The cause of death of juvenile Pacific bluefin tuna (Thunnus orientalis) reared in sea net cages

Okada, Tokihiko; Honryo, Tomoki; Sawada, Yoshifumi; Agawa, Yasuo; Miyashita, Shigeru; Ishibashi, Yasunori

doi:10.1016/j.aquaeng.2014.01.001

Cited by 18 publications

(27 citation statements)

References 7 publications

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“…In this study, the frequency of the ingestion of foreign particles was lower than that previously reported (Okada et al, 2014). It was only 0%-9.6% in the control cage and 2.2%-8.3% in the small-large group.…”

Section: Estimated Frequency and Mortality Rate Of Each Factorcontrasting

confidence: 82%

Improving rearing performance in sea‐cage culture of Pacific bluefin tuna Thunnus orientalis juveniles (Temminck and Schlegel) using small sea cages

et al. 2020

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High levels of mortality occur in large net-cage culture of Pacific bluefin tuna (PBF)Thunnus orientalis due to poor growth on commencement of sea-cage culture obstructing the mass production of fingerlings. Therefore, we carried out this study to develop a countermeasure by using small sea cages (square with 13-m sides). PBF juveniles were directly transferred to a 30-m-diameter cage (control) and compared them to fish transferred to small sea cages for 12 days before being merged into another 30-m-diameter cage. The survival rate, growth performance and potential factors increasing mortality were examined. The results of our study showed that survival rate in small sea cages was approximately 20% higher than that of the control. Poor growth also occurred in the small sea cages; however, its frequency and daily mortality rate were half those in the control. In addition, growth performance such as specific growth rate and weight gain of PBF juveniles in small sea cages significantly increased compared to the control. These results suggest that using small sea cages could be an effective countermeasure for poor growth, which may mitigate the high-mortality conditions of current sea-cage culture systems for PBF. K E Y W O R D Scause of death, fingerling production, net-cage size, Pacific bluefin tuna, survival

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Section: Estimated Frequency and Mortality Rate Of Each Factorcontrasting

confidence: 82%

Improving rearing performance in sea‐cage culture of Pacific bluefin tuna Thunnus orientalis juveniles (Temminck and Schlegel) using small sea cages

et al. 2020

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“…Various attempts at fingerling production of tunas have been examined over the past decade. However, despite the establishment of full‐cycle seedling production of Pacific bluefin tuna Thunnus orientalis (PBF), mass mortality occurring in the early stage of fingerling production still remains as a major obstacle hindering the production efficiency of tuna species (Margulies, Wexler, Bentler, Suter, Masuma, Tezuka, Teruya, Oka, Kanematsu & Nikaido ; Miyashita ; Sawada, Okada, Miyashita, Murata & Kumai ; Margulies, Suter, Hunt, Olson, Scholey, Wexler & Nakazawa ), and studies for improvement of survivability have been conducted in various fields (Kurata, Seoka, Nakagawa, Ishibashi, Kumai & Sawada ; Honryo, Kurata, Okada & Ishibashi ; Ishibashi, Miki, Sawada & Kurata ; Okada, Honryo, Sawada, Agawa, Miyashita & Ishibashi ). Even though yellowfin tuna Thunnus albacares (YFT) supports the largest catch among tuna species, the switching of the supply from fisheries to aquaculture through full‐cycle fingerling production will surely be necessary because YFT are classified into a near threatened species due to the reduction in its resource (IUCN ; FAO ).…”

Section: Introductionmentioning

confidence: 99%

Effect of taurine enrichment in rotifer ( Brachionus sp.) on growth of larvae of Pacific bluefin tuna Thunnus orientalis (Temminck & Schlegel) and yellowfin tuna T. albacares (Temminck & Schlegel)

et al. 2016

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To investigate the dietary effect of taurine on the larval stage of tuna species, Pacific bluefin tuna (PBF) and yellowfin tuna (YFT), larvae were reared until 16 days after hatching (dAH) and 14 dAH, respectively, and replicate samples were fed either non-taurine-enriched rotifers (T-0) or rotifers enriched with 800 mg taurine L À1 (T-800). Most PBF and YFT larvae were at the preflexion stage until 7 and 8 dAH, and there were no differences in the growth performance and total protein content of larvae between the T-0 and T-800 groups (t-test; P > 0.05). Thereafter, however, for larvae of both species, these parameters in the T-800 group significantly increased with enhanced notochord development compared to those in T-0 group (t-test; P < 0.05). Except for the RNA content in PBF larvae, there were no significant differences in changes of DNA and RNA content with larval growth between the T-0 and T-800 groups, but both PBF and YFT larvae showed increased protein DNA À1 and protein RNA À1 ratios in the T-800 group compared to the T-0 group after notochord flexion. This indicates that taurine is an important nutrient for the rapid growth of early stage PBF and YFT larvae, and we conclude that the growth improvement of PBF and YFT larvae by dietary taurine supplementation is due to the increase in protein synthesis efficiency after notochord flexion.

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“…The collected eggs were transferred to the Planta Experimental de Cultivos Marinos, Instituto Español de Oceanografía (IEO), Puerto de Mazarrón (Murcia), Spain for hatching and initial larviculture (Ortega 2015 ; De la Gándara et al 2016 ). Fish were weaned from the live feed stage, fed gilthead sea bream ( Sparus aurata L.) yolk sac larvae as prey, to formulated feed at 27 dah, using a commercial diet (Magokoro®; MGK; Marubeni Nisshin Feed Co., Japan), which had been successfully used as a formulated feed for PBT (Okada et al 2014 ; Kurata et al 2015 ; Honryo et al 2018 ). The ABT were weaned using MGK at 0.6 to 0.9 mm pellet sizes and were completely weaned by 32 dah.…”

Section: Methodsmentioning

confidence: 99%

Performance, feed utilization, and hepatic metabolic response of weaned juvenile Atlantic bluefin tuna (Thunnus thynnus L.): effects of dietary lipid level and source

Betancor

Ortega

Gándara

et al. 2018

Fish Physiol Biochem

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Two trials were performed using extruded diets as on-growing feeds for weaned Atlantic bluefin tuna ( Thunnus thynnus ; ABT) to establish adequate dietary levels of both lipid and omega-3 long-chain polyunsaturated fatty acids (LC-PUFAs), and impacts on lipid metabolism via liver gene expression. In trial A, ABT were fed with either a commercial feed (Magokoro®; MGK) as a reference diet or two experimental feeds differing in lipid levels (15 or 20%) using krill oil (KO) as the single lipid source in order to estimate suitable lipid content. Fish fed MGK displayed the highest growth, followed by 15KO, and therefore a dietary lipid content of 15% was considered preferable to 20% at this stage. In trial B, fish were fed MGK, 15KO, or a feed containing 15% lipid with a blend of KO and rapeseed oil (RO) (1:1, v / v ; 15KORO). Fish fed 15KO and 15KORO showed no difference in weight gain, specific growth rate, and fork length. Increasing dietary lipid level or including vegetable oil, RO, in the feeds did not increase liver lipid content. Liver fatty acid compositions largely reflected dietary profiles confirming very limited endogenous LC-PUFA biosynthesis. Liver of ABT fed 15KO and 20KO displayed the highest contents of docosahexaenoic acid (DHA). The hepatic expression of genes encoding enzymes and transcription factors involved in lipid and fatty acid metabolism, as well as genes encoding antioxidant enzymes, showed that many of these genes were regulated by dietary lipid and LC-PUFA content. Results suggested that ABT juveniles can be on-grown on inert dry feeds that support good fish growth and the accumulation of DHA. Electronic supplementary material The online version of this article (10.1007/s10695-018-0587-9) contains supplementary material, which is available to authorized users.

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The cause of death of juvenile Pacific bluefin tuna (Thunnus orientalis) reared in sea net cages

Cited by 18 publications

References 7 publications

Improving rearing performance in sea‐cage culture of Pacific bluefin tuna Thunnus orientalis juveniles (Temminck and Schlegel) using small sea cages

Improving rearing performance in sea‐cage culture of Pacific bluefin tuna Thunnus orientalis juveniles (Temminck and Schlegel) using small sea cages

Effect of taurine enrichment in rotifer ( Brachionus sp.) on growth of larvae of Pacific bluefin tuna Thunnus orientalis (Temminck & Schlegel) and yellowfin tuna T. albacares (Temminck & Schlegel)

Performance, feed utilization, and hepatic metabolic response of weaned juvenile Atlantic bluefin tuna (Thunnus thynnus L.): effects of dietary lipid level and source

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