In the present study, we analysed stomach contents of 585 bigeye tuna (BET; Thunnus obesus) caught in Kuroshio–Oyashio transition zone, a high-productivity region western North Pacific Ocean, to describe feeding habits and prey size. We identified 46 species belonging 40 genera. Fish otoliths squid beaks found stomachs were used calculate body length weight from allometric relationships. The percentage index relative importance (%IRI) was calculated mean occurrence, number each species....

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsTheme Sections 607:207-220 (2018) - DOI: https://doi.org/10.3354/meps12807 Comparative analysis of early growth history Pacific bluefin tuna Thunnus orientalis from different spawning grounds Mikio Watai1, Yuko Hiraoka2, Taiki Ishihara2, Izumi Yamasaki3, Tomoko Ota2, Seiji Ohshimo4, Carlos Augusto Strüssmann5,* 1National...

Lipid and fatty acid composition of female Pacific bluefin tuna (PBF, Thunnus orientalis) reproductive somatic tissues in southwestern North Sea Japan spawning grounds are compared. Total lipid (TL) levels higher liver than white muscle tissues. An increased gonadosomatic index (GSI) during the early season coincided with decreased TL. Levels triacylglycerols (TAG) PBF from Nansei Islands Japan, fishes season, while TAG ovary did not. Concurrent reductions TL increases GSI suggest depletion...

In this study, a hydrogen ionic plasma with relatively low residual fractional electron concentration (ne/n+ ∼ 10−2) is generated using an aluminum grid for the production of negative ions and control ion extraction removal. The composed positive ions, containing molecular ions. Negative are in part produced several volts. A beam 50 eV or more contributes to increase density plasma. energy bias voltage tuned such way that high-density maintained.

Abstract A method for the direct preparation of fatty‐acid methyl esters (FAME) was simplified analysis a single fish larva using gas chromatography (GC). The included isolation larval trunk and drying in glass vial, followed by saponification all contents without prior lipid extraction. Thereafter, fatty acids released were methylated trimethylsilyldiazomethane. This has advantages over another method, acid‐catalyzed transesterification, because both methylation at room temperature can...

Information on the movements of highly migratory species is important to understand their ecology, including habitat use, population connectivity, and stock structure, implement appropriate management conservation measures. The blue shark Prionace glauca (Carcharhinidae) migratory, has a global distribution, ecologically economically as one most abundant apex marine predators; however, migration patterns pregnant females are unknown. Here, we used pop-up satellite archival tags elucidate...

Abstract Trace element analysis of otoliths from core to edge was used reveal differences in habitats larvae and early juveniles Japanese jack mackerel ( Trachurus japonicus ) caught the East China Sea (ECS), Pacific Ocean, Japan. Multi‐element signatures (Sr:Ca, Mg:Ca, Na:Ca, K:Ca, Ba:Ca) were analyzed with multivariate statistics determine whether these provide insight into regional population structure. The median values elements: Ca ratios otolith region differed significantly among...

Abstract Recruitment of age‐0 Pacific bluefin tuna ( Thunnus orientalis ) from 1952 to 2014 was examined by a sequential regime shift detection method. The shifts in recruitment were detected 1957, 1972, 1980, 1994 and 2009. durations ranged 8–15 years averaged 13.0 years. In both the total (1952–2014) data rich (1980–2014) periods, negative relationships found between Decadal Oscillation autumn, positive sea surface temperature (SST) anomalies northern part East China Sea, southwestern Sea...

Spatial segregation is a key component to understand the ecology of highly migratory species; however, this aspect poorly known for many pelagic shark species. We investigated spatial by sex and life-history stage in blue sharks Prionace glauca northwestern Pacific, using satellite tracking data gathered from 74 electronic tags as well fisheries-dependent size-measurement datasets, which allowed us update schematic diagram migration patterns population. Blue were tracked 30 271 d (mean 125...

Abstract We investigated the effect of feeding habits on fatness (length–weight relationship ( LW )) and otolith growth age‐0 Pacific bluefin tuna PBF ) (fork length FL 15.0–29.9 cm) collected off southwestern coast Japan from July to August during 2010–2015. The rate Clupeiformes FR c) was substantially influenced by path Kuroshio Current early summer. suggest that following patterns occurred in . In 2012 2014, short distance provided high overlap between increased opportunity for feeding,...

Differences in the reproductive traits of Pacific bluefin tuna Thunnus orientalis (PBF) Sea Japan (SOJ) were investigated to evaluate potential 3 fishing grounds (i.e. northern, central and southern areas). The size distribution PBF differed among grounds, with smaller fish (100-130 cm fork length, FL) being caught northern areas SOJ. Spawning-capable females found at sea surface temperatures (SSTs) between 17 25°C, most SSTs >21°C. Seasonal changes SST period when exceeded 21°C each...

We analyzed stable isotope ratios, fatty acid, and lipid components of chub mackerel, Scomber japonicus , to evaluate their applicability as chemical biomarkers. Chub mackerel were collected in the East China Sea, Sea Japan, Pacific Ocean, with body sizes ranging from 51 388 mm. The total acid contents (mg g –1 ) increased growth, percent composition acids lipids changed drastically. percentages docosahexaenoic (%DHA), stearic (%Ste), arachidonic (%ARA) decreased percentage oleic (%Ole) when...

In this study, hydrogen electron plasma is irradiated on an aluminum plate, and negative ions are produced the plate surface. Hydrogen ionic maintained near surface, where a deflection magnetic field applied using pair of magnets in vicinity When no applied, not formed. The interface position between depends quantity flux density. that controls toward while maintaining quasi-neutrality, indispensable for formation plasma.

This paper proposes a one-step method for preparation of fluorescent 9-anthrylmethyl esters from triacylglycerols (TAG) ranging in amount 0.1 to 5 microg. It involves base-catalyzed transesterification using potassium 9-anthracenemethoxide, prepared by proton exchange between 9-anthracenemethanol and tert-butoxide. Transesterification 10 min at room temperature gave the fatty acid nearly maximal yields (82-85%). The products could be analyzed reversed-phase HPLC without purification....

クロマグロの資源評価には,統合型資源評価モデルが用いられており,漁獲物を代表するサイズ組成は,重要な入力情報のひとつである。本研究では,24道県から収集した定置網漁業の漁獲量とサイズ組成データを層化し,一般化線形モデルによる基準を用いた段階的引きのばし手法により,日本沿岸で漁獲されるクロマグロのサイズ組成を推定した。結果より,定置網で漁獲されるクロマグロのおよそ60%は,秋季から冬季に漁獲される0歳魚であること,1歳魚以上は夏季から冬季の本州太平洋側北部や青森県以北で主に漁獲されることが示された。