Seiji Ohshimo

• ph.D
• Division Head at Fisheries Resources Institute, Fisheries Research Agency and Education

Knowledge of the movements of marine organisms is essential for effective conservation schemes. Here, we investigated the lifetime habitat use of diamond squid, Thysanoteuthis rhombus, collected in the western North Pacific and its marginal seas (the Sea of Japan and the East China sea) during 2021–2022, whose migratory ecology is poorly known, usi...

Pacific bluefin tuna (PBF) Thunnus orientalis have 2 major spawning grounds and migrate widely in the North Pacific Ocean. To understand the population structure and migratory ecology, we analyzed vertebral samples collected from a wide range of ages and areas and then estimated their natal ground from the first annulus in the vertebra, which does...

Japanese jack mackerel ( Trachurus japonicus ) is subject to substantial and escalating commercial harvesting activities, yet its habitat structure is poorly understood. We analyzed the carbon and nitrogen stable isotope ratios (δ ¹³ C and δ ¹⁵ N) of this species to evaluate geographical fluctuations in these ratios, allowing a delineation of the j...

The distribution of Japanese Spanish mackerel Scomberomorus niphonius (JSM) has been expanding in coastal Japan since the 2000s. We investigated the expansion routes into the Pacific Ocean using Anisakis third-stage larvae (L3) as a biological tag. Two hypotheses were considered for the expansion routes: (1) JSM migrating north along the Pacific co...

Trace element analysis of otoliths from core to edge was used to reveal differences in habitats of larvae and early juveniles of Japanese jack mackerel (Trachurus japonicus) caught in the East China Sea (ECS), Pacific Ocean, and Sea of Japan. Multielement signatures (Sr:Ca, Mg:Ca, Na:Ca, K:Ca, and Ba:Ca) were analyzed with multivariate statistics t...

The preferred habitats of the round scad Decapterus maruadsi and five other scads (amberstripe scad D. muroadsi, mackerel scad D. macarellus, red scad D. akaadsi, roughear scad D. tabl, and shortfin scad D. macrosoma) in the East China Sea (ECS) and the Sea of Japan were examined based on catch records of Japanese large- and medium-type purse seine...

Diamond squid Thysanoteuthis rhombus (Troschel, 1857), which can grow to a dorsal mantle length of ~100 cm in 1 year, is an important fisheries resource in subtropical and temperate waters worldwide. Around Japan, it is an important resource in the East China Sea, Sea of Japan, and western North Pacific Subtropical Gyre, including the Kuroshio area...

Understanding biological and environmental factors that influence movement behaviors and population connectivity of highly migratory fishes is essential for cooperative international management and conservation of exploited populations, like bluefin tuna. Pacific bluefin tuna Thunnus orientalis (PBT) spawn in the western Pacific Ocean and then juve...

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, the Sea of Japan, and the Pacific Ocean, with body sizes ranging from 51 to 388 mm. The total fatty acid and lipid contents (mg g ⁻¹ ) i...

Spatial segregation is a key component to understand the ecology of highly migratory species; however, this aspect is poorly known for many pelagic shark species. We investigated spatial segregation by sex and life-history stage in blue sharks Prionace glauca in the northwestern Pacific, using satellite tracking data gathered from 74 electronic tag...

Vertical distribution of zooplankton abundance is essential for understanding the linking primary production to higher-trophic marine organisms. In this study, we investigated the zooplankton abundance at the near-surface layer (0–20 m depth; ZA20) and those at 0–200 m depth (ZA200) from 240 stations in the Sea of Japan (SOJ) and the East China Sea...

Harvest control rules (HCRs) are intended to provide total allowable fishing mortality or catches in response to the current stock status. This study presents candidates for HCRs that can be applied to two Japanese sardine stocks in Japan. Our simulation study suggests that some alternative HCRs outperform currently adopted HCRs in terms of robustn...

We evaluated the growth, reproduction, and feeding habits of striped bonito (Sarda orientalis) in the East China Sea. We collected a total of 289 specimens and determined their age from polished otoliths. The estimated growth function was FLt=586.98{1−exp[−0.76exp(t+0.33)]}, where FLt represents fork length (mm) at age t. Males reached spermiation...

Fatty acid composition and total fatty acids of field-caught Pacific bluefin tuna (PBF) Thunnus orientalis larvae were investigated to identify relationships between spawning ground, physiological condition, and growth rate. Multivariate statistical analyses revealed that both growth rate and environmental conditions at spawning grounds were substa...

Many studies have used stable isotope ratios in marine organisms to infer ecology, but few studies have considered potential temporal changes of baseline isotopic values. Such changes can reflect natural and anthropogenic changes in regional nutrient cycling and food-web ecology. This study evaluated changes in carbon and nitrogen stable isotope ra...

To evaluate the habitat and abundance of Japanese Spanish mackerel, we analyzed catch per unit effort (CPUE) of large and mid-sized Japanese purse-seine vessels in the Yellow Sea, East China Sea and Sea of Japan using a generalized additive model and generalized linear model. An area of high CPUE was observed in the Yellow and East China seas from...

Geochemical chronologies were constructed from otoliths of adult Pacific bluefin tuna (PBT) to investigate the timing of age-specific egress of juveniles from coastal nurseries in the East China Sea or Sea of Japan to offshore waters of the Pacific Ocean. Element:Ca chronologies were developed for otolith Li, Mg, Mn, Zn, Sr, and Ba, and our assessm...

To examine the habitat usage of adult Pacific bluefin tuna (PBF), electronic tagging was conducted in the Sea of Japan during May and June of 2012-2017. Archival tags were internally implanted and pop-up satellite archival transmitting tags were deployed; data on the horizontal movements and diving behaviours of 36 individual PBF were successfully...

Marine cladocerans are secondary producers in marine neritic ecosystems. To investigate the population dynamics and species-specific habitats of marine cladocerans in the Sea of Japan, marine cladoceran abundance was evaluated in the southern Sea of Japan and the East China Sea-Kuroshio using three mesh-size (0.06, 0.10, and 0.33 mm) plankton nets...

Differences in the reproductive traits of Pacific bluefin tuna Thunnus orientalis (PBF) in the Sea of Japan (SOJ) were investigated to evaluate the reproductive potential in 3 fishing grounds (i.e. northern, central and southern areas). The size distribution of PBF differed among the fishing grounds, with smaller fish (100-130 cm in fork length, FL...

Geochemical chronologies were constructed from otoliths of adult Pacific bluefin tuna (PBT) to investigate the timing of age-specific egress of juveniles from coastal nurseries (natal sites) in the East China Sea or Sea of Japan to offshore waters of the Pacific Ocean. Element:Ca chronologies were developed for otolith Li:Ca, Mg:Ca, Mn:Ca, Zn:Ca, S...

Information on the movements of highly migratory species is important to understand their ecology, including habitat use, population connectivity, and stock structure, to implement appropriate management and conservation measures. The blue shark Prionace glauca (Carcharhinidae) is highly migratory, has a global distribution, and is ecologically and...

We evaluated spatiotemporal dynamics of yellow seabream (YSB) in the East China Sea (ECS) from 1993 to 2018 with a delta-type approach using generalized additive models (delta-GAM). We used catch records from the Japanese bull-trawl fishery and otter-trawl surveys. The delta-GAMs incorporated several explanatory variables and predicted YSB habitats...

To better understand habitats of larval Pacific bluefin tuna (PBT; Thunnus orientalis) in the nursery grounds, the vertical distribution of larval PBT was collected using a 1-m² Tucker trawl and a 3.14-m² ring net at depths of 0, 10, 20, and 30 m during the spawning seasons of 2016 and 2017. Most of the larvae in the Japan Sea (756 of 938 individua...

The conservation and management of sharks requires appropriate information on their biological and habitat characteristics. Data needed for the conservation and management of two dominant demersal shark species in the East China Sea, the spurdogs (Squalus japonicus and Squalus brevirostris), are inadequate. To remedy this, we analysed biological, c...

To quantitatively evaluate the distribution of tuna larvae relative to oceanographic conditions, we conducted investigations off the Nansei Islands in the western North Pacific in June from 2015 to 2017. Five species, namely Pacific bluefin tuna Thunnus orientalis (PBF), yellowfin tuna T. albacares (YFT), skipjack tuna Katsuwonus pelamis (SKJ), fri...

Natal origin of subadult (age-1) Pacific bluefin tuna (PBT, Thunnus orientalis) from the California Current Large Marine Ecosystem (CCLME) was determined using natural tracers in ear stones (otoliths). Age-0 PBT collected from the two known spawning areas in the western Pacific Ocean (East China Sea, Sea of Japan) were used to establish baseline si...

The feeding ecology of Pacific Bluefin tuna (PBT: Thunnus orientalis) larvae collected from two nursery grounds, namely the Japan Sea and the Nansei area (western North Pacific), was evaluated based on gut content analyses using morphological and metagenetic techniques. The PBT larvae were collected at the surface layer (≥30 m depth) in 2016 and 20...

The conservation and management of sharks requires appropriate information on their biological and habitat characteristics. Data needed for the conservation and management of two dominant demersal shark species in the East China Sea, the spurdogs (Squalus japonicus and Squalus brevirostris), are inadequate. To remedy this, we analysed biological, c...

Lipid and fatty acid composition of female Pacific bluefin tuna (PBF, Thunnus orientalis) reproductive and somatic tissues in southwestern North Pacific and Sea of Japan spawning grounds are compared. Total lipid (TL) levels are higher in liver than white muscle tissues. An increased gonadosomatic index (GSI) during the early spawning season coinci...

Isoscapes of stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in pelagic squid and fish were generated using 1968 measured values in the Northwest Pacific Ocean. We then used generalized additive model (GAMs) to assess the explanatory variables that best predicted regional fish and squid δ13C and δ15N values. A total of 453 squid and 1445...

The larval growth of Pacific bluefin tuna (Thunnus orientalis) was compared between two main spawning areas, the Sea of Japan (SOJ) and the western North Pacific (WNP). Growth trajectories indicate that the larval survival depends on their growth in both areas. Until the flexion stage, larvae of the SOJ showed lower growth than those of the WNP, bu...

We investigated the effect of feeding habits on the fatness (length–weight relationship (LW)) and otolith growth of age‐0 Pacific bluefin tuna (PBF) (fork length (FL) of 15.0–29.9 cm) collected off the southwestern Pacific coast of Japan from July to August during 2010–2015. The feeding rate on Clupeiformes (FRc) was substantially influenced by the...

This study compared the growth history of young-of-the-year (YOY) Pacific bluefin tuna (PBF; Thunnus orientalis) from three cohorts (presumably born in the Nansei Islands area and collected in the Pacific coast of Japan, presumably born in the Nansei Islands areas and collected in the Sea of Japan, and presumably born and collected in the Sea of Ja...

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...

A method for the direct preparation of fatty‐acid methyl esters (FAME) was simplified for fatty‐acid analysis of a single fish larva using gas chromatography (GC). The method included the isolation of a larval trunk and drying in a glass vial, followed by saponification of all the contents without prior lipid extraction. Thereafter, the fatty acids...

Harvest control rules (HCRs) and management procedures (MPs) are used after stock assessment to determine the desirable amount of catch to achieve specified management objectives. These rules play a core role in linking the scientific stock assessment and practical fisheries management activities. Robust HCRs with respect to uncertainties are requi...

Appendicularian abundance was investigated at a total of 235 stations over 5 years, from 2011 to 2015, in southwestern Sea of Japan to evaluate potential factors influencing abundance and to understand their effects on the marine ecosystem. Oikopleura longicauda was the dominant appendicularian species, present in 232 samples, and with the highest...

The distribution of small pelagic fish species changes in association with fluctuating stock biomass. We analyzed the spatio-temporal dynamics of Japanese sardine inhabiting the Sea of Japan during periods of stock biomass fluctuation using generalized additive models (GAMs). Logbook data from drift gill net surveys and large- and medium-type purse...

To evaluate long-term changes in reproductive characteristics and maternal effects in Pacific bluefin tuna in the Sea of Japan, we performed histological observations of the most advanced group of oocytes and measured batch fecundity and egg diameter. We sampled 6767 individuals from 1994 to 2015. The main spawning periods were from June to August,...

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:...

Pacific bluefin tuna (Thunnus orientalis) has two spawning grounds, and each is used at different times: May–June in the Nansei Islands of western North Pacific Ocean and July–August in the Sea of Japan. Although previous studies developed body-length based methods to differentiate between individuals originating in each spawning ground, these meth...

Archival electronic tags were internally implanted in 713 age-0 Pacific bluefin tuna (PBF) caught in their nursery waters off the southern coast of Japan and in the East China Sea over an extended study period (1995–2015) to clarify the spatial and temporal variability of their trans-Pacific migration. Two hundred twenty-five of these tagged tuna w...

To evaluate the impact of temporal variation of primary productivity on the recruitment of Japanese sardine (Sardinops melanostictus) in the Sea of Japan, the phenology of sea surface phytoplankton abundance was estimated from 8 day multiple satellite (SeaWiFS, MODIS-Aqua, MERIS, and VIIRS) derived sea surface chlorophyll (SSChl) a concentrations f...

Accurate determination of age is essential for the comprehensive assessment and management of exploited shark populations. Enhancement of growth bands is necessary to accurately and efficiently determine age. However, most traditional techniques do not describe an efficiency of a series of procedures and the detailed protocol for different-sized sh...

The habitat use of Pacific bluefin tuna (Thunnus orientalis; PBF) in nursery waters off the southern coast of Japan was investigated using archival tags over a 3 year study period (2012–2015), and the data were used to examine the free-ranging habitat preferences of PBF and the relationship between their horizontal movements and the path of the Kur...

In the present study, we analysed the stomach contents of 585 bigeye tuna (BET; Thunnus obesus) caught in the Kuroshio–Oyashio transition zone, a high-productivity region in the western North Pacific Ocean, to describe feeding habits and prey size. We identified 46 prey species belonging to 40 genera. Fish otoliths and squid beaks found in stomachs...

The blue shark, Prionace glauca (L.), is one of the most abundant pelagic sharks, and determining their feeding habits is important for understanding the ocean ecosystem. Generally, stomach contents analysis has been used to evaluate its feeding habits; however simply analyzing stomach contents reveals short-term feeding habits. In this study, we e...

Population growth rate, which depends on several biological parameters, is valuable information for the conservation and management of pelagic sharks, such as blue and shortfin mako sharks. However, reported biological parameters for estimating the population growth rates of these sharks differ by sex and display large variability. To estimate the...

Diet compositions of larval Pacific bluefin tuna (PBT) Thunnus orientalis caught in the Sea of Japan during the summers of 2011-2015 were investigated using both microscopic (n = 149) and metagenetic (n = 120) methods to determine the species' prey and feeding habits. The microscopic analysis revealed that prey abundance in gut contents ranged from...

The present study elucidated the length structure and habitat segregation of North Pacific spiny dogfish (SPD) Squalus suckleyi in the Tsugaru Strait of northern Japan. Length–frequency distributions using kernel density estimation were determined for SPD captured by the bottom longline fishery landed at Minmaya from 1999 to 2011 and at Ohma from 2...

Pacific bluefin tuna (PBF), Thunnus orientalis (Temminck and Schlegel, 1844), is highly migratory and capable of traversing large distances throughout the North Pacific Ocean. The majority of spawning activity has been reported only from the Sea of Japan and western parts of the Pacific Ocean. We have conducted larval surveys in these areas since 2...

The blue shark (Prionace glauca) is the most frequently captured shark in pelagic oceanic fisheries, especially pelagic longlines targeting swordfish and/or tunas. As part of cooperative scientific efforts for fisheries and biological data collection, information from fishery observers, scientific projects and surveys, and from recreational fisheri...

The North Pacific spiny dogfish (SPD), Squalus suckleyi, is a commercially exploited shark species that plays an important role in the ecosystem. To elucidate the distribution of the SPD in the North Pacific and to evaluate the effects of sea surface temperature (SST) and prey availability on its distribution, we estimated the probability of SPD pr...

The abundance index (AI) is a representative indicator used to assess the state of fishery resources. Conventional AI is generally calculated by summing the catch per unit of effort (CPUE) weighted by the size of each fishing area. However, CPUE data has many missing values owing to annual changes in operational fishing areas, and this can lead to...

Pacific bluefin tuna (Thunnus orientalis; PBFT) is a highly migratory species, with some individuals migrating between the western Pacific Ocean (WPO) and eastern Pacific Ocean (EPO). In this study, we used stable isotope analysis to identify PBFT that had recently undergone westward transoceanic migration on the Sea of Japan. A total of 155 PBFT i...

Although archival tags have been deployed in Thunnus since the early 1990s, few studies have placed such loggers on the small-size growth stage. In this study, Pacific bluefin tuna (PBT, Thunnus orientalis) 20–26.5 cm in fork length (FL) were fitted with archival tags and released off the southern coastal area of Japan from July to August in 2012,...

The reproductive biology of the blue shark (Prionace glauca) in the western North Pacific Ocean was investigated to contribute to future stock assessments because of limitations of recent studies and the lack of information about the reproductive cycle. Reproductive data were obtained from 490 males (precaudal length (PCL), 33.4–252.0 cm) and 432 f...

The present study used otolith analysis-based body size back-calculation to: (1) evaluate the hypothesis of growth-dependent survival in young Pacific bluefin tuna (PBF; Thunnus orientalis) from the north-western Pacific Ocean; (2) identify critical developmental stages for survival; and (3) compare interannual differences in early growth. To this...

Little is known about the effects of river discharge on the distribution of foraging seabirds at sea. Here, we tracked a pelagic seabird, the streaked shearwater Calonectris leucomelas, breeding on an island in the East China Sea, by using a GPS-PTT to examine how its foraging area was related to the river plume area. In the East China Sea, the Cha...

The Kuroshio–Oyashio transition zone is one of the most important fishing grounds for pelagic fish, including blue shark and swordfish, which are primarily targeted by shallower Japanese longliners. We evaluated the fishing behavior of Japanese longliners based at the Kesennuma fishing port to estimate the standardized catch per unit of effort (CPU...

We examined the reproductive biology of three dominant pseudoceanic myctophids, Diaphus garmani, D. chrysorhynchus, and D. watasei, on the slope region of the East China Sea. Overall, females were more abundant in D. garmani and D. chrysorhynchus, while males were more abundant in D. watasei. The gonadosomatic index (GSI) at 50% sexual maturity of...

Longline surveys have been conducted in the Northwest Pacific Ocean from 2000 to 2014 using chartered commercial longline vessels. Each year, two cruises were conducted offshore of northeastern Japan from mid-April to mid-June. For each longline set during the surveys, onboard scientists collected detailed biological information about the species c...

For multiple-batch-spawning fish species with indeterminate fecundity, income breeding might be more rewarding than capital breeding, because it can fine-tune their reproductive output in terms of maternal condition and offspring survival rate. Although income breeding has been suggested for many small and short-lived pelagic fishes, direct and qua...

Background Electronic tags are increasingly used in the studies of fish, but the attachment of electronic tags may affect their behaviour and physiology. While a number of studies have shown effects of electronic tags on fish health and behaviour, few have examined the effects of thermal conditions on the consequences of electronic tagging. In the...

The bigeye thresher (Alopias supercilious) is occasionally caught as bycatch in pelagic longline fisheries targeting tunas and swordfish. Still, it is one of the least known and studied of all pelagic sharks, which hinders assessment of the status of its populations. As part of an ongoing cooperative program for fisheries and biological data colle...

Size-based food webs analysis is essential for understanding food web structure and evaluating the effects of human exploitation on food webs. We estimated the predator–prey mass ratio (PPMR) of the pelagic food web in the East China Sea and Sea of Japan by using the relationships between body mass and trophic position. Trophic position was calcula...

This study explored optimum sets of coefficients used in the management procedure (MP) currently applied to the fishery stocks in Japan when estimates of the total stock biomass are not available. The MP determines annual allowable biological catch (ABC) every year using the trend of relative stock abundance and the estimated current stock status c...

This paper presents an estimation of growth curves and spatiotemporal distributions of juvenile shortfin mako shark (Isurus oxyrinchus) in the western and central North Pacific Ocean using port sampling data collected from 2005 to 2013. The monthly length compositions show a clear transition of three modes in the size range of smaller than 150-cm p...

Multiple batch spawning over a season should have an advantage for maternal fitness in unpredictable environments, but the manner in which females allocate resources to reproduction is not well understood. We explored the effects of temperature and food availability on reproductive traits in Japanese anchovy Engraulis japonicus using several physio...

The allowable biological catch (ABC) in Japanese fishery management is currently determined by applying harvest control rules, which are categorized into two types depending on whether or not stock-size information is available. We evaluate management procedures (MPs) in data-poor situations using an operating model (OM) based on a production model...

The species of the genus Decapterus are important for fisheries in western Japan, but few in number and reports on their biological characteristics remain limited. This is the first report on the growth and maturation of the roughear scad Decapterus tabl in the East China Sea. The growth model of the roughear scad was estimated as follows: FL t = 3...

Pacific bluefin tuna, Thunnus orientalis, and dolphinfish, Coryphaena hippurus, are temporally sympatric top predators in the north East China Sea. To clarify their vertical habits in relation to the thermocline, we analyzed swimming depth and ambient temperature data for Pacific bluefin tuna that were obtained from animal-borne data-loggers in Apr...

Growth and reproductive characteristics of jack mackerel Trachurus japonicus collected in the East China Sea were determined based on otolith readings and gonad histology, respectively. Translucent and opaque zones on sectioned otoliths were identified and opaque rings counted. Von Bertalanffy growth parameters did not significantly differ between...

Benthosema pterotum is a dominant myctophid in the shelf region of the East China Sea (ECS). They are a key species linking secondary producers and upper trophic levels. We examined the reproductive biology of B. pterotum in the ECS, based on 3065 specimens (10.7–54.8 mm standard length (SL)) sampled during cruises in 1999 and 2004–2009 to enable d...

The feeding ecology of two dominant lanternfishes Diaphus garmani and Diaphus chrysorhynchus was studied in the continental slope region of the East China Sea, off western Kyushu (31-33° N; 128-130° E). Stomach contents of D. garmani were composed mainly of crustacean zooplankton, such as copepods, euphausiids, decapod larvae and amphipods, and als...

The growth and reproductive characteristics of dolphinfish Coryphaena hippurus collected in the waters off western Kyushu from May 2008 to April 2011 were determined based on scale and otolith readings and gonad histological examinations, respectively. Based on annual increments in scales and daily increments in sagittal otoliths, the von Bertalanf...

Acoustic surveys have been conducted for estimating the biomass of commercially important fish (e.g., anchovy, jack mackerel), lanternfish (Diaphus garmani and D. chrysorhynchus), and pearlside (Maurolicus japonicus) in summer in the East China Sea (ECS) since 1997. The biomass of lanternfish and pearlside was 2.26–19.16 times that of commercially...

The YOKO-MARU is newly built last December that is a research vessel belongs to Seikai National Fisheries Research Institute. She equipped the new multibeam echosounder SIMRAD ME70 which is expected to be active in future research. East China Sea is one of important fishing area of small pelagic fishes, sardine, anchovy, chub mackerel, and jack mac...

Environmental changes influence foraging behavior for most animals. Dolphinfish, Coryphaena hippurus, are epipelagic predators and have a cosmopolitan tropical to warm-temperate (>20°C) distribution. We simultaneously obtained the ambient temperature and the foraging behavior (i.e., swimming speed, depth and tailbeat acceleration) of dolphinfish, u...

We analyzed the biological characteristics such as growth and maturation of round herring Etrumeus teres in the East China Sea. Von Bertalanffy's growth curve was calculated based on monthly size frequency distributions from 1997 to 2009, and the estimated growth formula was BL m=244.8[1-exp {-0.10(m-0.55)}](r 2=0.92, p <0.01), where BL m is body l...

Acoustic surveys were conducted from 2002 to 2006 in the East China Sea off the Japanese coast in order to develop a quantitative classification typology of a pelagic fish community and other co-occurring fishes based on acoustic descriptors. Acoustic data were postprocessed to detect and extract fish aggregations from echograms. Based on the exper...

Growth and reproductive characteristics of gold striped amberjack Seriola lalandi collected in the waters off western Kyushu from April 2003 to March 2008 were determined based on vertebral centrum readings and gonad histology, respectively. Translucent and opaque zones on vertebral centrum were identified, and the number of opaque rings counted. V...

Growth and reproductive characteristics of shortfin scad Decapterus macrosoma and mackerel scad D. macarellus collected in the waters off southern Kyushu were determined based on otolith readings and gonad histology, respectively. Translucent and opaque zones on sectioned otoliths were identified, and the number of opaque rings counted. Von Bertala...