Lutjanus Argentimaculatus Research Articles

The effects of varying dietary protein level on growth, feed conversion, body composition and apparent digestibility coefficient of juvenile mangrove red snapper,Lutjanus argentimaculatus(Forsskal 1775)

The effects of several dietary protein levels on the growth, feed conversion, body composition and diet digestibility of juvenile Lutjanus argentimaculatus (body weight 12.3 g) were examined. Seven isolipidic (7.4%) diets were formulated to contain graded levels of protein (28–58%) with dietary energy ranging from 19.7 to 21.5 kJ g−1. Diets were distributed to triplicate groups of fish thrice a day at ration of 2% body weight for 90 days. Growth, feed conversion, protein utilization and digestibility of nutrients increased with increasing dietary protein level up to 43%, after which no significant improvement was observed. Digestibility of dry matter and energy showed a concomitant increase with the reduction in dietary wheat meal, attaining maximal values with high protein diets. No significant differences were detected in moisture, protein, lipid and ash content of whole fish or body organs as dietary protein increased. The mesenteric fat, hepato- and viscerosomatic indices decreased with increasing protein level. The cholesterol, triglycerides and haematocrit values were similar among treatments, except that high levels of plasma lipids were recorded above 43% protein diet. The use of a practical diet containing 43% protein is appropriate for the growth of L. argentimaculatus juveniles under the experimental conditions of the present study.

Identification of putative cathepsin S in mangrove red snapper Lutjanus argentimaculatus and its role in antigen presentation

Cathepsin S (CTSS) is a key enzyme employed in the histocompatibility complex (MHC) class II-restricted antigens, which are presented by processing class II-associated invariant chains and loaded antigen peptides into class II molecules. To date, little is known about the character and function of CTSS in fish. In the present study, we screened and identified a CTSS cDNA sequence from the mangrove red snapper head kidney cDNA library. The full-length CTSS cDNA contained 1339-bp nucleotide acids encoding 337 amino acids. The sequence shared high identity and similarity with other known cathepsins, especially CTSS (about 56–78% and 79–89%, respectively). Like other cathepsins, the deduced peptide consisted of regions with N-terminal signal peptides, propeptides, and mature peptides. A typical ERWNIN motif in L-like cathepsins and three conservative catalytic activity sites forming a catalytic triad active center were respectively identified in the pro-peptide and mature peptide regions of CTSS. Phylogenetic analysis revealed that mangrove red snapper CTSS was located in the CTSS clade belonging to the L-like cathepsin group, and evolved from the same ancestry. To further characterize the biological activity of the putative CTSS of mangrove snapper, CTSS was expressed in Escherichia coli M15 strains. Like other mammalian CTSS, the recombinant CTSS (rCTSS) had autocatalytic activation properties, can remove pro-peptides, and can release active mature peptides. Active CTSS had the ability to catalyze Z-Phe-Arg-AMC substrates in acidic conditions (pH 5.0) and weak alkaline environments (pH 7.5); this activity could be blocked by the cysteine protease inhibitor E-64. Active CTSS can process recombinant Ii chains (invariant chains) in a stepwise manner in vitro. The results indicate that mangrove red snapper CTSS is a lysosomal cysteine protease family member with a key role in antigen processing in fish.

Migration patterns of juvenile Lutjanus argentimaculatus in a mangrove estuary in Trang province, Thailand, as revealed by ultrasonic telemetry

Migrational patterns of mangrove jack Lutjanus argentimaculatus were studied in a mangrove estuary in Trang province, Thailand, using ultrasonic telemetry. Ultrasonic coded transmitters were surgically implanted in 18 fish and 16 of them were subsequently monitored by nine fixed receivers installed along Sikao Creek estuary in June and November 2006. Due to technical limitations all of the individuals were released in the middle of the creek. Their movements were monitored for a period of up to 1 month, the data being used to describe short term migration of juvenile Lutjanus argentimaculatus in the creek and to find possible environmental cues for the observed movements. All of the individuals showed a tide related movement pattern, suggesting foraging in the small mangrove channels and/or mangrove forest during high tides. 50% of the fish left the study area for the open coast area within a short time following release, indicating that a part of juvenile L. argentimaculatus may move in between estuarine habitats instead of being site attached. As the fish were reared in fish cages for a certain period of time before the study this behavior could partly be explained by the time spent in captivity. It was found that L. argentimaculatus showed higher movement activity during night high tides possibly explained by an increased availability of the sough after food items.

Intestinal microbiota of mangrove red snapper (Lutjanus argentimaculatus Forsskål, 1775) reared in sea cages

Using polymerase chain reaction ampli¢cation of 16S rDNA coupled to denaturing gradient gel electrophoresis (DGGE) and sequencing of isolated amplicons, we investigated the microbiota of the intestinal digesta and mucosal surface in mangrove red snapper cultured in a cage aquaculture area in Daya Bay. A total of 14 sequences were characterized by phylogenetic analysis. Among the bacterial species determinated from sequences, the g-Proteobacteria group (64.25%, nine species) dominated absolutely in ¢sh intestines. Others belonged to Spirochaetes (14.3%, two species), Cyanobacteria (14.3%, two species) and Firmicutes (7.15%, one species). However, the bacteria were identi¢ed as uncultured accounting for 28.6% (four species). The apparent bacterial richness (calculated as the numbers of DGGE bands) was signi¢cantly higher in digesta than that in mucosal tissue samples (Po0.05). There existed ¢ve dominant individual populations including one unknown species of Firmicutes, Arthrospira sp.,Vibrio metschnikovii,Vibrio harveyi andVibrio sp. in intestinal digesta, and in contrast, only three dominant individual populations including Vibrio natriegens, V. harveyi and Vibrio sp. in intestinal mucosal surface. The results indicated that the microbiota in intestinal digesta was signi¢cantly diierent from that in mucosal surface.

Growth and Feed Efficiency in Mangrove Red Snapper, (Lutjanus argentimaculatus Forsskal 1775) Fed Practical Diets Supplemented with L-ascorbyl-2-monophosphate-Mg

Growth and feed efficiency were determined in red snapper, Lutjanus argentimaculatus (Forsskal 1775), fed diets containing L-ascorbyl-2-monophosphate-Mg (AMP). Fish (13.39±0.08 g) were fed a practical diet without vitamin C supplement for four weeks then stocked in twelve 650-l tanks at 30 fish/tank and fed one of four practical diets containing AMP at 0, 60, 180, or 540 mg/kg dry diet for 17 weeks. Survival rates in all treatments were similar (88.9-98.9%). Fish fed the 0 or 540 ppm diets had inferior final average weights, protein efficiency ratios, and feed conversion ratios than fish fed the 60 or 80 ppm diets (p<0.05). Growth of fish fed the 0 or 540 ppm diets slowed down on day 60 and fish fed the AMP-free diet exhibited clinical signs of vitamin C deficiency with a soft body and a significantly high (p<0.05) hepatosomatic index. Ascorbic acid in brain and liver tissues rose with the level of dietary AMP. Fish fed the 540 ppm diet had significantly lower hematocrit (p<0.05) than fish fed the 60 or 180 ppm diets. Histological analysis of the liver and kidney of fish fed the 180 and 540 ppm diets showed changes indicative of possible toxic effects. Based on growth, feed efficiency, tissue histology, and hematocrit level, AMP at 540 ppm is toxic to snapper. Thus, supplementation of 60 ppm AMP or its equivalent 26 ppm ascorbic acid in practical diets for red snapper promotes optimum growth and feed efficiency and prevents vitamin C deficiency symptoms.

Pathological manifestations of the acanthocephalan parasite, Tenuiproboscis sp. in the mangrove red snapper ( Lutjanus argentimaculatus) (Forsskål, 1775), a candidate species for aquaculture from Southern India

The study describes the pathological manifestations of the acanthocephalan, Tenuiproboscis sp . in the mangrove red snapper, Lutjanus argentimaculatus, a highly valued food fish along the southwest coast of India. The fish collected from Calicut, Cochin and Kannur harboured the acanthocephalan parasite, Tenuiproboscis sp. with up to 100% prevalence. Heavy infections with the parasites were observed in the posterior region of the intestine, almost blocking the lumen. At the site of parasite attachment, the surface of the intestine appeared thickened and the mucosal epithelium showed compression and abrasion. Intestinal folds were eroded along with thickening of lamina propria. The presoma of the parasites pierced the mucosal epithelium, lamina propria, muscle layers and serosa, reaching the peritoneal cavity, surrounded by a tunnel with collagenous fibers and granulocytes. Inflammation, granular tissue formation, connective tissue proliferation and associated host immune reactions were evident. Though the worms substantially damaged the architecture of the intestinal tissues, no apparent ill effects on the general health/condition of the fish were observed. The parasite was also recovered from Epinephelus malabaricus and Lates calcarifer. This is the first report of Tenuiproboscis sp. from L. argentimaculatus, E. malabaricus and L. calcarifer.

Age and growth during immature stages of the mangrove red snapper Lutjanus argentimaculatus in waters around Ishigaki Island, southern Japan

Age and growth during immature stages of the mangrove red snapper Lutjanus argentimaculatus were examined using 129 sectioned otoliths of fish collected in rivers and coastal areas around Ishigaki Island. Monthly changes in the marginal growth index indicated that ring marks (inner edge of opaque zone) are formed once a year around May. Estimated ages of the sampled fish ranged from 0.2 to 4.5 years. The proportion of mangrove red snappers collected in each sampling set in the rivers was associated with age, namely, the older the fish, the smaller the proportion. This result suggests that the mangrove red snapper gradually moves from the river habitat to coastal areas with increasing age between 1 and 3 years. The relationship between standard length (Y; cm) and age (X; year) was expressed by the linear regression Y = 6.30X + 5.41. Both the somatic and otolith growth of age-one and age-two fish collected in coastal areas were faster than those of fish collected in rivers, suggesting that individuals with fast growth leave the rivers earlier than those with slow growth. Whereas the basic growth pattern obtained in this study is similar to that of the mangrove red snapper in waters around Great Barrier Reef, Australia, there is a clear difference in length of time spent in rivers between the two populations, probably associated with the difference in the scale of the rivers used as nursery grounds.

Development of Mixed-feeding Stage Larvae of Red Snapper, Lutjanus argentimaculatus

Development of Mixed-feeding Stage Larvae of Red Snapper, Lutjanus argentimaculatus

Misleading the masses: detection of mislabelled and substituted frozen fish products in South Africa

Abstract von der Heyden, S., Barendse, J., Seebregts, A. J., and Matthee, C. A. 2010. Misleading the masses: detection of mislabelled and substituted frozen fish products in South Africa. – ICES Journal of Marine Science, 67: 176–185. Mislabelling poses a threat to the sustainability of seafood supply chains and, when frequent, can significantly affect conservation efforts. Here we identify the most popular fish in the South African market through consumer and retailer surveys and data gathered by a sustainable seafood campaign. Of these species, we tested a number of widely available and generally high-market priced fish, utilizing mtDNA 16S rRNA sequencing. Tests of 178 samples revealed that about half of all fillets are mislabelled. Most problematic was kob, Argyrosomus spp., for which some 84% of fillets provided belonged to other species, including mackerel, croaker, and warehou. Phylogenetic analyses provided strong support that the fillets sold as barracuda and wahoo were probably king mackerel and that red snapper fillets included fillets of river snapper, Lutjanus argentimaculatus, which is a species prohibited for sale in South Africa. We also discovered substitution of yellowtail for dorado. From preliminary population genetic comparisons, some 30% of kingklip samples probably had their origin in New Zealand, rather than southern Africa. The research revealed a market conducive to mislabelling through poor consumer and retailer awareness, and highlighted the value of sustainable seafood campaigns to draw attention to this.

Ciguatera incidence and fish toxicity in Okinawa, Japan

Okinawa being located in the subtropical region has the highest incidence of ciguatera in Japan. Officially, 33 outbreaks involving 103 patients have been reported between 1997 and 2006. The implicated species were Variola louti, Lutjanus bohar, Lutjanus monostigma, Epinephelus fuscoguttatus, unidentified Lutjanus sp., Plectropomus areolatus, Oplegnathus punctatus, Epinephelus polyphekadion, Caranx ignobilis and moray eel. Toxicities of the leftover meals, as determined by mouse bioassays, ranged from 0.025 to 0.8 MU/g or above (equivalent to 0.175–5.6 ng CTX1B/g). We collected 612 specimens of fish belonging to L. monostigma, L. bohar, Lutjanus argentimaculatus, Lutjanus russellii, V. louti, Variola albimarginata, and E. fuscoguttatus from the coasts around Okinawa and examined the toxicity of the flesh by the mouse bioassay. The rate of toxic fish was as follows: L. monostigma: 32.3%, L. bohar: 11.9%, V. louti: 14.3%, E. fuscoguttatus: 20.8%. Only one out of 36 samples of V. albimarginata and two of 74 samples of L. russellii were found toxic. None of the 35 samples of L. argentimaculatus was toxic. Nor the L. bohar samples weighing less than 4 kg were toxic. In all toxic samples, CTX1B was detected by LC/MS analysis but CTX3C and 51-hydroxyCTX3C were not.

Lipid oxidation and organoleptic response during shelf storage of some smoked marine fish in Kenya.

Peroxide Value (PV), Thiobarbituric Acid Reactive substances (TBARS), organoleptic properties and shelf life of some smoked marine fish namely Gerres oyena (“Chaa”), Lutjanus argentimaculatus (Red snapper) and Valamugil seheli (Mullet) were studied during storage. Both PV and TBARS for all the fish increased to a peak with storage time then decreased. PV in G. oyena was 10.80±1.07 mEq/kg on day 1 of storage, increased to 18.17±0.39 mEq/kg in day 8, peaked at 21.48±0.44 mEq/kg in day 11 then decreased to 8.50±2.34 mEq/kg on day 28. TBARS increased from 0.39±0.09 mg malondialdehyde/kg when fresh to 0.59±0.09 mg malondialdehyde/kg in day 8 then decreased to 0.07±0.004 mg malondialdehyde/kg on the 19th day of storage. PV in L. argentimaculatus was 61.65±0.09 mEq/kg on the 4th day of storage, increased to 112.86±0.19 mEq/kg on day 6 then decreased to15.17±0.54 mEq/kg on day 11. TBARS in L. argentimaculatus was 0.93±0.36 mg malondialdehyde/kg when fresh, 0.16±0.01 mg malondialdehyde/kg on day 1, 1.87±0.03 mg malondialdehyde/kg on day 8 and 0.06±0.01 mg malondialdehyde/kg on day 23. In Valamugil seheli, the PV was 57.59±0.11 mEq/kg on day 1 of storage, 76.55±0.49 mEq/kg on the 8th day, then it decreased to undetectable levels on the 28th day. The TBARS for fresh fish was 0.83±0.10 mg malondialdehyde/kg. After smoking it was 3.96±0.12 mg malondialdehyde/kg on day 4, 3.74±0.03 mg malondialdehyde/kg on day 8 then0.12± mg malondialdehyde /kg after 19 days of storage. The shelflives of the three fish species were monitored organoleptically during a 15 day storage period on day 1, 5 and 15 with any score of 5 or below out of 9 being the limit for rejection. The fish were stored on laboratory benches in the open at ambient temperatures of 30 0C and humidity of 60%. Organoleptic tests based on various attributes were done to establish consumer preference for the fish. The freshness score for G. oyena was 6.38, V. seheli 7.2 and L. argentimaculatus 7.5 at the end of 15 days storage. There was a significantly better score (p L.argentimaculatus compared to G. oyena and V. seheli. The overall mean score for all the organoleptic attributes for the 3 fish combined was 6.22. The most preferred attribute was taste with a score of 6.5. The most preferred fish was Lutjanus argentimaculatus followed by Gerres oyen a then Valamugil seheli .

Cryopreservation of red snapper ( Lutjanus argentimaculatus) sperm: Effect of cryoprotectants and cooling rates on sperm motility, sperm viability, and fertilization capacity

Sperm cryopreservation of red snapper ( Lutjanus argentimaculatus) is essentially unexplored, although many species of the Lutjanidae family are considered to be high-value commercial species. The objective of this study was to develop a species-specific cryopreservation protocol for red snapper ( L. argentimaculatus) sperm by optimizing cryoprotectants and cooling rates in the cryopreservation procedure. Ten cryoprotectants at four concentrations and two freezing protocols were examined in two separate experiments. In the first experiment, toxicity studies of dimethyl sulfoxide (DMSO), glycerol, propylene glycol (PG), ethylene glycol (EG), formamide, methanol, ethanol, sucrose, trehalose, and dimethylacetamide (DMA) on sperm motility were performed. Semen diluted 1:1 in Ringer solution were exposed to cryoprotectants at four final concentrations of 5%, 10%, 15%, or 20% for periods of 10, 20, 30, 40, 50, 60, 90, and 120 min at room temperature (25 °C). The cryoprotectants and concentrations that showed the least toxic effect on sperm motility were selected for cryopreservation trials. In the second experiment, selected cryoprotectants were then assessed for freezing capacity of sperm as follows: DMSO 5% and 10%, PG 5% and 10%, EG 5% and 10%, ethanol 5%, and methanol 5%. Semen was diluted 1:1 in Ringer solution and equilibrated with selected cryoprotectants for 10 min at room temperature. Sperm were frozen in a controlled-rate programmable freezer at four cooling rates of 3, 5, 10, and 12 °C/min from an initial temperature of 25 °C to final temperatures of −40 or −80 °C before plunging into liquid nitrogen. Sperm equilibrated in 10% DMSO and cooled at a rate of 10 °C/min to a final temperature of −80 °C had the highest motility (91.1 ± 2.2%) and viability (92.7 ± 2.3%) after thawing. The fertilization rate of frozen-thawed sperm (72.4 ± 2.4%) was not different (P > 0.05) from that of fresh sperm (75.5 ± 2.4%). This study apparently represents the first reported attempt for cryopreservation of L. argentimaculatus sperm.

Effects of different feeding level on the growth, feed efficiency and body composition of juvenile mangrove red snapper,Lutjanus argentimaculatus(Forsskal 1775)

The effects of several feeding levels (1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% and 4.5% of body weight per day, BW day−1) on the growth, feed efficiency and body composition of juvenile Lutjanus argentimaculatus (body weight 27.1 g) were examined. Fish were fed a test diet (40% protein, 18.4% lipid and 13.4 kJ g−1) for 75 days in three equal meals. Weight gain and specific growth rate increased with increasing feeding level up to 2.5% BW day−1, after which no significant improvement in growth was observed. The feed efficiency, protein efficiency ratio, retention of protein and digestibility of nutrients did not differ for fish fed 1–2.5% BW day−1, but decreased significantly when feeding levels were increased above 3% BW day−1. The chemical compositions of whole fish or body organs were significantly affected by the feeding level. The condition factor, mesenteric fat, hepato- and viscerosomatic indices were higher in fish fed 2.5–4.5% BW day−1. The cholesterol, triglycerides and haematocrit values were similar among treatments, except that high levels of plasma lipids were recorded in fish fed at 2.5% BW day−1. Taking into consideration the growth, feed efficiency and body composition data attained in this study, a feeding level of 2.5% BW day−1 is recommended for juvenile L. argentimaculatus weighing between 27 and 140 g.

Evidence of ontogenetic migration from mangroves to coral reefs by black-tail snapper Lutjanus fulvus: stable isotope approach

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 355:257-266 (2008) - DOI: https://doi.org/10.3354/meps07234 Evidence of ontogenetic migration from mangroves to coral reefs by black-tail snapper Lutjanus fulvus: stable isotope approach Yohei Nakamura1,*, Masahiro Horinouchi3, Takuro Shibuno4, Yoshiyuki Tanaka2, Toshihiro Miyajima2, Isao Koike2, Hisashi Kurokura5, Mitsuhiko Sano5 1Department of Living Marine Resources, and 2Department of Chemical Oceanography, Ocean Research Institute, The University of Tokyo, 1-15-1 Minamidai, Nakano-ku, Tokyo 164-8639, Japan 3Research Center for Coastal Lagoon Environments, Shimane University, 1060 Nishikawatsu-cho, Matsue, Shimane 690-8504, Japan 4Ishigaki Tropical Station, Seikai National Fisheries Research Institute, 148-446, Fukai-Ohta, Ishigaki, Okinawa 907-0451, Japan 5Department of Global Agricultural Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan *Email: ynakamura@ori.u-tokyo.ac.jp ABSTRACT: Mangroves are often considered to be important nurseries for coral reef fishes, yet this assumption has rarely been tested. At Ishigaki Island, southern Japan, black-tail snapper Lutjanus fulvus juveniles often occur in mangroves, whereas subadults and adults are usually found on coral reefs. To test the hypothesis that L. fulvus uses mangroves as a nursery, we conducted stomach content and stable isotope analyses of L. fulvus collected from mangroves and an adjacent coral reef. Stomach content analysis showed that specimens from mangroves fed on mangrove-associated prey, whereas those from the coral reef took coral reef-associated prey, indicating that the species undergoes ontogenetic changes in resource use from the mangroves to the coral reef, i.e. coral reef individuals did not migrate to the mangroves to feed. Stable isotope analysis showed that potential prey and mangrove red snapper L. argentimaculatus (control fish for mangroves) collected from the mangroves had 13C-depleted values of –23 to –17‰, distinct from the –16 to –8‰ values of potential prey and humpback red snapper L. gibbus (control fish for coral reef) collected from the coral reef. δ13C values of L. fulvus in the mangroves had a mangrove signature, whereas individuals on the coral reef gradually shifted from a mangrove signature to a coral reef signature with growth, indicating that small individuals on the coral reef were recent migrants from the mangroves. Based on the δ13C values of the subadult population of L. fulvus on the coral reef, 36 of 41 individuals were estimated to have inhabited the mangroves during their juvenile stage, demonstrating that L. fulvus used the mangroves as a nursery. KEY WORDS: Mangrove · Coral reef · Lutjanidae · Stable isotope analysis · Ontogenetic habitat shift Full text in pdf format PreviousNextCite this article as: Nakamura Y, Horinouchi M, Shibuno T, Tanaka Y and others (2008) Evidence of ontogenetic migration from mangroves to coral reefs by black-tail snapper Lutjanus fulvus: stable isotope approach. Mar Ecol Prog Ser 355:257-266. https://doi.org/10.3354/meps07234Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 355. Online publication date: February 26, 2008 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2008 Inter-Research.

Effects of replacing fishmeal with animal by-products meal supplementation in diets on the growth and nutrient utilization of mangrove red snapper

A feeding trial was conducted for 75 d to evaluate the nutritive value of a mixture of animal by-products (MAB) as a possible protein source in diets for juvenile mangrove red snapper, Lutjanus argentimaculatus (mean initial body weight, 30 g). Fish were fed one of five isonitrogenous diets (40% crude protein) replacing 0, 25% (MAB25), 50% (MAB50), 75% (MAB75) and 100% (MAB100) of fish meal protein with similar percentages of MAB. The MAB consisted of 25% cow liver meal, 20% leather meal, 20% meat and bone meal, 15% blood meal, 10% APC (poultry feather meal), 8% poultry manure dried, 1.5% choline and 0.5% chromic oxide. After 75 d of feeding, fish fed with diets MAB50, MAB75 and MAB100 exhibited significantly lower growth performance than that of fish fed with control and MAB25 diets. The optimum level of MAB was estimated to be 23%. Replacement of fish meal by MAB23% showed the following performance: maximum weight gain, 510%; SGR, 2.39% and FCE, 2.83%. The MAB substitution up to 75% of fish meal protein in diets did not show differences in apparent protein digestibility (83.6% for MAB25, 79.2% for MAB50, 78.7% for MAB75) compared with control (83.4%), whereas in MAB100 group digestibility (65.3%) was significantly lower than in other groups. The apparent phosphorus absorption of test diet groups was significantly higher (37.1% for MAB25, 28.5% for MAB50, 55.6% for MAB75 and 54.5% for MAB100) than that of control (11.2%). The levels of protein and ash in the whole body, carcass and viscera increased as MAB substitution in diets increased, whereas lipids and moisture remained consistent among all treatment groups. These results showed that approximately 23% of fish meal protein could be replaced by a mixture of animal by-products for juvenile snapper growing from 30 g to 167 g in 75 d without compromising growth performance and feed efficiency.

Susceptibility of Fish Species Cultured in Mangrove Brackish Area to Piscine Nodavirus

Susceptibility of orange-spotted grouper Epinephelus coioides, Asian sea bass Lates calcarifer, mangrove red snapper Lutjanus argentimaculatus, milkfish Chanos chanos, and rabbitfish Siganus guttatus to piscine nodavirus from orange-spotted grouper was studied by experimental infection. The fish were intraperitoneally injected with 0.05 mL of the filtrate homogenate of infected organs from diseased grouper at 10 6.8 , 10 5 8 or 10 4 .TCID 50 /fish, while the control group received 0.05 mL of Hanks' balanced salt solution. Clinical signs such as lethargy, anorexia and darkened pigmentation were observed in the orange-spotted grouper, Asian sea bass, mangrove red snapper, and milkfish injected with high and medium doses of the homogenate. Although no or little mortality occurred in the experimentally-infected fish 10 days post-inoculation, viral nervous necrosis specific lesions such as severe necrosis and vacuolation in the brain and retina were produced in these four fish species. The virus was reisolated in SSN-1 cells inoculated with the filtrated tissue homogenate of survivors in all doses for all four fish species. However, in the experimentally infected rabbitfish no histological lesion was observed, and no virus was reisolated. These results indicate that grouper, sea bass, mangrove red snapper, and milkfish are susceptible to the piscine nodavirus isolated from diseased grouper.

Cardicola Short, 1953 and Braya n. gen. (Digenea: Sanguinicolidae) from five families of tropical Indo-Pacific fishes

A survey of Pacific coral reef fishes for sanguinicolids revealed that two species of Lutjanidae (Lutjanus argentimaculatus, L. bohar), six species of Siganidae (Siganus corallinus, S. fuscescens, S. lineatus, S. margaritiferus, S. punctatus, S. vulpinus), seven species of Chaetodontidae (Chaetodon aureofasciatus, C. citrinellus, C. flavirostris, C. lineolatus, C. reticulatus, C. ulietensis, C. unimaculatus), three species of Scombridae (Euthynnus affinis, Scomberomorus commerson, S. munroi) and three species of Scaridae (Chlorurus microrhinos, Scarus frenatus, S. ghobban) were infected with morphologically similar sanguinicolids. These flukes have a flat elliptical body, a vestigial oral sucker, a single testis, separate genital pores and a post-ovarian uterus. However, these species clearly belong in two genera based on the position of the testis and genital pores. Sanguinicolids from Lutjanidae, Siganidae, Chaetodontidae and Scombridae belong in Cardicola Short, 1953; the testis originates anteriorly to, or at the anterior end of, the intercaecal field and does not extend posteriorly to it, the male genital pore opens laterally to the sinistral lateral nerve chord and the female pore opens near the level of the oötype (may be anterior, lateral or posterior to it) antero-dextral to the male pore. Those from Scaridae are placed in a new genus, Braya; the testis originates near the posterior end of the intercaecal field and extends posteriorly to it, the male pore opens medially at the posterior end of the body and the female pore opens posterior to the oötype, antero-sinistral to the male pore. The second internal transcribed spacer (ITS2) of ribosomal DNA from these sanguinicolids and a known species, Cardicola forsteri Cribb, Daintith & Munday, 2000, were sequenced, aligned and analysed to test the distinctness of the putative new species. Results from morphological comparisons and molecular analyses suggest the presence of 18 putative species; 11 are described on the basis of combined morphological and molecular data and seven are not because they are characterised solely by molecular sequences or to few morphological specimens (n=one). There was usually a correlation between levels of morphological and genetic distinction in that pairs of species with the greatest genetic separation were also the least morphologically similar. The exception in this regard was the combination of Cardicola tantabiddii n. sp. from S. fuscescens from Ningaloo Reef (Western Australia) and Cardicola sp. 2 from the same host from Heron Island (Great Barrier Reef). These two parasite/host/location combinations had identical ITS2 sequences but appeared to differ morphologically (however, this could simply be due to a lack of morphological material for Cardicola sp. 2). Only one putative species (Cardicola sp. 1) was found in more than one location; most host species harboured distinct species in each geographical location surveyed (for example, S. corallinus from Heron and Lizard Islands) and some (for example, S. punctatus, S. fuscescens and Chlorurus microrhinos) harboured two species at a single location. Distance analysis of ITS2 showed that nine species from siganids, three from scombrids and five from scarids formed monophyletic clades to the exclusion of sanguinicolids from the other host families. Cardicola milleri n. sp. and C. chaetodontis Yamaguti, 1970 from lutjanids and chaetodontids, respectively, were the only representatives from those families that were sequenced. Within the clade formed by sanguinicolids from Siganidae there was a further division of species; species from the morphologically similar S. fuscescens and S. margaritiferus formed a monophyletic group to the exclusion of sanguinicolids from all other siganid species.

Isolation and characterization of microsatellite loci from mangrove red snapper Lutjanus argentimaculatus

Abstract Lutjanus argentimaculatus, also called mangrove red snapper, is a commercially important fish in East Asia. A proper understanding of population structure is primarily linked with the management of genetic resources in exploiting marine fisheries. Herein, seven microsatellite loci, which showed high polymorphism (observed heterozygosity per locus ranging from 0.3571 to 0.7857 and expected heterozygosity per locus ranging from 0.6236 to 0.8821), were isolated and characterized from L. argentimaculatus. Cross‐species amplifications also indicate that primers designed for these loci may be useful for further studies about other closely phylogenetic species of the family Lutjanidae.

Monogenea of marine fishes from Hainan Island, China. VIII. Two new species of Euryhaliotrema Kritsky & Boeger, 2002 (Dactylogyridae) from Lutjanus argentimaculatus (Teleostei: Lutjanidae)

This paper reports two new species of Euryhaliotrema Kritsky & Boeger, 2002 collected from the gills of Lutjanus argentimaculatus (Forsskål). E. xinyingense n. sp. is similar to Euryhaliotrema atlanticum Kritsky & Boeger, 2002 in the structure of copulatory apparatus, but differs from the latter in the shape of anchors and the structure of vagina. E. hainanense n. sp. also closely resembles E. atlanticum Kritsky & Boeger, 2002, but differs from the latter in the structure of haptor and the shape of accessory piece.

Species identification in salted products of red snappers by semi-nested PCR-RFLP based on the mitochondrial 12S rRNA gene sequence

A molecular approach was developed to distinguish species of red snappers among commercial salted fish products. The specific fragments of the mitochondrial 12S rRNA gene, which were about 450bp, were obtained using the semi-nested polymerase chain reaction (semi-nested PCR). Subsequently, PCR amplicons were sequenced, aiming to select restriction endonucleases that generated species-specific restriction fragment length polymorphism (RFLP) profiles. Discrimination of red snappers Lutjanus sanguineus, Lutjanus erythopterus from Lutjanus argentimaculatus, Lutjanus malabarius and other morphologically similar fishes such as Lethrinus leutjanus and Pinjalo pinjalo was feasible by one restriction digestion reaction with three endonucleases Hae III, Sca I and SnaB I, however, for discrimination of L. sanguineus and L. erythopterus, another restriction digestion reaction with single restriction endonuclease Mae II was needed. The semi-nested PCR-RFLP was demonstrated to be reliable in species identification of salted fish products in this study.