scholarly journals Habitat use of adult Pacific bluefin tuna Thunnus orientalis during the spawning season in the Sea of Japan: evidence for a trade-off between thermal preference and reproductive activity

Author(s):  
K Fujioka ◽  
K Sasagawa ◽  
T Kuwahara ◽  
EE Estess ◽  
Y Takahara ◽  
...  
2016 ◽  
Vol 174 ◽  
pp. 30-39 ◽  
Author(s):  
Yumi Okochi ◽  
Osamu Abe ◽  
Sho Tanaka ◽  
Yukio Ishihara ◽  
Akio Shimizu

Author(s):  
Takuya Sato ◽  
Ken-ichi Nakamura ◽  
Atsushi Nishimoto ◽  
Atsushi Tawa ◽  
Taketoshi Kodama ◽  
...  

2018 ◽  
Vol 31 ◽  
pp. 33 ◽  
Author(s):  
Seiji Ohshimo ◽  
Takuya Sato ◽  
Yumi Okochi ◽  
Sho Tanaka ◽  
Taiki Ishihara ◽  
...  

Reproductive characteristics are one of the key factors for understanding population dynamics in fishes. This study describes the spawning habitat of Pacific bluefin tuna (Thunnus orientalis) in the Kuroshio and the Kuroshio–Oyashio transition area. A total of 551 adult fish (fork length > 120 cm) were collected during 1994–2007 (except in 2001 and 2003) and 2016. Based on a histological analysis of the gonads, we concluded that actively spawning females were mainly present in late May to early July. Relative batch fecundity was significantly lower than that reported in the Sea of Japan but was similar to that observed in the Nansei area. Whereas most spawning adults in the Sea of Japan are 3–6 years old and those in the Nansei area are over 10 years old, the majority of the specimens in this study ranged from 160 to 180 cm in length, which corresponds to 6–8 years of age. Our results indicate that Pacific bluefin tuna spawn in the study area and provide important data for understanding the spatiotemporal differences in spawning strategy with growth in this species.


2018 ◽  
Vol 75 (4) ◽  
pp. 1341-1352 ◽  
Author(s):  
Barbara A Muhling ◽  
Desiree Tommasi ◽  
Seiji Ohshimo ◽  
Michael A Alexander ◽  
Gerard DiNardo

Abstract Future sustainable management of fisheries will require resilience to the effects of environmental variability and climate change on stock productivity. In this study, we examined relationships between sea surface temperature (SST) in the region between Taiwan and the Sea of Japan, and annual recruitment of Pacific bluefin tuna (Thunnus orientalis: PBF) over the past 35 years. Spatial correlation maps showed that warmer SSTs south of Shikoku, in the East China Sea and in the Sea of Japan from summer to late fall were associated with above average recruitment. SST anomalies near larval and juvenile habitats were most strongly correlated with local air temperatures. Generalized Additive Models predicting annual PBF recruitment from SST fields suggested that the influence of SST on recruitment was stronger than that of spawning stock biomass. Correlations between SST and recruitment likely reflect biological processes relevant to early juvenile habitat suitability. The influence of late fall SSTs could also be a result of varying availability of age-0 fish to the troll fishery; however, the relative importance of these processes was not clear. Despite these knowledge gaps, the strong predictive power of SST on PBF recruitment can allow more proactive management of this species under varying environmental conditions.


2020 ◽  
Vol 86 (6) ◽  
pp. 1019-1028
Author(s):  
Hiroshige Tanaka ◽  
Taketoshi Kodama ◽  
Nobuaki Suzuki ◽  
Yosuke Mochizuki ◽  
Hiroshi Ashida ◽  
...  

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