The genus Ceratothoa Dana, 1852, is revised for Australian waters. Ceratothoa is represented in Australia by nine species, including two new species: Ceratothoa barracuda sp. nov. described from Cairns and Ceratothoa globulus sp. nov. described from Lord Howe Island. Ceratothoa imbricata Fabricius, 1775 is redescribed, with Ceratothoa trillesi (Avdeev, 1979) and Ceratothoa huttoni Filhol, 1885 placed into junior synonymy; the preferred hosts are species of the genus Trachurus (Carangidae). Ceratothoa banksii (Leach, 1818) is validated and brought out of synonymy with Ceratothoa imbricata; host species are from the families Kyphosidae, Scombridae, Latridae, Carangidae, Mugilidae, Salmonidae, Scatophagidae, Pomatomidae and Hemiramphidae. Species excluded from the Australian fauna are Ceratothoa trigonocephala (Leach, 1818) with an unknown host identity and type locality; and Ceratothoa lineata Miers, 1876a, that here is transferred to the genus Mothocya Costa, 1851, with Mothocya ihi Bruce, 1986 placed into junior synonymy. Ceratothoa contracta (Miers, 1880), the New Zealand Ceratothoa novaezelandiae Filhol, 1885 and the East Pacific Ceratothoa gaudichaudii (Milne Edwards, 1840) are regarded here as species inquirenda. A key to the Australian species of Ceratothoa is presented.
This study aimed to determine the effects of 2-5 wash cycles and the addition of tetrasodium pyrophosphate (TSPP) (0 %, 0.05 Surimi% and 0.1 % w/w)-with or without the addition of 0.4 % calcium chloride (CaCl2)-on the physical properties such as texture, colour, expressible moisture and microstructure of Cobia (Rachycentron canadum) surimi gel. The highest breaking force (484.85 g) was obtained with the addition 0.1 % TSPP alone on the fifth wash. However, a combination of 0.1 and 0.4 % CaCl2 in surimi gels at wash cycle 5 resulted in the highest degree of whiteness (86.8 %), as well as total expressible moisture (2.785 %) and deformation (17.11 mm). The highest surimi gel strength (6,923 g.mm) was obtained after three wash cycles with the addition of 0.1 % TSPP +0.4 % CaCl2. The physical properties of Cobia fish surimi gels were affected by the number of wash cycles and treatments with TSPP and CaCl2.
A new species of Larimichthys from Terengganu, east coast of Peninsular Malaysia is described from specimens collected from the fish landing port at Pulau Kambing, Kuala Terengganu. Larimichthys terengganui can be readily distinguished from other species of the genus by having an equally short pair of ventral limbs at the end of the gas bladder appendages, which do not extend lateral-ventrally to the lower half of the body wall, and fewer dorsal soft rays (29-32 vs. 31-36) and vertebrae (24 vs. 25-28). Larimichthys terengganui can be distinguished from L. polyactis and L. crocea by having a gill raker at the angle of first gill arch shorter than the gill filament. Furthermore, the second anal spine in L. terengganui is equal or slightly shorter than eye diameter (vs. shorter in L. polyactis); L. terengganui has 8-9 anal soft rays (vs. only 7 in L. pamoides). Snout length of L. terengganui is greater than eye diameter, whereas in L. crocea the snout is shorter than eye diameter. A key to species of Larimichthys is provided. All obtained specimens of the species were recorded from Terengganu waters, east coast of Peninsular Malaysia.
Matched MeSH terms: Perciformes/anatomy & histology; Perciformes/classification*; Perciformes/growth & development
Cobia Rachycentron canadum, is one of the emerging aquaculture species but is usually a non-target resource in fisheries
industry and within Malaysia, their landings are among the highest worldwide. Identification of stocks with unique
morphological characters is important for effective management and sustainable utilization. Morphometric variations
among three different cobia populations from Kedah, Terengganu and Johor were studied. All the morphometric
characteristics varied among the three populations as all the elements of the first Eigen vector were positive. Discriminant
analysis suggested that head depth (HD) and maximum body depth, (MaxD) were the most varied among the populations.
Cobia populations from Kedah and Johor were in a single cluster in the dendrogram with a 63.69% similarity while
Terengganu was in another cluster with a similarity of 8.01% from Kedah and Johor. The differences in the observed
morphometry may be resulted from different trophic activities and/or habitat productiveness explored by each of the
populations
The complete mitochondrial genomes of four fish species of the commercially important family Latidae were sequenced using the Illumina MiSeq, thereby significantly increasing the mitogenomic resources for the family. Whole mitogenome-based phylogenetic analysis supports the monophyly of the genus Lates and more generally the family Latidae. The mitogenome sequences from this study will be useful for future assessments of the diversity within and between Lates species and studies of phylogenetic relationships within the diverse and taxonomically challenging perciform fishes.
The Asian seabass (Lates calcarifer) is one of the most economically important aquaculture fish species in South East Asia. While the biology of the Asian seabass is widely studied, relatively little information is available at the molecular level. This lack of molecular information represents one obstacle to rapid progress in the study of immune responses particularly under aquaculture conditions. In light of this situation, we have undertaken an expressed sequence tag (EST) project on the Asian seabass spleen, the secondary lymphoid organ, for the identification of immune-related genes. A
total of 2932 ESTs were generated and grouped into 1063 unique transcripts (UTs), which consisted of 104 consensi and 959 singletons. Of these, 51.3% (545/1063) matched to previously identified genes, while 48.7% (518/1063) showed no match. Of the 545 homologous UTs, 102 (9.6%) can be putatively identified as immune-related genes. The identification of the putative immune-related genes provides a meaningful framework in the effort to comprehend the Asian seabass immune system that may lead to an increase in the understanding of the defense mechanisms of and our abilities to
manage this fish species.
Management of wild fisheries resources requires accurate knowledge on which species are being routinely exploited, but it can be hard to identify fishes to species level, especially in speciose fish groups where colour patterns vary with age. Snappers of the genus Lutjanus represent one such group, where fishes can be hard to identify and as a result fisheries statistics fail to capture species-level taxonomic information. This study employs traditional morphological and DNA barcoding approaches to identify adult and juvenile Lutjanus species harvested in Malaysian waters. Our results reveal a suite of species that differs markedly from those that have previously been considered important in the Malaysian wild-capture fishery and show that official fisheries statistics do not relate to exploitation at the species level. Furthermore, DNA barcoding uncovered two divergent groups of bigeye snapper ('Lutjanus lutjanus') distributed on either side of the Malay Peninsula, displaying a biogeographical pattern similar to distributions observed for many co-occurring reef-distributed fish groups. One of these bigeye snapper groups almost certainly represents an unrecognized species in need of taxonomic description. The study demonstrates the utility of DNA barcoding in uncovering overlooked diversity and for assessing species catch composition in a complicated but economically important taxonomic group.
Matched MeSH terms: Perciformes/classification*; Perciformes/genetics*; Perciformes/growth & development
Taxonomic confusion exists within the genus Epinephelus due to the lack of morphological specializations and the overwhelming number of species reported in several studies. The homogenous nature of the morphology has created confusion in the Malaysian Marine fish species Epinephelus fuscoguttatus and Epinephelus hexagonatus. In this study, the partial DNA sequence of the 16S gene and mitochondrial nucleotide sequences of two gene regions, Cytochrome Oxidase Subunit I and III were used to investigate the phylogenetic relationship between them. In the phylogenetic trees, E. fuscoguttatus was monophyletic with E. hexagonatus species and morphology examination shows that no significant differences were found in the morphometric features between these two taxa. This suggests that E. fuscoguttatus is not distinguishable from E. hexagonatus species, and that E. fuscoguttatus have been identified to be E. hexagonatus species is likely attributed to differences in environment and ability to camouflage themselves under certain conditions. Interestingly, this finding was also supported by Principal Component Analysis on Attenuated Total Reflectance-Fourier-transform Infrared (ATR-FTIR) data analysis. Molecular, morphological and meristic characteristics were combined with ATR-FTIR analysis used in this study offer new perspectives in fish species identification. To our knowledge, this is the first report of an extensive genetic population study of E. fuscoguttatus in Malaysia and this understanding will play an important role in informing genetic stock-specific strategies for the management and conservation of this highly valued fish.
The mitogenome of the Australian freshwater blackfish, Gadopsis marmoratus was recovered coverage by genome skimming using the MiSeq sequencer (GenBank Accession Number: NC_024436). The blackfish mitogenome has 16,407 base pairs made up of 13 protein-coding genes, 2 ribosomal subunit genes, 22 transfer RNAs, and a 819 bp non-coding AT-rich region. This is the 5th mitogenome sequence to be reported for the family Percichthyidae.
The mitogenome of an Australian sample of the mudskipper, Periophthalmus minutus, was recovered from partial sequencing using the MiSeq sequencer. This mudskipper has a mitogenome of 16,506 base pairs (55% A + T content) made up of two ribosomal subunit genes, 13 protein-coding genes, 22 transfer RNAs, and a 838 bp non-coding AT-rich region. This is the first sequenced mitogenome for the genus Periophthalmus and the fifth for the subfamily Oxudercinae.
Culturing fishes in marine cages is a rapidly developing area of marine aquaculture. The Asian seabass Lates calcarifer (Bloch) is a fast growing good quality fish that is readily cultured in intensive systems in the South Asian region and in Malaysia in particular. Although several papers have been published to date on viral, bacterial, parasitic and fungal organisms causing diseases in the Asian seabass, the occurrence of a coccidian infection in this species has only recently been recorded. We collected sporulated and unsporulated oöcysts of a new species of Goussia Labbé, 1986, from the mucus covering the epithelium of the intestine of L. calcarifer. This paper provides a description of Goussia kuehae n. sp. Sporulated oöcysts of this species are ellipsoidal, 37-40 μm in length and 28-30 μm in width. The ellipsoidal sporocysts are relatively small, 15.2-17 × 5.7-8 μm, and located loosely in the oöcyst. There are residual bodies both in the oöcysts and the sporocysts. Goussia kuehae n. sp. differs from all known species of Goussia in the large size of the oöcysts and in having two types of oöcyst residuum.
Histamine, putrescine cadaverine and cis-urocanic acid (UCA) have all been implicated or suggested in scombroid fish poisoning. However, there is little information on UCA especially during storage. Changes in their contents during storage of whole Indian mackerel at 0, 3±1, 10±1 for up to 15 days and 23±2°C for up to 2 days were monitored. Fresh muscles contained 14.83 mg/kg trans-UCA, 2.23 mg/kg cis-UCA and 1.86 mg/kg cadaverine. Histamine and putrescine were not detected. After 15 days at 0 and 3°C, trans-UCA content increased to 52.83 and 189.51 mg/kg, respectively, and decreased to <2 mg/kg at the other two temperatures. Storage at 10°C also resulted in an increase in trans-UCA after 3 days, only to decrease after 6 days. The concentration of cis-UCA increased nearly 13-fold after 15 days at 0 and 3°C, decreased at 10°C and remained unchanged at 23°C. Histamine, putrescine and cadaverine levels increased significantly (P value<0.05) at all temperatures especially at 23°C.
During several surveys made in the region of the lower Fly River and delta, Papua New Guinea, nine species of oxudercine gobies (Gobiidae: Oxudercinae) were recorded: Boleophthalmus caeruleomaculatus, Oxuderces wirzi, Periophthalmodon freycineti, Periophthalmus darwini, Periophthalmus novaeguineaensis, Periophthalmus takita, Periophthalmus weberi, Scartelaos histophorus and Zappa confluentus. An exploratory multivariate analysis of their habitat conditions discriminated five guilds, differentially distributed in habitats with different quantities of environmental water and three guilds corresponding to different levels of salinity. A partial correspondence between phylogenetic and ecological categories suggested the presence of parallel adaptive radiations within different genera. In particular, the species found in the most terrestrial habitats (P. weberi) was also found in the widest range of conditions, suggesting that colonization of extreme semi-terrestrial and freshwater habitats by this species was facilitated by eurytypy. It is proposed that these findings provide insight into convergent adaptations for the vertebrate eco-evolutionary transition from sea to land.
One new and three previously described species of Trianchoratus Price et Berry, 1966 were collected from the gills of Channa lucius (Cuvier) and Channa striata (Bloch) from the Bukit Merah Reservoir, Perak and Endau-Rompin, Pahang, Peninsular Malaysia. They are Trianchoratus longianchoratus sp.n., T. malayensis Lim, 1986 and T. pahangensis Lim, 1986 from C. lucius, and T. ophicephali Lim, 1986 from C. striata. The new species differs from the Trianchoratus species hitherto described from channids and anabantoids in having two ventral anchors with a long curved inner root and one dorsal anchor with a curved inner root and lacking an outer root. A table summarizing the known species of heteronchocleidins (Trianchoratus, Eutrianchoratus and Heteronchocleidus) and Sundanonchus reported from fish hosts of different families (Channidae, Helostomatidae, Anabantidae and Osphronemidae) is provided.
Numerous specimens of Ancyrocephaloides triacanthi Yamaguti, 1938 and A. chauhani Bychowsky & Nagibina, 1975 were collected from two triacanthid fishes, Triacanthus biaculeatus and Tripodichthys blochii, off Peninsular Malaysia. The two monogenean species are redescribed and considered to be the only valid species of Ancyrocephaloides Yamaguti, 1938. Examinations of these worms revealed new features, e.g. the presence of exudates (both net-like and bundle-like) and superficial grooves in the anchors in both species, which necessitated re-descriptions of the two species and amendments to the generic diagnosis. Both species have relatively small anchors with two lateral superficial grooves along the shaft and point, peduncular glands and four large, pyriform secretory reservoirs in the peduncular-haptoral region, each with a single tubular extension to an associated anchor, and net-like structures (exudate) attached to the anchors. The net-like structures are one of the external manifestations of the secretion produced in the peduncular glands and stored in the pyriform secretory reservoirs. When released within the gill-tissue of the host, the exudate is in the form of bundles which extend within the gill-filament. The small anchors convey secretions from the secretory reservoirs via lateral superficial grooves into the gills as the anchors pierce the host tissue for attachment. The secretion coagulates as left and right thread-like bundles of exudate within the gill tissues and is only apparent as nets when it is released into the surrounding water. The recurved point of the anchor and position of the point of exudation allow the nets to remain attached to the anchor point, even after the detachment of the anchors from the gill tissue. This exudate possibly acts somewhat like a 'belay device' or 'safety belt', preventing the parasite from being washed away by the respiratory current during the onset of its leech-like locomotion, as well as assist the relatively small anchors in attachment.
Two known and two new species of Diplectanocotyla Yamaguti, 1953 (D. gracilis Yamaguti, 1953, D. megalopis Rakotofiringa & Oliver, 1987, D. langkawiensis n. sp. and D. parva n. sp.) were collected from Megalops cyprinoides (Megalopidae) off Langkawi, Kedah and Matang, Perak, Peninsular Malaysia. All four species possess similar types of sclerotised male and female reproductive structures and similar soft anatomical features. The squamodisc sclerites of all four species have spine-like projections with varying degrees of visibility and shapes (sharp-pointed to triangular). In D. megalopis and D. langkawiensis n. sp. the spines are sharp-pointed and distinct on sclerites from rows 5-6 onwards. In D. gracilis and D. parva n. sp. the sclerite spines are triangular, lightly sclerotised and occur on almost all of the sclerites. D. parva n. sp. has comparatively the smallest set of anchors, bars, squamodiscs and squamodisc suckers. The anchors and bars of the other three species are almost similar in overall size, and the main distinguishing feature is the relative lengths of the inner and outer roots of the ventral anchors. In D. gracilis the outer root is very much smaller than the inner root and they are disposed almost at a right angle to each other. In D. megalopis the outer root is usually about half the length of the inner root and the roots are inclined at c.60 degrees to each other. In D. langkawiensis n. sp. the roots are inclined at c.40 degrees degrees and the outer root is of a similar length or only slightly shorter than the inner root. The openings of the two squamodisc suckers of all four Diplectanocotyla species are surrounded by tiny scale-like spines. Bifid tegumental spines are found in the posterior region of all four species, differing only in their extent: in D. parva n. sp. the tegumental spines are only distributed in the peduncular region and not beyond, whilst in the other three species the tegumental spines extend from the posterior level of the testis to the end of the peduncle. An amended diagnosis of Diplectanocotyla and a key to its species are appended.
Sixteen labrid species, including four Bodianus spp., were examined in New Caledonia (South Pacific) and monogeneans were found only on Bodianus perditio (Quoy et Gaimard). This species, Haliotrema banana sp. n., is the second Haliotrema species to be described from the labrids, the first being Haliotrema bodiani Yamaguti, 1968 from Bodianus albotaeniatus (Valenciennes), previously designated as B. bilunulatus (Lacépède). The new species is similar to H. bodiani in soft reproductive parts but differs from it in the morphologies of the hard haptoral parts, mainly in the shape of the dorsal bar (bar-shaped vs V-shaped in H. bodiani) and ventral bar. It is similar to Haliotrema spirale Yamaguti, 1968 and Haliotrema minutospirale Yamaguti, 1968 in the shape of the anchors and bars but differs from them in the detailed structures of the copulatory organ and vaginal system.
Giant grouper (Epinephelus lanceolatus) is a commercially important species, but its wild population has recently been classified as vulnerable. This species has significant potential for use in aquaculture, though a greater understanding of population genetics is necessary for selective breeding programs to minimize kinship for genetically healthy individuals. High-throughput pyrosequencing of genomic DNA was used to identify and characterize novel tetra- and trinucleotide microsatellite markers in giant grouper from Sabah, Malaysia. In total, of 62,763 sequences containing simple sequence repeats (SSRs) were obtained, and 78 SSR loci were selected to possibly contain tetra- and trinucleotide repeats. Of these loci, 16 had tetra- and 8 had trinucleotide repeats, all of which exhibited polymorphisms within easily genotyped regions. A total of 143 alleles were identified with an average of 5.94 alleles per locus, with mean observed and expected heterozygosities of 0.648 and 0.620, respectively. Among of them, 15 microsatellite markers were identified without null alleles and with Hardy-Weinberg equilibrium. These alleles showed a combined non-exclusion probability of 0.01138. The probability of individual identification (PID) value combined with in descending order 12 microsatellite markers was 0.00008, which strongly suggests that the use of the microsatellite markers developed in this study in various combinations would result in a high resolution method for parentage analysis and individual identification. These markers could be used to establish a broodstock management program for giant grouper and to provide a foundation for genetic studies such as population structure, parentage analysis, and kinship selection.
Genetic variability and differences in wild striped snakehead Channa striata from Malaysia were analysed by genotyping nine novel nuclear microsatellite loci. Analysis revealed moderate-to-high genetic diversity in most of the populations, indicative of large effective population sizes. The highly diversified populations are admixed populations and, therefore, can be recommended as potential candidates for selective breeding and conservation since they each contain most of the alleles found in their particular region. Three homogenous groups of the wild populations were identified, apparently separated by effective barriers, in accordance with contemporary drainage patterns. The highest population pairwise FST found between members of the same group reflects the ancient population connectivity; yet prolonged geographical isolation resulted in adaptation of alleles to local contemporary environmental change. A significant relationship between genetic distance and geographical isolation was observed (r = 0·644, P < 0·01). Anthropogenic perturbations indicated apparent genetic proximity between distant populations.
Phylogeographic patterns and population structure of the pelagic Indian mackerel, Rastrelliger kanagurta were examined in 23 populations collected from the Indonesian-Malaysian Archipelago (IMA) and the West Indian Ocean (WIO). Despite the vast expanse of the IMA and neighbouring seas, no evidence for geographical structure was evident. An indication that R. kanagurta populations across this region are essentially panmictic. This study also revealed that historical isolation was insufficient for R. kanagurta to attain migration drift equilibrium. Two distinct subpopulations were detected between the WIO and the IMA (and adjacent populations); interpopulation genetic variation was high. A plausible explanation for the genetic differentiation observed between the IMA and WIO regions suggest historical isolation as a result of fluctuations in sea levels during the late Pleistocene. This occurrence resulted in the evolution of a phylogeographic break for this species to the north of the Andaman Sea.