; Distribution.
*Correspondence: E-mail: lowen@faculty.nsysu.edu.tw
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