Article
Multidisciplinary Sciences
Elan J. Portner, Owyn Snodgrass, Heidi Dewar
Summary: This study examines the foraging ecology of Pacific bluefin tuna in the California Current System. They found that the tuna's diet and foraging behavior varied over time, depending on the availability of prey. The study also highlights the importance of understanding the foraging ecology of this species for predicting its responses to changes in resource availability and its impact on fisheries.
Article
Physiology
Takashi Kitagawa, Takaaki K. Abe, Keitaro Kubo, Ko Fujioka, Hiromu Fukuda, Yosuke Tanaka
Summary: This study aimed to clarify the development of the ability of Pacific bluefin tuna (PBT) to maintain a high body temperature. The research found that PBT can maintain higher body temperatures as they grow and their ability to maintain a high body temperature is independent of the surrounding ambient temperature when the fish reach a certain size. The study also revealed the changes in whole-body heat-transfer coefficient and heat-production rate during growth.
FRONTIERS IN PHYSIOLOGY
(2022)
Article
Agriculture, Dairy & Animal Science
Tomoki Honryo, Yoshifumi Sawada, Yasunori Ishibashi
Summary: This study validates the impact of nighttime lighting on the growth and survival of Pacific bluefin tuna juveniles, showing that it effectively prevents collision deaths and promotes feeding. The aggregation of various live prey under nighttime lighting enhances the viability and growth of the juvenile fish, providing a valuable technique for their cultivation.
Article
Multidisciplinary Sciences
John A. Mohan, Heidi Dewar, Owyn E. Snodgrass, Nathan R. Miller, Yosuke Tanaka, Seiji Ohshimo, Jay R. Rooker, Malcom Francis, R. J. David Wells
Summary: Understanding the movement behaviors and population connectivity of highly migratory fishes like bluefin tuna is crucial for their conservation and management. This study analyzed otolith biominerals of large Pacific bluefin tuna to investigate patterns of trace element distribution across ontogeny. The results showed enrichment and subsequent decrease in element:Ca ratios, indicating potential influences of thermal and metabolic physiologies, common diets, or ambient water chemistry during early life. Variability in other otolith elements differed by capture region, suggesting the influence of ocean-specific environmental factors or growth-related physiologies on otolith mineralization.
Review
Oceanography
Taketoshi Kodama, Atsushi Tawa, Taiki Ishihara, Yosuke Tanaka
Summary: Bullet tuna and Pacific bluefin tuna larvae coexist in the Sea of Japan, but the former has unique ecological characteristics that allow for their coexistence despite competition with the latter.
PROGRESS IN OCEANOGRAPHY
(2022)
Article
Fisheries
Takuya Sato, Ken-ichi Nakamura, Atsushi Nishimoto, Atsushi Tawa, Taketoshi Kodama, Nobuaki Suzuki, Hiroshi Ashida, Hiroshige Tanaka
Summary: The study identified fish, cephalopods, and copepods as the main prey items for juvenile Pacific bluefin tuna in the Sea of Japan. Larger juveniles showed a preference for both fish and cephalopods while smaller juveniles mainly consumed fish. The nitrogen isotope ratios and feeding habits suggested an increase in trophic level and active feeding on fish as the juveniles grew in size.
MARINE AND FRESHWATER RESEARCH
(2022)
Article
Limnology
Xiaoshuai He, Yi-Sheng Chen, Shin-Jing Ang, Jen-Chieh Shiao, Chun-Mao Tseng, John R. Reinfelder
Summary: The sources of methylmercury (MeHg) in Pacific bluefin tuna (PBT) from the western North Pacific Ocean (WPO) were investigated using mercury stable isotopes. The study found that the source of MeHg accumulated by PBT changes as they age, with larger PBT accumulating more MeHg from epipelagic prey in the Kuroshio extension. In addition, the sources of MeHg in the WPO food web appear to be different from those in the central and eastern North Pacific.
LIMNOLOGY AND OCEANOGRAPHY LETTERS
(2023)
Article
Oceanography
Jen-Chieh Shiao, Jhen Hsu, Ching-Chun Cheng, Wen-Yu Tsai, Han-Bo Lu, Yosuke Tanaka, Pei-Lin Wang
Summary: The Pacific bluefin tuna is an economically important species, but its population has decreased due to overexploitation. Research shows that most tuna spawn in the Western North Pacific, with 69% showing trans-Pacific migration, supporting the one-stock hypothesis.
DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS
(2021)
Article
Multidisciplinary Sciences
Yulina Hane, Takayuki Ushikubo, Yusuke Yokoyama, Yosuke Miyairi, Shingo Kimura
Summary: Accurate understanding of changing population dynamics associated with climate change is crucial for managing highly migratory fish species. In this study, stable oxygen isotope analysis was conducted on the otoliths of Pacific bluefin tuna using SIMS, revealing variations in thermal environments during larvae stage and a correlation between temperature difference and spawning season.
Article
Biology
Abigail M. Downs, Allison Kolpas, Barbara A. Block, Frank E. Fish
Summary: Tuna's rigid body should limit their turning performance, but they overcome this limitation by increasing the flexibility of their tail and utilizing specific turning behaviors.
JOURNAL OF EXPERIMENTAL BIOLOGY
(2023)
Article
Multidisciplinary Sciences
Akito Taniguchi, Ryuichiro Aoki, Isamu Inoue, Mitsuru Eguchi
Summary: In this study, we investigated the succession process of intestinal bacteria during seed production of Pacific bluefin tuna. The results showed a clear succession of intestinal bacteria during the seed production process. Proper management of the seed production process is crucial for the aquaculture of healthy fish.
Article
Environmental Sciences
Anais Medieu, David Point, Aurore Receveur, Olivier Gauthier, Valerie Allain, Heidi Pethybridge, Christophe E. Menkes, David P. Gillikin, Andrew T. Revill, Christopher J. Somes, Jeremy Collin, Anne Lorrain
Summary: Through studying the mercury concentrations in three tropical tuna species in the southwestern Pacific Ocean, it was found that there were significant inter-annual variability in mercury concentrations in tuna, but no clear long-term trend was observed. The influence of amino acids and model-estimated phytoplankton δN-15 values on mercury concentrations in tuna was highlighted.
Article
Multidisciplinary Sciences
Takao Hayashida, Satoshi Soma, Yoji Nakamura, Kentaro Higuchi, Yukinori Kazeto, Koichiro Gen
Summary: This study elucidates the molecular mechanisms of gonadal sex differentiation in tunas. In the female gonads, the expression of foxl2 and cyp19a1a induces ovarian differentiation, while in the male gonads, the upregulation of dmrt1 and gsdf promotes testicular differentiation. Androgen biosynthesis also plays a crucial role in male gonad differentiation.
SCIENTIFIC REPORTS
(2023)
Article
Multidisciplinary Sciences
Naoto Ienaga, Kentaro Higuchi, Toshinori Takashi, Koichiro Gen, Koji Tsuda, Kei Terayama
Summary: The study explores the use of deep neural networks to predict egg quality based solely on photographic images, achieving higher accuracy than human experts in predicting hatching success and larvae survival. The results suggest the applicability of deep learning techniques to efficient egg quality prediction and analysis of early developmental stages.
SCIENTIFIC REPORTS
(2021)
Article
Ecology
Jose Luis Varela, Antonio Medina, Santiago Deniz, Francisco Javier Abascal
Summary: This study investigated the trophic biology of Atlantic bluefin tuna (ABFT) in the Canary Islands, showing that ABFT actively foraged on fish prey, primarily snipefish. Plastic debris was also found in some stomachs. Isotopic analysis indicated inter-annual differences in diet, with a more diverse diet in 2017. The results suggest that the Canary Islands serve as a foraging ground for ABFT.
MARINE ECOLOGY PROGRESS SERIES
(2022)
Article
Fisheries
Tatsuru Kadota, Toshinori Takashi, Masakazu Oka, Kentaro Higuchi, Koichiro Gen, Yosuke Tanaka, Sayumi Sawaguchi, Keiichi Mushiake
Article
Fisheries
Kentaro Higuchi, Koichiro Gen, Daisuke Izumida, Yukinori Kazeto, Takuro Hotta, Toshinori Takashi, Hideaki Aono, Kiyoshi Soyano
Article
Fisheries
Yosuke Tanaka, Kazunori Kumon, Kentaro Higuchi, Takeshi Eba, Akefumi Nishi, Hideki Nikaido, Satoshi Shiozawa
JOURNAL OF THE WORLD AQUACULTURE SOCIETY
(2018)
Article
Fisheries
Kentaro Higuchi, Kazunori Yoshida, Koichiro Gen, Hiroyuki Matsunari, Toshinori Takashi, Keiichi Mushiake, Kiyoshi Soyano
Article
Endocrinology & Metabolism
Mitsuo Nyuji, Kazuhisa Hamada, Yukinori Kazeto, Miyuki Mekuchi, Koichiro Gen, Kiyoshi Soyano, Koichi Okuzawa
GENERAL AND COMPARATIVE ENDOCRINOLOGY
(2018)
Article
Endocrinology & Metabolism
Haruna Amano, Akihiro Kotake, Naoshi Hiramatsu, Toshiaki Fujita, Takashi Todo, Jun-ya Aoki, Kiyoshi Soyano, Hirohiko Kagawa, Akihiko Hara
GENERAL AND COMPARATIVE ENDOCRINOLOGY
(2019)
Article
Reproductive Biology
Kentaro Higuchi, Rie Goto, Junpei Konishi, Yoshiaki Ina, Yukinori Kazeto, Koichiro Gen
Article
Multidisciplinary Sciences
Kentaro Higuchi, Yukinori Kazeto, Yuichi Ozaki, Toshiya Yamaguchi, Yukinori Shimada, Yoshiaki Ina, Satoshi Soma, Yoshitaka Sakakura, Rie Goto, Takahiro Matsubara, Issei Nishiki, Yuki Iwasaki, Motoshige Yasuike, Yoji Nakamura, Aiko Matsuura, Shukei Masuma, Tetsushi Sakuma, Takashi Yamamoto, Tetsuji Masaoka, Takanori Kobayashi, Atushi Fujiwara, Koichiro Gen
SCIENTIFIC REPORTS
(2019)
Article
Fisheries
Aung Naing Win, Wataru Yamazaki, Takamasa Hasegawa, Kentaro Higuchi, Toshinori Takashi, Koichiro Gen, Tetsuya Sumida, Atsushi Hagiwara, Yoshitaka Sakakura
Article
Fisheries
Takao Hayashida, Kentaro Higuchi, Kazuharu Nomura, Junpei Konishi, Yukinori Shimada, Kogen Okita, Toshinori Takashi, Yukinori Kazeto, Koichiro Gen
Summary: This study investigated the optimal cold-shock conditions for inducing triploidy in Pacific bluefin tuna, finding that starting the treatment 5 minutes after fertilization at 5 degrees C for 15 minutes resulted in high triploidization rates. This method could potentially help address the issue of muscle fat content reduction during sexual maturation in aquaculture-produced Thunnus orientalis.
Article
Multidisciplinary Sciences
Naoto Ienaga, Kentaro Higuchi, Toshinori Takashi, Koichiro Gen, Koji Tsuda, Kei Terayama
Summary: The study explores the use of deep neural networks to predict egg quality based solely on photographic images, achieving higher accuracy than human experts in predicting hatching success and larvae survival. The results suggest the applicability of deep learning techniques to efficient egg quality prediction and analysis of early developmental stages.
SCIENTIFIC REPORTS
(2021)
Article
Biochemistry & Molecular Biology
Yoji Nakamura, Kentaro Higuchi, Kazunori Kumon, Motoshige Yasuike, Toshinori Takashi, Koichiro Gen, Atushi Fujiwara
Summary: This study identified a unique region in the male genome of Pacific bluefin tuna carrying a male-specific haplotype, which was predicted to encode the gene sult1st6y. Analysis of RNA-seq data of southern bluefin tuna revealed that sult1st6y was expressed only in male testes, potentially inhibiting female development. These findings suggest a promising hypothesis that sult1st6y may play a crucial role in sex determination in Thunnus fishes.
INTERNATIONAL JOURNAL OF GENOMICS
(2021)
Article
Fisheries
Takao Hayashida, Kentaro Higuchi, Kogen Okita, Yukinori Kazeto, Masaomi Hamasaki, Sota Yoshikawa, Toshinori Takashi, Koichiro Gen
Summary: This study aimed to investigate sexual dimorphism in aquaculture-produced Pacific bluefin tuna (PBT) and develop techniques for sex manipulation. It was found that male-cultured PBTs were larger than females in body size. The results provide the basis for future studies on mono-sex male production technology in PBT.
AQUACULTURE RESEARCH
(2023)
Article
Multidisciplinary Sciences
Kentaro Higuchi, Yukinori Kazeto, Yuichi Ozaki, Daisuke Izumida, Takuro Hotta, Kiyoshi Soyano, Koichiro Gen
Article
Fisheries
Kentaro Higuchi, Kazunori Yoshida, Koichiro Gen, Mitsuo Nyuji, Toshinori Takashi, Keiichi Mushiake, Kiyoshi Soyano