Redfin

A series of 14 day experiments was conducted on five common New Zealand fish species (redfin bully Gobiomorphus huttoni, inanga Galaxias maculatus, brown trout Salmo trutta, longfin eel Anguilla dieffenbachii and koaro Galaxias brevipinnis) to assess the effect of pH on survival and changes in body mass. No species survived in water of pH <4 although there was 100% survival of all adults at pH 4.5, G. maculatus larvae were also tested and had high mortality at this pH. Results suggest that adults are tolerant of low-pH waters; however, successful remediation of anthropogenically acidified streams will require an understanding of the susceptibility to low pH on different life cycle stages...

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Animals exhibit diel periodicity in their activity in part to meet energy requirements whilst evading predation. A competing hypothesis suggests that partitioning of diel activities is less important because animals capitalise on opportunity. To test these hypotheses we examined the diel activity patterns for two cyprinid minnows, chubbyhead barb Barbus anoplus and the Eastern Cape redfin minnow Pseudobarbus afer that both occur within headwater streams in the Eastern Cape, South Africa. Chubbyhead barbs exhibited consistent nocturnal activity based on both field and laboratory observations...

Chanodichthys mongolicus is a ferocious carnivorous species in the family Cyprinidae, which has a high economic value in freshwater aquaculture species. In the present study, we report the complete mitochondrial genome of C. mongolicus, comparing with two different individuals of C. mongolicus and phylogenetic analysis with closely related species. The complete mitochondrial genome of C. mongolicus was 16,622 bp, and it contained 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, a control region (D-loop) and an L-strand replication origin (OL)...

This study evaluated the effect of ramp length and slope on fish passage over baffled ramps with 15° and 30° gradients. Three fish species indigenous to New Zealand were tested: the redfin bully Gobiomorphus huttoni, the common bully Gobiomorphus cotidianus and the inanga Galaxias maculatus with ramp lengths of 3, 4·5 and 6 m. As slope and ramp length increased, passage success rate decreased for G. maculatus and G. cotidianus. At a slope of 15°, both G. maculatus and G. cotidianus could pass all ramp lengths tested with the highest success rate on the 3 m ramp...

We studied the morphology and diversity of retinal ganglion cells in the Pacific redfin, Tribolodon brandtii. These cells were retrogradely labeled with horseradish peroxidase and examined in retinal whole mounts. A sample of 203 cells was drawn with a camera lucida. A total of 19 structural parameters were estimated for each cell, and a variety of clustering algorithms were used to classify the cells. The optimal solution was determined by using silhouette analysis. It was based on three variables associated with dendritic field size and dendrite stratification in the retina...

Monglian redfin is a kind of freshwater aquaculture species which has an important economic value in China. In this study, we report the complete sequence of mitochondrial genome of Monglian redfin. The complete mitochondrial genome sequence is determined to be 16,621 base pairs (bp) in length and contain 13 protein-coding gene (PCGs), 22 transfer RNA genes, large (rrnL) and small (rrnS) ribosomal RNA, and the non-coding control region. Its total A+T content is 55.98%. We also analyzed the structure of control region, six conserved sequence blocks (CSBs) (CSB-1, CSB-2, CSB-3, CSB-D, CSB-E and CSB-F) and one potential termination-associated sequence were detected and the control region also included a 2-bp tandem repeat with eight repeat times...

MtDNA variations were examined in four endemic species of the Far Eastern redfins of the genus Tribolodon across considerable parts of their ranges. No close correlation was revealed between the lifespan of the species and the level of mtDNA variations. An association was revealed between the degree of manifestation of the genetic structure population and the degree ofamphidromy in the species. The presence of differing mtDNA phylogroups in three out of four species indicates that the history of these species included long period of independent intraspecific divergent evolution...

The ranavirus, epizootic hematopoietic necrosis virus (EHNV), is endemic to southern Australia with natural outbreaks resulting in mass mortality events in wild Redfin Perch Perca fluviatilis (also known as Eurasian Perch) and less severe disease in farmed Rainbow Trout Oncorhynchus mykiss. To further investigate the host range for EHNV, 12 ecologically or economically important freshwater fish species from southeastern Australia were exposed experimentally to the virus. A bath-challenge model at 18 ± 3°C was employed with limited use of intraperitoneal inoculation to determine if a species was likely to be susceptible to EHNV...

By using a set of pelagic gillnets with eight mesh sizes, an investigation was made on the spatial distribution of small fishes in submerged macrophyte habitats in a shallow macrophytic lake (Niushan Lake) in the middle reach of Yangtze River in summer, 2005. The fish composition, abundance, and size structure were examined along a biomass gradient of the most dominant submerged macrophyte Potamogeton maackianus. A total of 1124 individuals from 13 fish species were caught during the study period. According to the abundance and occurrence, sharpbelly Hemiculter leucisculus and redfin culter Cultrichthys erythropterus were identified as the two dominant small pelagic fishes in the lake...

Considerable differences in karyotypes of Tribolodon hakonensis from Primorye and the rivers of the Sea of Okhotsk drainage were demonstrated. These differences raise doubts that these fishes belong to one species and point to the necessity of more precise definition of the species status of the southern form of T. hakonensis. The karyological evidence is consistent with the data of mtDNA PCR-RFLP analysis on genetic independence of the southern and the northern forma of T. hakonensis. In the northern form of T hakonensis, variation of the chromosomal arm number was revealed...

Analysis of mtDNA variation in one of the amphidromic Far Eastern redfins, Tribolodon hakonensis, revealed the presence of three considerably genetically different mtDNA phylogroups in the individuals from the Russian part of the range. These data suggest the presence of the two periods of divergent evolution in the history of the species examined. Comparison of the haplotype distributions from different phylogroups over the species range revealed geographic localization of only one phylogroup in the population samples from southern continental coastal regions of the Sea of Japan...

A chemoattractant lectin from the dorsal spines of the redfin velvetfish, Hypodytes rubripinnis, was isolated using a combination of affinity chromatography techniques. The glycoprotein, with a molecular mass of 110 kDa, is named Karatoxin. Karatoxin caused agglutination of rabbit erythrocytes. This agglutination was effectively inhibited by D-mannose. In addition, Karatoxin exhibited not only mitogenic activity in the presence of murine splenocytes, but also chemotactic activity in the presence of guinea-pig neutrophils and macrophages...

A challenge model for comparison of the virulence of epizootic haematopoietic necrosis virus (EHNV) to European stocks of redfin perch, Perca fluviatilis L., and rainbow trout, Oncorhynchus mykiss (Walbaum), was tested. The model investigated intraperitoneal (IP), bath and cohabitation routes at 10, 15 and 20 degrees C for 5-6 g fish and 15 degrees C for 20 g perch. In the IP challenges of perch, significant mortality occurred at 15 degrees C and 20 degrees C. In challenge trials for rainbow trout, significant mortalities were observed in IP and bath challenges at 20 degrees C...

Epizootic haematopoietic necrosis virus (EHNV), Bohle iridovirus (BIV) and Wamena virus (WV) cause serious diseases in fish, amphibians and snakes, respectively but are restricted to Australasia. European catfish virus (ECV) and sheatfish virus (ESV) have caused epizootics in fish on farms in continental Europe. Currently there are no simple or readily available methods to distinguish these viruses, which are in the Iridoviridae. They are culturally, morphologically and antigenically very similar to Frog Virus 3 (FV3), the type species in Ranavirus in this family and Gutapo virus (GV), another amphibian ranavirus from America...

Radiocesium (137Cs) concentrations were determined during 1974, 1981 and 1998 for seven species of fish inhabiting a stream (Steel Creek) contaminated by effluents from a nuclear reactor to examine the decline of this radionuclide in a natural ecosystem. Median 137Cs concentrations were highest in Micropterus salmoides (largemouth bass) during each year of the investigation (1974 = 6.67 Bq g(-1) dry wt. of whole body; 1981 = 3.72 Bq g(-1); 1998 = 0.35 Bq g(-1)), but no patterns of differences were observed among Aphredoderus sayanus (pirate perch), Esox americanus (redfin pickerel), Lepomis auritus (redbreast sunfish), L...

The Berg River redfin (Pseudobarbus burgi) is a critically endangered endemic cyprinid from South Africa. We investigated mitochondrial DNA control region variation among specimens representative of five populations drawn from two adjacent river systems. Phylogenetic analyses, a minimum spanning network, and an analysis of molecular variance underscore the pronounced genetic separation of redfins originating from the geographically closely allied Verlorevlei and Berg Rivers, two populations that may have remained isolated since the Pleistocene...

Epizootic haematopoietic necrosis virus (EHNV) is an iridovirus confined to Australia and is known only from rainbow trout Oncorhynchus mykiss and redfin perch Perca fluviatilis. Outbreaks of disease caused by EHNV in trout populations have invariably been of low severity, affecting only 0+ post-hatchery phase fingerlings < 125 mm in length. To date the virus has been demonstrated in very few live in-contact fish, and anti-EHNV antibodies have not been found in survivors of outbreaks, suggesting low infectivity but high case fatality rates in trout...

Iridovirus-like agents isolated from systemic infected fish (Silurus glanis, SFIR; Ictalurus melas, CFIR I, CFIR II, CFIR III) and from frogs (Rana esculenta, REIR) in Europe, Epizootic Haematopoietic Necrosis Virus (EHNV) isolated in Australia from redfin perch (Perca fluviatilis), and Frog Virus 3 (FV 3) isolated from frogs (Rana pipiens) in the USA were investigated by electron microscopy, polypeptide composition, immunofluorescence, restriction endonuclease digestion, Southern-blot hybridization and polymerase chain reaction (PCR) amplification...

Experimental transmission of epizootic haematopoietic necrosis virus (EHNV) to adult redfin perch Perca fluviatilis and juvenile rainbow trout Oncorhynchus mykiss was undertaken at different water temperatures using intraperitoneal (IP) and bath inoculation. Redfin perch were highly susceptible to EHNV by both routes of infection. Bath inoculation with as few as 0.08 TCID50.mL-1 was lethal. The incubation period in redfin perch was about 11 days at a water temperature of 19-21 degrees C but was longer at colder temperatures and disease did not occur at temperatures below 12 degrees C...