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Occurrence and density of P acific saury C ololabis saira larvae and juveniles in relation to environmental factors during the winter spawning season in the K uroshio C urrent system
Author(s) -
Takasuka Akinori,
Kuroda Hiroshi,
Okunishi Takeshi,
Shimizu Yugo,
Hirota Yuichi,
Kubota Hiroshi,
Sakaji Hideo,
Kimura Ryo,
Ito ShinIchi,
Oozeki Yoshioki
Publication year - 2014
Publication title -
fisheries oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 80
eISSN - 1365-2419
pISSN - 1054-6006
DOI - 10.1111/fog.12065
Subject(s) - juvenile , larva , salinity , biology , chlorophyll a , sea surface temperature , fishery , temperature salinity diagrams , oceanography , ecology , zoology , botany , geology
The occurrence and density of P acific saury C ololabis saira larvae and juveniles were examined in relation to environmental factors during the winter spawning season in the K uroshio C urrent system, based on samples from extensive surveys off the Pacific coast of Japan in 2003–2012. Dense distributions of larvae and juveniles were observed in areas around and on the offshore side of the Kuroshio axis except during a large Kuroshio meander year (2005). The relationships of larval and juvenile occurrence and density given the occurrence to sea surface temperature ( SST ), salinity ( SSS ), and chlorophyll‐ a concentration ( CHL ) were examined by generalized additive models for 10‐mm size classes up to 40 mm. In general, the optimal SST for larval and juvenile occurrence and density given the occurrence was consistently observed at 19–20°C. The patterns were more complex for SSS , but a peak in occurrence was observed at 34.75–34.80. In contrast, there were negative relationships of occurrence and density given the occurrence to CHL . These patterns tended to be consistent among different size classes, although the patterns differed for the smallest size class depending on environmental factors. Synthetically, the window for spawning and larval and juvenile occurrence and density seems to be largely determined by physical factors, in particular temperature. The environmental conditions which larvae and juveniles encounter would be maintained while they are transported. The survival success under the physically favorable but food‐poor conditions of the Kuroshio Current system could be key to their recruitment success.