Pennahia Argentata Research Articles

Analysis of genetic structure of white croaker using amplified fragment length polymorphism (AFLP) markers

The genetic structure of 4 populations of white croaker Pennahia argentata was analyzed by amplified fragment length polymorphism (AFLP) technology. A total of 304 putative loci were detected by the 5 primer combinations, of which 200 were polymorphic. The proportion of polymorphic loci among four populations varied from 47.13 to 57.63%. The population with the highest Nei’s genetic diversity and Shannon diversity index was Ariake Sea population, the lowest Nei’s genetic diversity and Shannon diversity index was found in Ise Bay population. Two geographic clades (Chinese clade and Japanese clade) were detected among 70 individuals of white croaker by AFLP markers; molecular variance analysis and pairwise FST also supported the separation of Chinese and Japanese populations ofP. argentata. The Pleistocene isolation and biological characteristics of species may be responsible for the genetic differentiation of P. argentata between China and Japan coastal waters. Our result also revealed that white croaker might choose the retention larval strategy within coastal waters to minimize the offshore dispersal. Key words: White croaker, Pennahia argentata, amplified fragment length polymorphism (AFLP), genetic structure.

Philometra sawara sp. n. and a redescription of Philometra sciaenae Yamaguti, 1941 and Philometra nemipteri Luo, 2001 (Nematoda: Philometridae): a morphological and molecular approach

Morphological data and molecular analyses are used to describe the taxonomy of philometrid nematodes of the genus Philometra Costa, 1845, found in the gonads of marine fishes in Japan. A new Philomnetra species, P. sawara sp. n., is described based on male and female specimens collected from the gonads of Scomberomorus niphonius (Cuvier) (Japanese Spanish mackerel). Two additional species, Philometra nemipteri Luo, 2001 and Philometra sciaenae Yamaguti, 1941, are confirmed as valid species and are redescribed based on specimens collected from the gonads of Nemipterus virgatus (Houttuyn) (golden threadfin bream) and Pennahia argentata (Houttuyn) (silver croaker), respectively. Male P. nemipteri are first reported and described in this study. Redescriptions of female P. nemipteri and male and female P. sciaenae were also necessary based on our morphological observations. A molecular comparison of the internal transcribed spacer 2 (ITS2) region of the ribosomal DNA between P. sawara, P. nemipteri, P. sciaenae, and previously reported philometrid nematodes from the genus Philometra and Philometroides Yamaguti, 1935 supports the conclusion that the three Philometra species in the current study are independent. An ITS2-derived neighbour-joining tree, consisting of both the current specimens and previously described Philometra and Philometroides species, is also presented.

Genetic identification of fish eggs collected in Sendai Bay and off Johban, Japan

Mitochondrial DNA typing of 52 fish eggs collected in Sendai Bay and off Johban revealed ten haplotypes of the 225–251 bp region of 16S ribosomal DNA. Comparing with known sequences of fishes, we identified them as Trachurus japonicus (Carangidae), Pagrus major, Evynnis japonica (Sparidae), Paralichthys olivaceus, Pseudorhombus sp. (Paralichthidae), Pennahia argentata (Sciaenidae) and Platycephalus sp. (Platycephalidae). The occurrence of Trachurus japonicus and sparid eggs in the study area indicates significant extensions to the ranges of their spawning sites northward. Our method is useful for identifying fish eggs that are difficult to diagnose by morphology, and to uncover cryptic fish egg assemblages in the field.

망지를 이용한 트롤 탈출장치 개발

Sea experiment for this study was carried out to develop a Trawl Escapement Net(TEN) using net material to improve the survival rate of undersized fishes that escaped from trawls in the Korean southern sea in May and November, 2005. Three kinds of Trawl Escapement Net(TEN) were examined to increase the escapement rate for fishes escaped from the TEN, and total catches in the codend and cover-net were investigated. The main catch species in the experimental fishing trials using a V shape TEN(A type) in May were Korean pomfret(Pampus echinogaster), slimy(Leiognathus nuchalis), gizzard shad(Konosirus punctatus), white croaker(Pennahia argentata) and smelt(Sillago sihama). In the experimental fishing trials using a V shape TEN with a protector for undersized fishes(B type) and a panel shape TEN with a protector(C type) in November, the main catch species were horse mackerel(Trachurus japonicus), sea pike (Sphyraena japonica), large-head hairtail(Trichiurus lepturus), kammal thryssa(Thryssa kammalensis), white croaker(Pennahia argentata), butterfish(Psenopsis anomala) and red gurnard(Lepidotrigla microptera). Most of large-sized fish species like Korean pomfret and Spanish mackerel could not escape through the TEN in the B type and C type. Catches of horse mackerel were highest in the experimental fishing of November and escapement rates for most fish species including horse mackerel were higher in the C type compared with B type.

Genetic variation among white croaker populations

To investigate the genetic structures and differentiation of different wild populations of white croaker (Pennahia argentata), horizontal starch gel electrophoresis was performed on 133 individuals collected from five different locations in China and Japan. The eleven enzyme systems revealed 15 loci, of which eleven were polymorphic. The percentage of polymorphic loci of white croaker populations varied from 6.67% to 53.33%; the mean observed and expected heterozygosity ranged from 0.0033 to 0.0133 and 0.0032 to 0.0191, respectively. The expected heterozygosity revealed a low genetic variability for white croaker in comparison with other marine fishes. The genetic distances between populations ranged from 0.00005 to 0.00026. A weak differentiation was observed within each clade and between clades; and no significant differences in gene frequencies among populations were observed in white croaker. Among the five populations, three Chinese populations showed more genetic diversity than that in Japanese populations.

Three species of parasites emerging on the gills of mulloway, Argyrosomus japonicus (Temminck and Schlegel, 1843), cultured in Australia

Mulloway is an Indo‐West Pacific sciaenid fish with a short history of commercial culture in Australia. In January 2005, a harvest sample of these fish cultured off South Australia was observed macroscopically with large numbers of a blood‐feeding polyopisthocotylean. Epizootics of this parasite may pose a threat to the economics of farming this species, since it appears to be associated with anemia, as indicated by pale gills. Based on morphological characters, we identify the monogenean as Sciaenacotyle sciaenicola [Murray, F.V., 1932. Correction: note on a microcotylid from Sciaena antarctica. Parasitology 24, 448.] Mamaev [Mamaev, Yu.L., 1989. On species composition and morphological features of the Microcotyle genus (Microcotylidae, Monogenoidea). In: Lebedev, B.I. (Ed.), Investigations in Parasitology . Collection of Papers. DBNTs AN SSSR: Vladivostok, pp. 32–38 [In Russian].]. Maximum likelihood analysis of ITS2 rDNA confirms that the genus Sciaenacotyle is not closely related to two other microcotylid genera also known from sciaenid fishes: Diplostamenides (represented by D. sciaenae (Goto, 1894) Mamaev [Mamaev, Yu.L., 1989. On species composition and morphological features of the Microcotyle genus (Microcotylidae, Monogenoidea). In: Lebedev, B.I. (Ed.), Investigations in Parasitology . Collection of Papers. DBNTs AN SSSR: Vladivostok, pp. 32–38 [In Russian].] from white croaker, Pennahia argentata, in Japan) and Anchoromicrocotyle (represented by A. guaymensis [Bravo‐Hollis, M., 1981. Helminths of fish of the Mexican Pacific. XXXVI. A new genus and subfamily of the family Microcotylidae Taschenberg, 1879 emended. An. Inst. Cienc. Mar Limnol. Univ. Nac. Auton. Mex. 8, 305–313.] from white seabass, Atractoscion nobilis, in California). In more intensive sampling of gills, we detected two other species of metazoan parasites, the monopisthocotylean Calceostoma glandulosum Johnston et Tiegs, 1922; and a copepod we identify as Caligus cf. elongatus, a sea louse very similar to C. elongatus Nordmann (1832), which affects farmed salmonids in the North Atlantic. Praziquantel bath treatment at an initial concentration that removed S. sciaenicola from mulloway gills did not remove C. glandulosum.

Reproductive cycle, sexual maturity and diel-reproductive periodicity of white croaker, Pennahia argentata (Sciaenidae), in Ariake Sound, Japan

The white croaker, Pennahia argentata (Houttuyn), is abundant in demersal fish assemblages in Ariake Sound and is a commercially important species. The reproductive biology of white croaker was studied by measurement of gonadosomatic indices (GSI) and histological examination of ovaries. Ovaries were classified into one of five maturity stages based on histological data: (1) immature/resting stage; (2) developing stage; (3) maturing stage; (4) ripe/spawning stage; (5) spent stage. The spawning season lasts from April to September but most activity is observed from May to August. Age at sexual maturity was assumed to be 1 year. Postovulatory follicles coexisted with yolk stage oocytes in histological sections of ovaries indicating that white croaker is a multiple spawner, spawning more than once in a single spawning season. Judging from the diel changes in the proportion of females with ovaries containing postovulatory follicles and oocytes at maturation stage, most females spawned in the evening between 19:00 and 21:30 h.

Geographic variation in the growth of white croaker, Pennahia argentata, off the coast of northwest Kyushu, Japan

We examined geographic variation in the growth of white croaker,Pennahia argentata, off the coast of northwest Kyushu, Japan, Ariake Sound, Tachibana Bay, Omura Bay and the Goto Sea by examination of otoliths. The outer margins of the otoliths showed that a opaque zone was formed once a year, with its peak in June, and could be used as an annulus. White croaker caught during this study reached a maximum age of 10 years in the Goto Sea. The growth curves for both sexes in all localities were expressed by the von Bertalanffy growth equations from back-calculated total length of fish. We found significant sexual differences in growth curves in Ariake Sound, Tachibana Bay and the Goto Sea. For both sexes, white croaker in the Goto Sea reached the largest length at each estimated age of the four localities. The growth curves for both sexes showed significant differences among four localities, suggesting that several stocks may exist in the study area although the greatest distance between each locality was at most 30 km.

CDNA cloning of myosin heavy chain from white croaker fast skeletal muscle and characterization of its complete primary structure

SUMMARY: A cDNA library constructed from the dorsal fast skeletal muscle of white croaker Pennahia argentata was screened for myosin heavy chain using antibody raised against carp fast skeletal myosin. A full-length cDNA was further cloned by reverse transcription–PCR and 5′-RACE using first-strand cDNA as a template together with appropriate sets of primers. The entire cDNA consisted of 5986 nucleotides (nt) with 64 nt 5′-untranslated and 129 nt 3′-untranslated regions. This full-length cDNA had an open reading frame encoding a polypeptide of 1930 amino acid residues. Amino acid alignment with myosins from various vertebrates revealed some striking differences between fish and mammalian sequences which could be due to their position in the vertebrate evolutionary process. Hydrophilicity analysis revealed two different features of the myosin molecule: S1 heavy chain showed a mixed profile of hydrophobicity and hydrophilicity, whereas rod had a profile of only hydrophilicity. Comparison of amino acid sequences in the rod region between white croaker and walleye pollack showed a markedly high identity of 92%. White croaker myosin rod had a characteristic seven-residue (heptad) repeat (a, b, c, d, e, f, g)n, where positions a and d were normally occupied by hydrophobic residues, and positions b, c and f by oppositely charged residues, which may lead to interhelical electrostatic attractions stabilizing the coiled-coil of α-helices.

CDNA cloning of fast skeletal myosin heavy chain of white croaker fish Pennahia argentata

cDNA cloning of fast skeletal myosin heavy chain of white croaker fish Pennahia argentata

Interspecific genetic divergence in sciaenids from Japan and its adjacent waters

Genetic divergence and phylogenetic relationships amongNibea mitsukurii, Nibea albiflora, Pennahia argentata, Argyrosomus japonicus, Atrobucca nibe andLarimichthys crocea were investigated by examining the electrophoretic patterns of 14 enzymes. The allele frequencies of 21 loci were estimated to calculate the genetic distances (D). The averageD value among the sciaenid species increased in proportion to the level of taxonomic category. Relationships estimated by genetic markers well accorded with those estimated by morphological characters. The 6 sciaenid species were clearly divided into two distinct groups at aD value of 1.41.