Acanthogobius Flavimanus Research Articles

섬진강 하류역에 서식하는 어류의 군집구조 및 공간 규모에서 종 다양성

A biological assessments of fish community structure were carried out in the lower reach of Seomjin River from May 2009 to November 2010. The collected fish from the six surveyed sites were 63 species belonging to 24 families, and 10 orders. Although species was different depending on sites, the numbers of individuals were not shown significance on sites. Locational dominant species were different. For example, the dominant species on May were Zacco platypus at W-1, Zacco temminckii at W-2, Acanthogobius flavimanus at W-3 and W-4, and Leiognathus nuchalis at W-5 and W-6. There is no seasonal differences in species. Species diversity was the best up to 2.64 on May at W-1 from 1.33 on November at W-6. As a result of an analysis about environmental factors for the numbers of fish species and individuals in each surveyed sites, the most effective groups were DO, BOD, and COD. The proportional difference was high on May than November between transient and asymptotic projections for population size and population growth rate for simulations starting at the current or theoretical stage distribution.

An Indigenous Case of Intestinal Capillariasis with Protein-Losing Enteropathy in Korea

We encountered an indigenous case of intestinal capillariasis with protein-losing enteropathy in the Republic of Korea. A 37-year-old man, residing in Sacheon-si, Gyeongsangnam-do, admitted to the Gyeongsang National University Hospital (GNUH) due to long-lasting diarrhea, abdominal pain, anasarca, and weight loss. He recalled that he frequently ate raw fish, especially the common blackish goby (Acanthogobius flavimanus) and has never been abroad. Under the suspicion of protein-losing enteropathy, he received various kinds of medical examinations, and was diagnosed as intestinal capillariasis based on characteristic sectional findings of nematode worms in the biopsied small intestine. Adults, juvenile worms, and eggs were also detected in the diarrheic stools collected before and after medication. The clinical symptoms became much better after treatment with albendazole 400 mg daily for 3 days, and all findings were in normal range in laboratory examinations performed after 1 month. The present study is the 6th Korean case of intestinal capillariasis and the 3rd indigenous one in the Republic of Korea.

Length-weight relationships for 14 fish species of the Suer River estuary in southern Korea

Summary Length–weight relationships were estimated for 14 species belonging to 13 fish families from the Suer River estuary, Korea. These 14 species are: Callionymus valenciennei, Konosirus punctatus, Conger myriaster, Cynoglossus joyneri, Tribolodon hakonensis, Thryssa hamiltonii, Acanthogobius flavimanus, Paratrypauchen microcephalus, Hexagrammos agrammus, Nuchequula nuchalis, Pseudopleuronectes yokohamae, Pennahia argentata, Sillago japonica and Takifugu niphobles. Between April 2009 and January 2010, samples were caught by commercial trawl net at depths of <20 m. Estimates for parameter b of the length–weight relationship (W = aLb) ranged between 2.510 and 3.149.

Molecular Phylogeny and Host Specificity of the LarvalEustrongylides(Nematoda: Dioctophmidae) From Freshwater Fish in China

The nematodes Eustrongylides spp. collected from different fish species in China were examined for their intra- and interspecific evolutionary variations using the molecular markers mitochondrial cytochrome oxidase c subunit 1 (COI) gene and internal transcribed spacer (ITS) rDNA regions. The phylogenetic analysis indicated that Eustrongylides species are divided into 3 well-supported clades. The ITS divergence between the clades suggested that clades 2 and 3 might represent the same species, whereas clade 1 represent another cryptic species. The host specificity of these nematodes was analyzed according to prevalence data, host range, and phylogenetic information. Clade 1 was found in 4 fish species, i.e., Odontobutis obscurus, Silurus asotus, Culter mongolicus, and Acanthogobius flavimanus, but was predominant in the 2 perciform species, O. obscurus and A. flavimanus. Clade 2 was found in 3 fish species, Monopterus albus, Channa argus, and Channa asiatica, but was predominant in M. albus, reported to feed primarily on oligochaetes, the first intermediate host of Eustrongylides sp. Clade 3 was found in 9 species, but its low prevalence suggests accidental infection in all species. Although the larval nematode presented low host specificity, it exhibited some host preference.

Infection Status of Estuarine Fish and Oysters with Intestinal Fluke Metacercariae in Muan-gun, Jeollanam-do, Korea

The source of human infection with intestinal flukes was surveyed in estuarine fishes, including the dotted gizzard shad, common sea bass, common blackish goby, redlip mullet, black sea bream, and oyster collected from Muan-gun, Jeollanam-do, Korea during August and September 2007. Collected fishes and oysters were artificially digested in pepsin-HCl solution and examined under a stereomicroscope. In 36 shads (Konosirus punctatus) and 20 basses (Lateolabrax japonicus) examined, Heterophyopsis continua metacercariae were found in 58.3% and 100%, and their average numbers were 12.0 and 6.3 per infected fish, respectively. In 34 gobies (Acanthogobius flavimanus) examined, metacercariae of H. continua were detected in 79.4%, Stictodora lari in 97.1%, and Acanthotrema felis in 92.1%, and their average numbers were 45.8, 189.3, and 235.3 per infected fish, respectively. In 37 redlip mullets (Chelon haematocheilus), Heterophyes nocens metacercariae were found in 56.8%, Pygidiopsis summa in 94.6%, and Stictodora fuscata in 45.9%, and the average metacercarial densities were 17.4, 31.3, and 35.1 per infected fish, respectively. In 30 black sea breams (Acanthopagrus schlegeli) and 45 oysters (Crassostrea gigas) examined, no metacercariae were detected. From the above results, it has been confirmed that the dotted gizzard shad, common sea bass, common blackish goby, and redlip mullet from Muan-gun, Jeollanam-do, Korea are infected with the metacercariae of heterophyid flukes.

Redescription of the fish parasite Nerocila japonica Schioedte &amp; Meinert, 1881 (Crustacea: Isopoda: Cymothoidae), with comments on previous records of N. acuminata in Japanese waters

Nerocila japonica Schioedte & Meinert, 1881 is redescribed based on the holotype and specimens from various localities in Japanese waters. The following fishes are recorded as new hosts: Tribolodon hakonensis (Cyprinidae), Mugil cephalus, Liza affinis, Chelon haematocheilus (Mugilidae), Lateolabrax japonicus, L. latus (Lateolabracidae), Acanthopagrus latus, A. schlegelii schlegelii (Sparidae), Rhyncopelates oxyrhynchus (Terapontidae), Ditrema viride, D. temminckii temminckii (Embiotocidae), Chaenogobius gulosus, Acanthogobius flavimanus (Gobiidae), Pseudolabrus sp. (Labridae) and Aluterus monoceros (Monacanthidae). Specimens previously recorded as 'Nerocila acuminata' from Toyama Bay (the Sea of Japan) were examined, when available, and re-identified as N. japonica. As there has been no reliable record of N. acuminata Schioedte & Meinert, 1881 from off Japan, reports of this species in Japanese waters are considered to represent N. japonica.

Fish assemblages of interior tidal marsh channels in relation to environmental variables in the upper San Francisco Estuary

Tidal marsh wetlands represent critical habitat for many estuarine fishes and are particularly important to conserving and restoring native and at-risk species. We describe the seasonal and regional variation in the composition and abundance of fishes in interior tidal marsh channels in the upper San Francisco Estuary (SFE), and relate these to variation in environmental conditions. Fish were sampled quarterly using modified fyke nets from October 2003 to June 2005 in 18 interior tidal marsh channels spanning 3 distinct river systems: Petaluma River, Napa River and West Delta. We collected 116 samples and 9452 individuals of 30 fish species. Four non-native species dominated—Mississippi silverside, western mosquitofish, yellowfin goby, and rainwater killifish—with an additional 13 species occurring commonly (represented equally by natives and non-natives, residents and transients). Large seasonal differences in composition and abundance of fishes occurred, with the lowest abundances in winter and spring and highest abundances in summer and fall. Correlation of ordination scores and environmental variables further supported the importance of season, as well as fish species’ status (native vs. non-native), feeding preference (pelagic vs. demersal), and marsh utilization (resident vs. transient), as factors influencing fish assemblage composition. The proximity of the marsh systems to freshwater and marine influences, which largely control salinity and temperature variation, explained 26% of the variation in fish composition, while channel geomorphology explained 22%. We recommend that both edge habitat (which may be beneficial to fish foraging success) and the extent of tidal connectivity (which allows access for fishes), in addition to location along the estuarine gradient, be considered in designing and managing tidal marsh restoration.

English

&nbsp; To study the genetic and phylogenetic relationship of gobioid fishes in China, the representatives of 10 gobioid fishes from 2 subfamilies in China were examined by amplified fragment length polymorphism (AFLP) analysis. We established 220 AFLP bands for 45 individuals from the 10 species, and the percentage of polymorphic bands was 100%. The percentage of polymorphic loci within species ranged from 3.61 to 58.56%.&nbsp;Chaeturichthys stigmatias&nbsp;showed the greatest percentage of polymorphic loci (58.56%), the highest Nei&rsquo;s genetic diversity (0.2421 &plusmn; 0.2190) and Shannon&rsquo;s information index (0.3506 &plusmn; 0.3092), while&nbsp;Pterogobius zacalles&nbsp;showed the lowest percentage polymorphic loci (3.61%), the lowest Nei&rsquo;s genetic diversity (0.0150 &plusmn; 0.0778) and lowest Shannon&rsquo;s information index (0.0219 &plusmn; 0.1136). The topology of UPGMA tree showed that the individuals from the same species clustered together and the 10 species formed two major clades. One clade consisted&nbsp;Cryptocentrus filifer,&nbsp;P.&nbsp;zacalles,&nbsp;Tridentiger trigonocephalus,Chaeturichthys hexanema,&nbsp;C.&nbsp;stigmatias,&nbsp;Acanthogobius flavimanus&nbsp;andSynechogobius ommaturus,&nbsp;and the other clade consisted&nbsp;Odontamblyopus rubicundus,&nbsp;Trypauchen vagina&nbsp;and&nbsp;Ctenotrypauchen microcephalus. The results agreed with the traditional taxonomy of the morphological characters. AFLP fingerprints were successfully used to study the phylogenetic relationship of the gobioid fishes and it identified species origins of morphologically similar taxa. &nbsp; Key words:&nbsp;Phylogenetic, amplified fragment length polymorphism (AFLP), gobiidae, Amblyopinae, gobiinae.

Seasonal dynamics of fishes in tidepools on tidal mudflats in the Tama River estuary, central Honshu, Japan

We investigated seasonal dynamics of fish in tidepools on tidal mudflats in the Tama River estuary, Japan. A total of 1,156 individuals of 8 gobiid species were collected from May 2008 to April 2009. The total abundance of fishes peaked in September and October. Of three dominant species, Acanthogobius flavimanus was found only in spring and early summer, whereas Pseudogobius masago and Mugilogobius abei occurred in all seasons. The utilization patterns of tidepools with/without cobbles were different among the latter two species.

Molecular identification and transmission studies of X-cell parasites from Atlantic cod Gadus morhua (Gadiformes: Gadidae) and the northern black flounder Pseudopleuronectes obscurus (Pleuronectiformes: Pleuronectidae)

BackgroundEpidermal pseudotumours from Hippoglossoides dubius and Acanthogobius flavimanus in Japan and gill lesions in Limanda limanda from the UK have been shown to be caused by phylogenetically related protozoan parasites, known collectively as X-cells. However, the phylogenetic position of the X-cell group is not well supported within any of the existing protozoan phyla and they are currently thought to be members of the Alveolata.Ultrastructural features of X-cells in fish pseudotumours are somewhat limited and no typical environmental stages, such as spores or flagellated cells, have been observed. The life cycles for these parasites have not been demonstrated and it remains unknown how transmission to a new host occurs.In the present study, pseudobranchial pseudotumours from Atlantic cod, Gadus morhua, in Iceland and epidermal pseudotumours from the northern black flounder, Pseudopleuronectes obscurus, in Japan were used in experimental transmission studies to establish whether direct transmission of the parasite is achievable. In addition, X-cells from Atlantic cod were sequenced to confirm whether they are phylogenetically related to other X-cells and epidermal pseudotumours from the northern black flounder were analysed to establish whether the same parasite is responsible for infecting different flatfish species in Japan.ResultsPhylogenetic analyses of small subunit ribosomal DNA (SSU rDNA) sequence data from Atlantic cod X-cells show that they are a related parasite that occupies a basal position to the clade containing other X-cell parasites. The X-cell parasite causing epidermal pseudotumours in P. obscurus is the same parasite that causes pseudotumours in H. dubius. Direct, fish to fish, transmission of the X-cell parasites used in this study, via oral feeding or injection, was not achieved. Non-amoeboid X-cells are contained within discrete sac-like structures that are loosely attached to epidermal pseudotumours in flatfish; these X-cells are able to tolerate exposure to seawater.A sensitive nested PCR assay was developed for the sub clinical detection of both parasites and to assist in future life cycle studies. PCR revealed that the parasite in P. obscurus was detectable in non-pseudotumourous areas of fish that had pseudotumours present in other areas of the body.ConclusionsThe inability to successfully transmit both parasites in this study suggests that either host detachment combined with a period of independent development or an alternate host is required to complete the life cycle for X-cell parasites. Phylogenetic analyses of SSU rDNA confirm a monophyletic grouping for all sequenced X-cell parasites, but do not robustly support their placement within any established protist phylum. Analysis of SSU rDNA from X-cells in Japanese flatfish reveals that the same parasite can infect more than one species of fish.

Development of Eggs, Larvae and Juveniles of the Oriental Goby Acanthogobius flavimanus Reared in the Laboratory

Development of Eggs, Larvae and Juveniles of the Oriental Goby Acanthogobius flavimanus Reared in the Laboratory

Histological Changes in Some Vesceral Organs of the Oriental Goby, Acanthogobius flavimanus after Spawning Season, with Reference to Starvation

Histological Changes in Some Vesceral Organs of the Oriental Goby, Acanthogobius flavimanus after Spawning Season, with Reference to Starvation

Effects of Nonylphenol and 2,2', 4,6,6'-pentachlorobiphenyl on in vitro Sex Steroid Production in Maturing Oocytes of the Yellowfin Goby, Acanthogobius flavimanus

Several studies have reported that nonylphenol (NP) and 2,2', 4,6,6'-pentachlorobiphenyl (PCB104) exhibit estrogenic activity. To investigate the estrogenic potency of NP and PCB104 during oocyte maturation, fully vitellogenic oocytes (0.76 mm diameter in average) of yellow fin goby, Acanthogobius flavimanus, were exposed in vitro to these chemicals at different concentrations (0.1, 1, 10, 100, and 1,000 ng/mL) with the exogenous precursor <TEX>$17\alpha$</TEX>-hydroxyprogesterone (<TEX>$17{\alpha}OHP$</TEX>) 50 ng/mL in the presence or absence of human chorionic gonadotropin (HCG). The production of testosterone (T), estradiol-<TEX>$17\beta$</TEX> (E2), and <TEX>$17\alpha,20\beta$</TEX>-dihydroxy-4-pregnen-3-one (<TEX>$17\alpha20{\beta}OHP$</TEX>) in response to NP or PCB104 were measured by radioimmunoassay. Steroid levels were also expressed as E2/T and E2/<TEX>$17\alpha20{\beta}OHP$</TEX> ratios. In the absence of HCG, no significant differences in either NP or PCB104 treatment groups were observed. In the presence of HCG, NP treatment did not show significant differences in the production of T, E2, and <TEX>$17\alpha20{\beta}OHP$</TEX> at any concentrations tested, but E2/T ratios were decreased at concentrations of 0.1, 1, 10, and 1,000 ng/mL compared with the control group. PCB104 decreased E2 production at concentrations of 0.1, 10, and 1000 ng/mL, but did not show significant differences in the production of T and <TEX>$17\alpha20{\beta}OHP$</TEX> at any concentration tested. While E2/T ratios were decreased at PCB104 concentrations of 0.1, 1, 10, and 1,000 ng/mL, E2/<TEX>$17\alpha20{\beta}OHP$</TEX> ratios were also decreased at 0.1, 10, and 1,000 ng/mL compared with the control. Results indicate that both NP and PCB104 appeared to have antiestrogenic effects during this phase.

X-cells in pseudotumors of yellowfin goby Acanthogobius flavimanus: a protistan organism distinct from that in flathead flounder Hippoglossoides dubius

Yellowfin goby Acanthogobius flavimanus affected with X-cell pseudotumors were sampled from a river estuary in Tokyo Bay, Japan. We amplified the gene for small subunit ribosomal RNA (18S rRNA) of X-cells of the goby with PCR using universal primers. The gene that we obtained (DDBJ Accession no. AB451874) showed 91% sequence identity to that of the X-cells of the flathead flounder Hippoglossoides dubius. With in situ hybridization, the probes specific for the gene that we obtained hybridized with the goby X-cells but not with the flounder X-cells, whereas probes for the 18S rRNA gene of flounder X-cells hybridized with the flounder X-cells but not with goby X-cells. These findings indicate that, although the X-cells found in the goby are closely related to the protist found in flounder, the two are clearly distinct organisms.

Echinostoma hortense and Heterophyid Metacercariae Encysted in Yellowfin Goby, Acanthogobius flavimanus, from Shinan-gun and Muan-gun (Jeollanam-do), Korea

Fishborne trematode (FBT) metacercariae were investigated in yellowfin goby, Acanthogobius flavimanus, collected from Shinan-gun and Muan-gun, Jeollanam-do (province), Korea. All collected fishes were examined using the artificial digestion method. In all of 15 gobies from Aphae-myeon in Shinan-gun, metacercariae of Stictodora spp. (334 metacercariae/fish), Heterophyes nocens (153/fish), and Heterophyopsis continua (20/fish) were detected. In 2 of 14 gobies from Jido-myeon in Shinan-gun, 8 Echinostoma hortense metacercariae in total were detected. In 15 gobies from Haeje-myeon in Muan-gun, the metacercariae of H. continua were found in 100%, Stictodora spp. in 86.7%, and H. nocens in 6.7% of fish examined. The average numbers of metacercariae per infected fish were 23.3 (H. continua), 416.0 (Stictodora spp.), and 2.0 (H. nocens), respectively. The metacercariae of E. hortense found in gobies were elliptical, with 150 x 138 microm in average size, and had 27 collar spines on the head crown. The above results suggest that yellowfin gobies from 2 localities may be the potential infection sources of FBT. Moreover, it is proved for the first time that the yellowfin goby, A. flavimanus, acts as a second intermediate host for E. hortense.

Diet and growth of non-native Mississippi silversides and yellowfin gobies in restored and natural wetlands in the San Francisco Estuary

We examined how wetland restoration status influenced habitat quality for fishes by comparing otolith-calculated growth rates and diets of 2 abundant non-native fish species, the locally transient planktivorous Mississippi silverside Menidia audens and the resident demersal-feeding yel- lowfin goby Acanthogobius flavimanus, in 2 wetlands undergoing restoration ('restoring' wetlands) and 1 natural wetland (Napa River, San Francisco Estuary, California, USA; 38° 10' N; 122° 18' W). Native species with similar trophic requirements were too few in abundance to serve as study organ- isms. Differences in fish diet and growth based on restoration status were expected for the more res- ident goby species, but not for the transient silversides. Fish were collected in June 2004 and 2005 from a 10 yr old restoring marsh, a 50 yr old restoring marsh and a natural marsh, using a modified fyke net. Diet of silversides was primarily composed of copepods, cumaceans, and flying insects, while yellowfin goby diets were composed of annelids, cumaceans, and amphipods. Prey species bio- mass in the stomachs of yellowfin gobies was significantly different between marshes, but these dif- ferences were not dependent on restoration status. No significant differences in Mississippi silverside growth rates were detected, and yellowfin goby growth rates varied somewhat between marshes and years, but were not significantly different between restored versus reference sites. Based on these findings, we suggest that adequate prey abundance and prey species composition is available for these fish species in both our restored and natural study sites. It also appears that some restoring breached wetlands can quickly (within 10 yr) provide equivalent habitat to natural areas, at least for generalist, non-native fishes; however, consideration of underlying mechanisms of restoration will be important in designing wetlands that specifically favor native fish populations.

Molecular Cloning of Two Estrogen Receptors Expressed in the Testis of the Japanese Common Goby, Acanthogobius flavimanus

We isolated cDNA clones of two estrogen receptors (ER1 and ER2) from testis of the Japanese common goby (Acanthogobius flavimanus). The cDNAs of ER1 contained 3,796 nucleotides, including an open reading frame encoding 564 amino acids (Mr: 61.9 kDa); the cDNA for ER2 was 3,274 nucleotides long, with an open reading frame of 567 amino acids (Mr: 63.5 kDa). The deduced aminoacid sequences of ER1 and ER2 each had a characteristic ER structure consisting of five domains (A/B, DNA-binding, D, ligand-binding, and F) and were homologous to ERalpha and ERbeta of other vertebrates. We therefore named ER1 and ER2 as goby ERalpha (gERalpha) and goby ERbeta (gERbeta), respectively. The DNA- and ligand-binding domains in each gER showed high similarity to the corresponding domains of other vertebrates. Analysis of the distribution of gERalpha and gERbeta mRNAs in tissue by reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed that gERalpha was expressed at high levels in brain and testis, and gERbeta was expressed most strongly in testis. In situ hybridization showed that the mRNA of each gER was expressed mainly in the Sertoli cells of goby testis.

Introduced Yellowfin Goby, Acanthogobius flavimanus: Diet and Habitat Use in the Lower Mokelumne River, California

The introduced yellowfin goby (YFG) is now common throughout the tidal portion of the Sacramento-San Joaquin River system. We investigated its habitat use, size and diet in the Mokelumne River, an eastern tributary to the system. Catch per unit effort (CPUE) by boat electrofishing was significantly higher in the fall than all other seasons sampled over four years. Habitat type, turbidity and dissolved oxygen were not significantly related to CPUE between years and seasons. Temperatures were negatively related to CPUE in fall sampling only. Delta outflow and CPUE showed a significant negative relationship. Fish captured ranged from 27 mm SL (standard length) (33 mm TL (total length)) to 155 mm SL (196 mm TL) (mean 113 mm SL (138 mm TL)), with largest fish captured during the fall. Seasonal and annual analysis showed a diet composed of a variety of macroinvertebrates, including chironomids, gammarids, aquatic isopods and ephemeropterans with no difference in composition among seasons or years. The YFG’s generalist diet gives it an advantage as a successful invader, but salinity requirements appear to limit its expansion potential.

Relationships between short-term variations in density of juvenile yellowfin goby Acanthogobius flavimanus and environmental variables on an estuarine mudflat

Weekly variations in density of juvenile yellowfin goby Acanthogobius flavimanus with a variety of environmental variables (e.g. water temperature, salinity and transparency, and prey density) were investigated on a tidal mudflat within the Tama River estuary, central Japan, from March to July 2001. Metamorphosing newly settled juveniles occurred from mid-March to late May. Metamorphosed benthich juveniles first appeared in late March, the density sharply increasing to a peak (67.0 ind./m2) in early May but rapidly decreasing to less than 10% of that two weeks later. No consistent relationships were apparent between short-term variations in fish density by developmental stages and water temperature, or salinity. In contrast, a weak negative relation was found between juvenile density and water transparency. Further, benthic juvenile density was positively related to short-term fluctuations of errant polychaetes, which is one of the main prey items.

A survey of Heterophyes nocens and Pygidiopsis summa metacercariae in mullets and gobies along the coastal areas of the Republic of Korea

The infection status of mullets Mugil cephalus (n = 139) and gobies (n = 35) Acanthogobius flavimanus with metacercariae of Heterophyes nocens and Pygidiopsis summa was examined in 11 western, southern, and eastern coastal areas of the Republic of Korea, using a digestion technique. Heterophyid metacercariae were highly prevalent in mullets from western and southern coastal areas; Shinan-gun (100% for H. nocens and 100% for P. summa), Muan-gun (93% and 100%), Buan-gun (42% and 75%), Seocheon-gun (73% and 53%), Ganghwa-gun (47% and 100%), Sacheon-shi (47% and 77%), and Gangjin-gun (50% and 70%, respectively). Only 1 (10%) of 10 mullets from an eastern coastal area, i.e., Donghae-shi, was positive for P. summa metacercariae. Metacercarial densities were the highest in the trunk of mullets for H. nocens and the gill for P. summa. Gobies from Muan-gun were positive for H. nocens (40%) and P. summa metacercariae (40%), and gobies from Seocheon-gun revealed H. nocens metacercariae (20%). The metacercarial density was remarkably higher in mullets than in gobies. The results revealed that H. nocens and P. summa metacercariae are prevalent in mullets and gobies from coastal areas of the Republic of Korea, and the prevalence and intensity of infection vary according to geographical locality.