We examined specimens from the winter–spring cohort of the neon flying squid Ommastrephes bartramii caught off the coast of northeastern Japan in early summer and the following winter for mantle length, sex, maturity, and age to determine their hatching dates as well as their growth and migration patterns. Squid specimens were collected with a research driftnet in July 2018 in the northwestern Pacific

Male 5-week-old F344 rats were fed four types of experimental diet with different Ca and protein sources for 30 days, and the effect of feeding retort-treated herring bone on Ca absorption and bone metabolism were examined. The experimental diets were as follows: AIN-93G (casein-based standard breeding diet) containing 0.5% Ca from CaCO3 (C); modified AIN-93G containing 0.25% Ca from CaCO3 (L); retorted

The presence and status of harmful algal blooms (HABs) in Japan are reviewed, revealing a decrease in red tides; however, toxic blooms are found to be increasing in western Japan. Environmentally friendly control strategies against HABs are also compared with integrated agricultural pest management. Very high densities (105–108 CFU/g) of algicidal and growth-inhibiting bacteria were found in biofilm

Sustainable conservation management of chum salmon in Japan requires ecological information on wild fish. This study investigated the spawning timing in a nonstocked river and the occurrence of wild fry in a surf zone in Niigata Prefecture. Most redds were observed from mid-October to mid-December on riverbeds having stream water of variable but cold temperatures above 5.4 °C. Chum salmon fry (< 41 mm)

Protease inhibitors are widely distributed in the skin mucus of fish. The pufferfish, family Tetraodontidae, has high antitryptic activity among fish. In this study, we isolated and characterized a protease inhibitor from the skin mucus of the pufferfish Takifugu rubripes. The inhibitor termed T. rubripes trypsin inhibitor 2 (TRTI-2) is a serine protease inhibitor and specifically inhibits trypsin

We validated the daily formation of increments in otoliths of yellow goosefish Lophius litulon using reared individuals to examine the growth in the field. Single, round-shaped core structures were observed in 41% of sagittae and in 73% of the lapilli. Therefore, lapillar otoliths were used for further observations of daily increment analysis. The lapillus radius of newly hatched larvae was 15.0 ± 1

The hydrolysate of Oncorhynchus keta (chum salmon) milt was found to exhibit strong inhibitory activity against dipeptidyl peptidase-IV (DPP-IV), and the hypoglycaemic effect of these salmon milt peptides (SMPs) was confirmed using oral starch tolerance tests in Sprague–Dawley rats. Specifically, the oral administration of SMPs at a dose of 300 mg/kg body weight for 1 week resulted in a significant

During the induction of Japanese eel maturation, administering maturation-inducing steroids (MIS) or their precursors at an inappropriate maturational status is a major cause of poor egg quality. In this study, we investigated the feasibility of controlling oocyte maturation progress by rearing in cold and warm water to manipulate the timing of MIS administration. Mature females with oocytes at the

The process of salt permeation into fish meat was studied using magnetic resonance imaging (MRI) and salt diffusion simulation. MRI measurements of a fish body rubbed with salt powder were carried out, using various echo times to calculate the relaxation time 1H T2 and construct a 1H T2 map. The 1H T2 values were measured for fish fillets immersed in various salt concentrations to obtain the relationship

Sustainable aquaculture of the Japanese eel Anguilla japonica requires an understanding of the physiological conditions of the fish under culture conditions. Therefore, we examined the effects of tentative stressors such as background color and rearing density on stress-related hormones in juvenile Japanese eel. In Experiment 1, fish were divided into white- or black-coated tanks and reared for 35 days

Six graded levels of dietary alfalfa Medicago falcata L. powder (0, 5, 10, 15, 20 and 25 g/kg diet, respectively) were fed to Lateolabrax japonicus (initial body weight: 11.41 ± 0.06 g; initial body length: 10.33 ± 0.12 cm) in triplicate groups for 4 weeks in a flow-through system to investigate the effects of alfalfa powder on the growth performance, nonspecific immunity and digestive enzyme activity

We collected samples of Pacific saury Cololabis saira (249–331 mm in knob length; ages 0 and 1) in the North Pacific Ocean from 154°E to 165°W during their northward migration in the early summers of 2013, 2014, and 2015, and measured the stable nitrogen and carbon isotope ratios (δ15N and δ13C) of their muscle tissues. A hierarchical cluster analysis based on δ15N and δ13C yielded three groups (G1–G3)

Temperature shock is a major natural cause of mass mortality of global fish. Nile tilapia Oreochromis niloticus, one of the most widely cultured species, with high resistance against severe environmental conditions, is also affected by rapid temperature changes. This research was conducted to investigate histopathological changes and oxidative stress in O. niloticus in response to temperature shock

We examined the combined effects of fasting in freshwater and water temperature during the transition from freshwater to seawater on growth/metabolic parameters in juvenile chum salmon Oncorhynchus keta. Juveniles of 1 g in freshwater were first subjected to a 5-day fasting period at 10 or 5 °C, acclimated to either 10 or 5 °C seawater and fed ad libitum for 30 days. Control fish were transferred from

Standardized catch per unit effort (CPUE) is frequently used to represent annual fish-stock abundance trends. In multispecies fisheries, the catchability coefficient differs depending on the target strategy. Consideration of the target strategy in CPUE standardization is therefore crucial in improving the accuracy and precision of annual CPUE estimates. This study focuses on the potential of a finite

Japanese Spanish mackerel Scomberomorus niphonius is a target species for stocking, but its biological characteristics at the juvenile stage are not well understood. Here, we investigated the high-temperature and starvation tolerances of hatchery-reared juveniles in captivity. We used juveniles of approximately 40 mm standard length, the size of juveniles released into the field. The upper incipient

The age, growth, and reproductive biology of the five-lined snapper Lutjanus quinquelineatus was estimated using 709 specimens (44.2–197.7 mm) collected from November 2012 to November 2014 around Okinawa-jima Island, southern Japan. The oldest age estimated by sectioned otoliths and maximum standard length were 24 years and 192.1 mm for females and 27 years and 197.7 mm for males. The relationship

This study identified the location and geographical characteristics of rivers where Arctic lamprey Lethenteron camtschaticum were captured in the past and present in Japan and evaluated the effectiveness of the local ecological knowledge (LEK) held by inland fishers for estimating species distribution. We collected information about fishery harvests for Arctic lamprey from fishery statistics published

Seasonal variations of extractive components in mussels cultured in Hiroshima Bay were investigated. Meat yield was maintained at approximately 30%, except for in December and January. Glycogen content from June to August was significantly higher than that from November to January. Glutamic acid and aspartic acid showed no seasonal variation. Taurine and glycine indicated different seasonal changes

Chum salmon myofibrillar protein (Mf) digested by pepsin-trypsin (dMf) was conjugated to alginate oligosaccharide (AO) through the Maillard reaction between the lysine residues in the dMf and the reducing end-groups of AO. The dMf-AO conjugate strongly suppressed the production of inflammatory cytokines, particularly tumor necrosis factor-α and interleukin-6, in lipopolysaccharide-stimulated murine

Balenine is one of the endogenous imidazole dipeptides. It is composed of beta-alanine and 3-methyl-l-histidine, which exist mainly in the muscles and the brain. The exact biological properties of balenine are still not well known, although the antioxidant activity of carnosine, another imidazole dipeptide, is known. In this study we investigated whether balenine exhibits antioxidant activity. It was

The spawning area of the Japanese eel is located at the southern part of the West Mariana Ridge in the western North Pacific, but their spawning events have not been observed. To further understand Japanese eel spawning ecology, an interdisciplinary research survey by the R/V NATSUSHIMA (NT14-09, 14 May–4 June 2014) was conducted to detect spawning sites based on the seamount, salinity front, new moon

Evaluation of the molting stage of crustaceans is essential for studying their mating behavior because of molt-dependent changes in their behavior. For example, in species in which females mate just after molting, sexually mature premolt females are ready for courtship and postmolt females are ready for copulation. Non-invasive methods of evaluating molt stage are essential in studies of molt-dependent

Artificial light plays an important role in commercial light fisheries as a means to attract fish, such as the Pacific saury and squid. To gain an insight into the optimal allocation of light-emitting diode (LED) fishing lamps in the Pacific saury fishery, we present a mathematical illumination model to describe the illumination characteristics of LED modules installed at different angles. The validity

Invertebrates change the metabolite concentrations in their bodies to adapt to environmental salinity. The kuruma shrimp Marsupenaeus japonicus is one such invertebrate. It lives in coastal areas and is also known to change free amino acid concentrations depending on environmental salinity. To examine the relationship between the concentrations of metabolites, including amino acids, in the kuruma shrimp

A correction to this paper has been published: https://doi.org/10.1007/s12562-021-01502-z

A correction to this paper has been published: https://doi.org/10.1007/s12562-021-01503-y

A correction to this paper has been published: https://doi.org/10.1007/s12562-021-01504-x

A correction to this paper has been published: https://doi.org/10.1007/s12562-021-01507-8

A correction to this paper has been published: https://doi.org/10.1007/s12562-021-01505-w

Outbreaks of bacterial cold-water disease (BCWD), caused by Flavobacterium psychrophilum, are widespread in Japan, especially among ayu Plecoglossus altivelis. There are few investigations of F. psychrophilum in river water, and its seasonal distribution has not been clarified. We aimed to identify the spatiotemporal dynamics of F. psychrophilum and ayu to provide information that is useful for establishing

China (herein referred as China’s mainland, and excluding Hong Kong, Macau and Taiwan) is the largest contributor to global seafood production. While China’s marine fisheries have been extensively documented, there is a gap in systematically quantifying production of its marine fisheries and the different challenges confronting them at the provincial level. We addressed this gap in spatial detail by

Accurately predicting the price of exported fishery products is an important task for fisheries because it will enable market trends to be determined, leading to the development of high-quality fishery products. In this study, we predicted prices in selected base periods (2, 3, 6, and 12 months) to investigate how historical data influenced the Vietnamese export price. A dataset (from May 1995 to May

A correction to this paper has been published: https://doi.org/10.1007/s12562-021-01506-9

The amphipod Sunamphitoe namhaensis grazes on seedlings of Sargassum horneri in culture. To exterminate S. namhaensis, we immersed them in seawater with dissolved carbon dioxide—a treatment used previously to remove copepods in cultures of abalone and sea cucumber. Experiments were conducted under different CO2 (aq) concentrations and for different lengths of time. Amphipod mortality was 100% following

Understanding the role different habitats play in the life histories of fishes is important for the development of holistic aquatic ecosystem management plans. We used otolith trace element analysis to reconstruct the life history of estuarine triplefin Forsterygion nigripenne and infer its habitat use. Analysis of otoliths using laser ablation inductively coupled plasma mass spectrometry showed an

The Silond catfish Silonia silondia, locally known as Nga Myin Yinn, is a commercially important fish in Myanmar; however, fundamental knowledge of its population structure is insufficient. Specimens caught in different regions of the Ayeyarwady River, the basin of which is the country’s largest, from 2017 to 2019 were used to sequence two mitochondrial (mt)DNA genes, cytochrome b and ATPase 6/8, for

Here, we investigated the effect of dietary cysteic acid on the growth performance, sulfur amino acid content, and gene expression levels of taurine-synthesizing enzymes, growth hormone (GH), and insulin-like growth factor 1 (IGF-1) in Japanese flounder Paralichthys olivaceus. Juvenile flounder (0.9 g) were fed one of four diets for 30 days: with 0.25, 0.5, or 1.0% cysteic acid (C0.25, C0.5, C1.0)

We compared the shapes and catches of two trawl nets having differing headrope and groundrope configurations based on paired tow data collected by two research vessels (Yoko Maru and Kumamoto Maru) in the East China Sea. According to the paired data, the vertical opening of the net was significantly higher on the Yoko Maru, which employed a headrope kite, than the Kumamoto Maru, which uses floats on

Hemicentrotus pulcherrimus in the Tohoku area is not utilized as a fishery product because the ovaries have a bitter taste almost all year. To discover the cause, we compared the annual reproductive cycles and ovarian accumulation of a bitter amino acid, pulcherrimine, in H. pulcherrimus collected at Mikuni (Fukui Prefecture), where it is fished in summer, and Iwaki (Fukushima Prefecture), where it

Temperate eels are well known for partial migration where contingents may remain settled in marine habitats or move between seawater and brackish and freshwater habitats during their sub-adult life. This behaviour is less described in tropical Anguillid eels, particularly as it relates to salinity preference, habitat selection, and growth. In this study, glass eels Anguilla marmorata were collected

Seasonal changes in habitat use in terms of depth and temperature were estimated for Japanese flounder Paralichthys olivaceus from the Pacific coast of northeastern Japan from 2006 to 2008, using data from trawl and gillnet fisheries logbooks, to which we assigned monthly estimates of bottom temperature. Estimated distributions of flounder for depth and temperature were validated by actual depth and

The residence and movement patterns of the marbled flounder Pseudopleuronectes yokohamae were investigated around a spawning ground located off the coast of Nagasaki point, southern Suo Nada, Seto Inland Sea, Japan. Twenty marbled flounder (9 females and 11 males) tagged with ultrasonic transmitters were released on November 29, 2017, before the peak spawning season (peak spawning season: mid–late

With a decrease in the domestic catches of Ruditapes philippinarum, suspended culture is a potential approach to increase its production. We investigated the establishment of suspended clam culture in Suttsu fishing port, Hokkaido. Cages accommodating 100 clams (mean shell length 28 mm) were suspended in the “stocking area” at the back of the port and the “fairway area” at the center of the port. Rearing

Green tides caused by Ulvales group macroalgae have been reported from many eutrophic waters around the world. The asari clam Ruditapes philippinarum is an important fisheries resource in Japan and co-exists in coastal waters with Ulvales macroalgae. This study examined a possible impact of fresh Ulva fronds on the growth of juvenile, adult, and spat asari clams by conducting rearing experiments. Significant

To investigate the influence of parasitism of the copepod Pennella sp., which belongs to the family Pennellidae, on mortality in the Pacific saury Cololabis saira, we examined the seasonal changes in the following indices: prevalence (%; no. of infected fish × 100/no. of examined fish), mean intensity (total no. of infected Pennella sp./no. of infected fish), relative intensity (total no. of infected

The Japanese eel Anguilla japonica is a prominent and highly valued species in the aquaculture industry in Japan. Sex determination and sex differentiation in eels are significantly affected by environmental factors; however, the molecular mechanisms involved in sex differentiation in eels are largely unknown. In this study, to investigate the gonadal expression profiles of sex-specific genes during

Sepioteuthis lessoniana is a crucial squid species in fisheries and plays a critical role in marine ecosystems. At least two taxa of the squid species have been identified in the waters around Japan; however, the basic biological information of these taxa is limited. In this study, the taxa composition of Sepioteuthis was examined using molecular evidence, and the life-history traits and statolith

To explore the gillnet selectivity for swimming crab Portunus trituberculatus , six mesh sizes (100, 110, 120, 130, 140 and 150 mm) were tested to determine the optimal mesh size for swimming crab. The experiments were conducted in the traditional area for fishing crab in the East China Sea from 25 to 29 July 2018. Four kinds of selectivity curves were used for fitting, and the maximum likelihood method

In this study, the interannual variations of ichthyoplankton assemblages in the Taiwan Strait (TS) during the winters of 2007–2013 were determined. The cold China Coastal Current (CCC) and Mixed China Coastal Water (MCCW) intruded into the TS and impinged with the warm Kuroshio Branch Current (KBC) with annual variations. Consequently, the ichthyoplankton community in the TS was mainly structured into

To elucidate the dynamics of oxidative stress in fish, it is necessary to know the concentration of superoxide anions as a precursor to various reactive oxygen species in the living body. Superoxides are unstable radicals, disappearing within a few seconds, which makes it challenging to measure them using conventional methods. We describe herein the development of a biosensor that can rapidly quantify

Estrogenic endocrine-disrupting chemicals are an increasing social concern, as they can reduce the reproductive activity of wildlife. The present study aimed to clarify the long-term effects of estradiol-17β (E2) on male reproductive activity in goldfish. Sexually mature male goldfish were implanted with a silicone capsule containing E2, and kept for 14 weeks or 15 weeks. The reproductive activity

Our ultimate aim is to establish a small-bodied surrogate broodstock (e.g., mackerel) that produces functional gametes of the Pacific bluefin tuna Thunnus orientalis using xenogeneic germ cell transplantation. To accomplish this goal, we need to be able to sequentially trace transplanted donor cells in recipients. Here we succeeded in identifying two monoclonal antibodies that could specifically recognize

The solitary European sea squirt Ascidiella aspersa was introduced to northern Japan, causing dense coverage of the aquacultured Japanese scallop Mizuhopecten yessoensis . There are concerns that allelopathy by the sea squirt will suppress the growth of the scallop. Herein, we studied the allelopathic and defensive potential of A. aspersa using hemolytic assay. An alkyl sulfate, viz. 3,7,11,15-tet

The cleavage pattern of a vertebrate’s embryo is either holoblastic (complete) or meroblastic (partial). Sturgeon and other basal bony fishes represent a transition of the cleavage pattern. To understand the transition, it is essential to develop an effective technique for the inhibition of specific blastomere cleavage. So far, various studies have demonstrated that diatom-derived polyunsaturated aldehyde

We examined the effects of tank color and stocking density on the growth of spotted halibut ( Verasper variegatus ) under a green light-emitting diode (LED). Fish reared for 40 days under a green LED (10 μmol m –2 s –1 at the water surface) grew faster than those reared under a white LED, irrespective of tank color (white or black). Green light promoted higher growth than indoor room light when fish

Cytokines are low molecular weight glycoproteins involved in the regulation of the immune system, and more than 100 cytokines have hitherto been identified in humans. Cytokines similar to those found in humans have also been found in fish. The innate immune response of fish can be examined by using cytokines as markers. We developed a multiplex reverse transcription–polymerase chain reaction assay

Leptocephalus larvae have transparent bodies with tubular intestines that usually lack identifiable food items when they are collected, so mystery has surrounded efforts to determine what they feed on. Artificially spawned and reared first-feeding larvae were found to be highly selective in what they would eat, but they would consume rotifers and eventually ate specially formulated diets that contained

Snow trout Schizothorax labiatus constitute a significant part of the diet of large human population of colder regions of the Indian Himalayan subcontinent, and are also important for local livelihoods there. In the present study, the hematological and serum biochemical parameters of S. labiatus were examined with respect to sex and season. Hemoglobin (Hb) concentration, red blood cell (RBC) count

Bristle patches on the carapace behind the eyes were found for the first time in both males and females of the four species of mud crab Scylla spp. Electrocardiography revealed that the bristle patches of Scylla paramamosain were sensitive to touch (with a glass capillary) but not to chemical stimulation (with sugarcane juice). To elucidate the function of these touch signals, the courtship behaviour