Genetic divergences and hybridization within the complex.

The complex includes three sympatric species (, viz , and ) with clear ecomorphological differences, albeit incomplete reproductive isolation. The presence of putative morphological hybrids (PMH) with plausibly higher fitness than the parent species indicates the need to confirm whether hybridization occurs within the complex. In this sense, we assessed the dynamics of genetic divergence and hybridization within the species complex using a panel of 10 microsatellite loci, and sequences of the mitochondrial control region (D-loop) and the intron-free rhodopsin (RH1) gene.

Redescription and molecular characterization of Mothocya parvostis Bruce, 1986 (Crustacea: Isopoda: Cymothoidae) parasitic on Japanese halfbeak, Hyporhamphus sajori (Temminck & Schlegel, 1846) (Hemiramphidae) with Mothocya sajori Bruce, 1986 placed into synonymy.

Two species of Mothocya have previously been recorded from Hyporhamphus sajori: M. parvostis Bruce, 1986 and M. sajori Bruce, 1986.

Molecular and Morphological Characterizations of the Fish Parasitic Isopod (Crustacea: Cymothoidae) Parasitizing Optional Intermediate Hosts: Juveniles of the Cobaltcap Silverside and Yellowfin Seabream .

(Isopoda: Cymothoidae) is a parasitic crustacean that infests the opercular cavities of fishes. Its main final host is the Japanese halfbeak, . However, also infests the black sea bream, , as an optional intermediate host.

Quatrefoil light traps for free-swimming stages of cymothoid parasitic isopods and seasonal variation in their species compositions in the Seto Inland Sea, Japan.

Cymothoid parasitic isopods infest a wide range of fish of different taxa living in marine, brackish, and freshwater environments. Most research on the reproductive season of Cymothoidae has been done by collecting or monitoring host fish afflicted with cymothoid parasites. However, collecting ecological data on cymothoid species that infest non-commercial or endangered fishes is complex and challenging.

Spawning time of black sea bream Acanthopagrus schlegelii, related to underwater photoperiodism in oyster farms.

The embryonic development times, spawning timing and hatching rates of the black sea bream Acanthopagrus schlegelii were examined to investigate the potential effect of seawater temperature, tides and photoperiod on the reproductive rhythm of this species in Hiroshima Bay, Japan. Low temperatures decreased hatching rates and extended the hatching time, and the minimum temperature threshold for hatching was 15°C. Back-calculated spawning times indicated that the peak of spawning occurred just before sunset and the reduction in diurnal light intensity around the oyster rafts acted as a trigger for spawning.

The complete mitochondrial genome of (Perciformes, Sparidae) from Iriomotejima Island, Okinawa, Japan.

The Pacific seabream, , is a commercially valuable resource for fisheries around the West Pacific Ocean countries. Although the phylogenetic position of the within the genus changes by the differences in the target gene regions or fish sampling locations, the genetic information of the species is quite limited. In this study, the complete mitochondrial genome of from Iriomotejima Island, Okinawa, Japan was determined.

Oyster farms are the main spawning grounds of the black sea bream in Hiroshima Bay, Japan.

Understanding the anthropogenic impact of oyster farms is essential for the management and conservation of marine fishes. In Japan, Hiroshima Bay is the region with the most intense oyster farming and thus suitable to study the impact of these farms. Here, we surveyed spherical planktonic eggs of the black sea bream , one of the most abundant fish in the Bay.

The role of the isolation of the marginal seas during the Pleistocene in the genetic structure of black sea bream (Bleeker, 1854) in the coastal waters of Japan.

The black sea bream (Bleeker, 1854) is a commercially important species in Japanese waters. Assessing its population structure is essential to ensure its sustainability. In the Northwestern Pacific, historical glacial and interglacial periods during the Pleistocene have shaped the population structure of many coastal marine fishes.

Infestation of the Parasitic Isopod on Juveniles of the Black Sea Bream as an Optional Intermediate Host in Hiroshima Bay.

In Hiroshima Bay, parasitic isopods of the genus infest the black sea bream (Bleeker, 1854) and the Japanese halfbeak (Temminck and Schlegel, 1846), two fish species that are abundant and commercially important in the Seto Inland Sea of Japan. Immature and mature individuals can infect both juveniles and adults of , while immature are known to parasitize juveniles of ; i.e.

Genus-level phylogeny of cephalopods using molecular markers: current status and problematic areas.

Comprising more than 800 extant species, the class Cephalopoda (octopuses, squid, cuttlefish, and nautiluses) is a fascinating group of marine conchiferan mollusks. Recently, the first cephalopod genome (of ) was published, providing a genomic framework, which will enable more detailed investigations of cephalopod characteristics, including developmental, morphological, and behavioural traits. Meanwhile, a robust phylogeny of the members of the subclass Coleoidea (octopuses, squid, cuttlefishes) is crucial for comparative and evolutionary studies aiming to investigate the group's traits and innovations, but such a phylogeny has proven very challenging to obtain.

Individual identification of goldfish from eye morphology: the eye mark method.

We developed an individual identification method for goldfish based on morphological variation of the iris. Each goldfish has a few dark lines (eye marks) in the rostral and caudal portion of the iris, which are blood vessels underneath the silvery reflective layer. Through the blood vessels and the locally thin reflective layer, the pigment cell layer is partially visible as a dark line.

Eleven novel polymorphic microsatellite Loci for oval squid Sepioteuthis lessoniana (Shiro-Ika type).

The oval squid Sepioteuthis lessoniana is one of the most economically important squid species in Japan; however, its population structure is poorly understood due to the lack of hypervariable markers. Such information is critical for managing sustainable fisheries, as well as for ensuring the existence of wild S. lessoniana stocks.

Comparisons of internal behavior after exposure to Flavobacterium psychrophilum between two ayu (Plecoglossus altivelis altivelis) strains showing different cumulative mortality to bacterial cold water disease.

Bacterial cold water disease (BCWD) in ayu (Plecoglossus altivelis altivelis) has a serious impact on aquaculture and fisheries. There is known to be a significant difference among ayu strains with regard to mortality caused by BCWD. In this study, the immune response of different ayu strains against Flavobacterium psychrophilum infection was observed.

Influence of host habitat on the occurrence of gill monogeneans Pseudodactylogyrus spp. on wild Japanese eels Anguilla japonica.

With technological improvements in otolith microchemical analysis, the flexible use of habitat from coastal marine to fresh waters has been discovered in Japanese eels Anguilla japonica. We examined the occurrence of 3 congeneric gill monogeneans-Pseudodactylogyrus anguillae, P. bini, and P.

The effects of 2-bromopalmitate on the fatty acid composition in differentiating adipocytes of red sea bream (Pagrus major).

To determine whether external factors affect the adipogenic function of fish adipocytes, the effects of 2-bromopalmitate (a PPAR agonist) on the fatty acid composition in differentiating adipocytes of red sea bream were investigated in vitro. In the presence of 2-bromopalmitate, the red sea bream adipocytes were differentiated and the effects on the fatty acid composition and the adipogenic gene expression were analyzed. With the level of 2-bromopalmitate, the content of 16:1n-7, a delta-9 desaturation product, increased in association with the increase in a stearoyl CoA desaturase (SCD) gene expression level while the triglyceride accumulation was not affected.

Molecular characterization of peroxisome proliferator-activated receptors (PPARs) and their gene expression in the differentiating adipocytes of red sea bream Pagrus major.

To investigate the molecular mechanism of fish adipocyte differentiation, the three subtypes of PPAR genes (alpha, beta and gamma) were characterized in a marine teleost red sea bream (Pagrus major). The primary structures of red sea bream PPARs exhibited high degrees of similarities to their mammalian counterparts, and their gene expression was detected in various tissues including adipose tissue, heart and hepatopancreas. During the differentiation of primary cultured red sea bream adipocytes, three PPARs showed distinct expression patterns: The alpha subtype showed a transient increase and the beta gene expression tended to increase during adipocyte differentiation whereas the gene expression level of PPARgamma did not change.

Molecular characterization of lipoprotein lipase, hepatic lipase and pancreatic lipase genes: effects of fasting and refeeding on their gene expression in red sea bream Pagrus major.

To investigate the nutritional regulation of lipid metabolism in fish, molecular characterization of lipases was conducted in red sea bream Pagrus major, and the effects of fasting and refeeding on their gene expression was examined. Together with data from a previous study, a total of four lipase genes were identified and characterized as lipoprotein lipase (LPL), hepatic lipase (HL) and pancreatic lipase (PL). These four lipase genes, termed LPL1, LPL2, HL and PL, share a high degree of similarity.

Effects of insulin, triiodothyronine and fat soluble vitamins on adipocyte differentiation and LPL gene expression in the stromal-vascular cells of red sea bream, Pagrus major.

Various kinds of hormones including insulin, triiodothyronine (T(3)) and fat-soluble vitamins have been proposed as mediators of adipocyte differentiation in mammals. To investigate the factors which are responsible for fish adipocyte differentiation, we developed a serum-free culture system of stromal-vascular cells of red sea bream adipose tissue and examined the effects of bovine insulin, T(3), and fat-soluble vitamins (all-trans retinoic acid, retinyl acetate and 1,25-dihydroxyvitamin D(3)) on the differentiation-linked expression of the lipoprotein lipase (LPL) gene. As assessed by the increase in LPL gene expression after 3 day cultivation, like in mammalian adipocytes, insulin enhanced the adipocyte differentiation in a concentration-dependent manner.