Reproductive biology of a riverine cyprinid,Labeo umbratus (Teleostei: Cyprinidae), in small South African reservoirs

The reproductive and recruitment characteristics of moggel, Labeo umbratus, populations were examined in four small South African reservoirs. Reproduction, characterised by an extended spawning season, high fecundity, short incubation time and rapid larval development, appears to be ideally suited to the highly variable environment of small reservoirs. Evidence suggested that L. umbratus spawns in the reservoirs. In two reservoirs where samples were conducted monthly, GSI (gonado-somatic index) was positively correlated with both water temperature and day length, whilst the CPUE (catch per unit effort) of juveniles was not related to any environmental variable. The success of moggel spawning appeared to increase when there was early spring and consistent summer rainfall.     

The haemoglobins of Labeo umbratus (Smith) and Labeo capensis (Smith)

The haemoglobins of both L. umbratus and L. capensis separated into four components on polyacrylamide electrophoresis. The isoelectric points of these fractions were found to be 9.35, 6.89, 6.63 and 6.40. Organic nucleotide triphosphate concentration in the blood of L. capensis was found to be 56.72 ± 18.01 mg% and 58.72 ± 17.9 mg% in the case of L. umbratus . It is not possible to distinguish between L. umbratus and L. capensis purely on the basis of the haemoglobin electropherogram.     

The plasma proteins of Labeo umbratus (Smith) and Labeo capensis (Smith)

The plasma proteins of L. umbratus and L. capensis have been investigated by means of cellulose-acetate and polyacrylamide gel electrophoresis. Characteristic patterns were obtained for each specie although variations occur within a certain basic framework. Certain fractions were further isolated and approximate average molecular weights were found to vary between 55 000 and above 120 000 and isoelectric points between 5.78 and 4.2. Certain fractions were found to exist in dimeric form. It is concluded that the application of the human nomenclature to fish plasma protein fractions is of dubious value and that the fish fractions can only be classified after thorough biochemical investigation.     

Electrophoresis of haemoglobin in single erythrocytes of Labeo umbratus (Smith) and Labeo capensis (Smith)

Electrophoresis of haemoglobin in single erythrocytes of Labeo umbratus and Labeo capensis showed that haemoglobin behaved in three distinct ways in both species. The majority of cells contained haemoglobin which moved as a broad band towards the anode. In a few cells haemoglobin moved towards both the anode and the cathode and in even fewer cells, haemoglobin moved as a sharp band to either the cathode or anode. These results are discussed in relation to other observations.     

Partial separation of the pituitary proteins of Labeo umbratus, Smith (mudfish)

L. umbratus pituitary glands were partially separated by means of preparative polyacry-lamide electrophoresis and chromatography on DEAE-cellulose and Sephadex G-50. Eight fractions were obtaìned and it was found that fraction 1 contained potent adrenocorticotropic stimulating activity, with a molecular weight in the region of 6000. Fractions 3 and 4 contained potent gonadotropic and a lesser degree of exopthalmic producing activity, with molecular weights in the region of 14 000 to 20 000. Fraction 6 displayed pigeon-crop stimulating activity, with a molecular weight above 30 000. Fractions 7 and 8 displayed M.S.H. and vasopressinoxytocic activity respectively, with a molecular weight in the region of 5500–6500. Fractions 2 and 5 could not be identified. The fractions seemed to be glycoproteins and the results are discussed in relation to previous findings.     

Phylogeny of the gudgeons (Teleostei: Cyprinidae: Gobioninae)

The members of the cyprinid subfamily Gobioninae, commonly called gudgeons, form one of the most well-established assemblages in the family Cyprinidae. The subfamily is a species-rich group of fishes, these fishes display diverse life histories, appearances, and behavior. The phylogenetic relationships of Gobioninae are examined using sequence data from four loci: cytochrome b, cytochrome c oxidase I, opsin, and recombination activating gene 1. This investigation produced a data matrix of 4114 bp for 162 taxa that was analyzed using parsimony, maximum likelihood, and Bayesian inference methods. The phylogenies our analyses recovered corroborate recent studies on the group. The subfamily Gobioninae is monophyletic and composed of three major lineages. We find evidence for a Hemibarbus-Squalidus group, and the tribes Gobionini and Sarcocheilichthyini, with the Hemibarbus-Squalidus group sister to a clade of Gobionini-Sarcocheilichthyini. The Hemibarbus-Squalidus group includes those two genera; the tribe Sarcocheilichthyini includes Coreius, Coreoleuciscus, Gnathopogon, Gobiocypris, Ladislavia, Paracanthobrama, Pseudorasbora, Pseudopungtungia, Pungtungia, Rhinogobio, and Sarcocheilichthys; the tribe Gobionini includes Abbottina, Biwia, Gobio, Gobiobotia, Huigobio, Microphysogobio, Platysmacheilus, Pseudogobio, Romanogobio, Saurogobio, and Xenophysogobio. The monotypic Acanthogobio is placed into the synonymy of Gobio. We tentatively assign Belligobio to the Hemibarbus-Squalidus group and Mesogobio to Gobionini; Paraleucogobio and Parasqualidus remain incertae sedis. Based on the topologies presented, the evolution of swim bladder specializations, a distinctive feature among cyprinids, has occurred more than once within the subfamily.     

Assessing the true status of the fish species Labeo cylindricus (Peters 1868) (Teleostei: Cyprinidae) in Lake Baringo,Kenya

Eutrophication contributes to the proliferation of alien invasive weed species such as water hyacinth Eichhornia crassipes. Although the South American moth Niphograpta albiguttalis was released in South Africa in 1990 as a biological control agent against water hyacinth, no post-release evaluations have yet been conducted here. The impact of N. albiguttalis on water hyacinth growth was quantified under low-, medium- and high-nutrient concentrations in a greenhouse experiment. Niphograpta albiguttalis was damaging to water hyacinth in all three nutrient treatments, but significant damage in most plant parameters was found only under high-nutrient treatments. However, E. crassipes plants grown in high-nutrient water were healthier, and presumably had higher fitness, than plants not exposed to herbivory at lower-nutrient levels. Niphograpta albiguttalis is likely to be most damaging to water hyacinth in eutrophic water systems, but the damage will not result in acceptable levels of control because of the plant's high productivity under these conditions. Niphograpta albiguttalis is a suitable agent for controlling water hyacinth infestations in eutrophic water systems, but should be used in combination with other biological control agents and included in an integrated management plan also involving herbicidal control and water quality management.     

Phylogenetic analysis of the genus Rasbora (Teleostei: Cyprinidae)

Liao, T. Y., Kullander, S. O. & Fang, F. (2009). Phylogenetic analysis of the genus Rasbora (Teleostei: Cyprinidae).—Zoologica Scripta, 39, 155–176. A phylogenetic analysis was conducted based on 35 cyprinid taxa, including 29 species of Rasbora, and 41 morphological characters. A strict consensus tree from four equally parsimonious trees recovered rasborins as a monophyletic group characterized by (i) presence of dark supra‐anal pigment and subpeduncular streak, (ii) 5–6 branched anal‐fin rays, (iii) dorsal‐fin insertion 1–3 scales behind pelvic‐fin insertion, (iv) lateral process of second vertebra more or less straight, (v) 1–5 more abdominal than caudal vertebrae, (vi) absence of foramen in anterior wall of horizontal limb of the cleithrum, (vii) presence of rasborin process on epibranchial 4, and (viii) interhyal well ossified. Rasbora sensu stricto can be distinguished from all other rasborin genera by the presence of an opercular canal. Four new genera, viz. Brevibora, n. gen., Kottelatia, n, gen., Rasbosoma, n. gen. and Trigonopoma, n. gen., are recognized and described.     

The haematology of Rohu, Labeo rohita

Haematocrit values, haemoglobin concentration, erythrocyte counts, leucocyte counts, erythrocyte sedimentation rate and clotting time of Labeo rohita were determined. The variations in haematological parameters in relation to the size and weight of the fish were also examined. Males had higher haematological values than the females. Seasonal and variations due to maturation of gonads were also apparent.     

Masculinization mechanism of hybrids in bitterlings (Teleostei: Cyprinidae)

The sex ratio of bitterling hybrids (subfamily: Acheilognathinae) is often likely to be biased toward males. Artificial hybridization was carried out in 10 species of bitterlings (three genera) in order to elucidate the masculinization mechanism of hybrids. Tanakia himantegus never produced viable F1 hybrids with other species, while hybrids of most other species were viable. In terms of sex ratio and fertility, hybrids were clearly divided into two groups: congeneric Tanakia hybrids and others. Both male and female congeneric Tanakia hybrids were fertile. The sex ratio was nearly 1:1 in all groups of Tanakia hybrids. Except for the congeneric Tanakia hybrids, sterile males appeared predominantly in groups of hybrids in which females were very rare but remained fertile. Sterile intersexes were also observed in five hybrid groups: T. lanceolata (female) x Acheilognathus cyanostigma (male), Rhodeus uyekii (female) x T. lanceolata (male), A. rhombeus (female) x T. lanceolata (male), A. rhombeus (female) x T. limbata (male), and A. tabira tabira (female) x A. cyanostigma (male). In the development of male-predominant hybrids, although hybrid and control (parental species) hatching and survival rates do not differ, no females appeared in hybrids, contrary to the controls. Taking the female heterogametic sex-determining system (ZW) and the phylogenetic relationship of bitterlings into consideration, the masculinization mechanism of hybrids in bitterlings can be explained by the interaction of two sex chromosomes, derived from each parental species. The basic genetic sex in bitterlings is male (ZZ) and the derivative is female (ZW). When parental species are related, the sex phenotype of hybrids coincides with the genetic sex. However, when the parental species differ, the sex phenotype of the ZW genotype is reversed to become male by an abnormal interaction between the Z and W chromosomes. The rare appearance of females and intersexes in male-predominant hybrids might be due to complete or partial functional expression of the W chromosome.     

Studies on the age and growth of the bata,Labeo bata (Ham.) (Cyprinidae,Teleostei) from the river Kali,India

Age and growth of Labeo bata (Ham.) was studied by the analysis of annuli found on the scale and by length-frequency distribution. The fish attained lengths of 131, 194, 236, 277, 314, 341 and 364 mm at the end of the 1st, 2nd, 3rd, 4th, 5th, 6th and 7th years of life respectively. The increase in length of scale bears a constant relationship with the increase in length of fish, and regression analysis yielded a straight line between scale and body length. Calculated values could be expressed as: Y = –2.534 + 0.064 XThe growth rate of the fish was found high during the 1st and 2nd years and decreased gradually afterwards till the 7th year. Both sexes showed more a or less similar growth rate and attained a similar longevity. Growth trend of the fish confirmed the von Bertalanffy growth equation: Lt = 450(l–e^{–0.2165(t+0.5963))} The seasonal growth curve was chiefly influenced by feeding intensity in fishes of 1st year class while in adults it was affected by feeding intensity as well as by maturation of the gonads.     

Physical characteristics of the blood plasma of Labeo ruddi and Labeo rosae (Pisces: Cyprinidae).

1. The physical composition of blood plasma of Labeo ruddi and Labeo rosae males were determined during the breeding and post breeding phases. 2. The mean values for most blood electrolytes, pH and osmolality of the two species showed the same variation as was found for other cyprinids. 3. The ability to handle stress may be reflected in the presence of certain electrolytes in the blood and efforts are made to relate differences in the concentration of these parameters to interspecies differences between L. ruddi and L. rosae.     

Morphology and fine structure of Barbus barbus (Teleostei: Cyprinidae) spermatozoa

Morphology and fine structure of Barbus barbus L 1758 spermatozoa were studied using scanning (SEM) and transmission (TEM) electron microscopy. The results confirm that spermatozoa exhibit morphological features typical to all teleost fishes. They are differentiated into a head, a midpiece and a flagellum with the typical '9 + 2' pairs of microtubules. Both dynein arms are present in the flagellum. The spermatozoa have spherical nuclei, 4–6 mitochondria located in the postnuclear cytoplasmic region and centriolar complex (proximal and distal centrioles). Total length, head width, length of midpiece and length of flagellum were measured to be 56.35 ± 7.42, 1.80 ± 0.06, 0.48 ± 0.14 and 54.30 ± 6.97 μm, respectively. Highly significant linear correlation was observed between posterior and anterior width of midpiece (P < 0.01). Principal component analysis (PCA) was used to explore which parameters can explain the individual variation of sperm morphology. About 44% of the total accumulated variance was absorbed by the analysis of the two first components, distinguishing different groups of parameters related to head and midpiece. The lengths of flagellum and head are more isolated; indicating that the individual variation of sperm morphology depends on these two parameters. Comparing the results of this study with information on cyprinids spermatozoa reveals that the number of mitochondria and the length of the flagellum are good characters to characterize spermatozoa of the Cyprinidae in a phylogenetic arrangement.     

Molecular Phylogeny and Biogeography of Percocypris (Cyprinidae,Teleostei)

Fierce predatory freshwater fishes, the species of Percocypris (Cyprinidae, Teleostei) inhabit large rivers or lakes, and have a specific distribution pattern. Only a single species or subspecies occurs in each large-scale drainage basin of the Southeastern Tibetan Plateau. In this study, the molecular phylogenetic relationships for all but one of the described subspecies/species of Percocypris were investigated based on three mitochondrial genes (16S; COI; Cyt b) and one nuclear marker (Rag2). The results of Maximum Likelihood and Bayesian Inference analyses show that Percocypris is a strongly supported monophyletic group and that it is the sister group of Schizothorax. Combined with analyses of morphological characters, our results suggest that Percocypris needs to be reclassified, and we propose that six species be recognized, with corresponding distributions in five main drainages (including one lake). In addition, based on the results of the estimation of divergence times and ancestral drainages, we hypothesize that Percocypris likely originated in the early Miocene from a paleo-connected drainage system containing the contemporary main drainages of the Southeastern Tibetan Plateau. This study suggests that vicariance (due to the uplift of the Tibetan Plateau modifying the large-scale morphologies of drainage basins in the Southeastern Tibetan Plateau) has played an important role in the speciation of the genus. Furthermore, external morphological characters (such as the length of the fins) and an internal trait (the position of pterygiophore) appear to be correlated with different habitats in rivers and the lake.     

BarredDanio species from the Irrawaddy River drainage (Teleostei, Cyprinidae)

The three barredDanio species known from the Irrawaddy River drainage are redescribed. Two species are known from southwestern Yunnan:Danio interruptus in the Husa He and Longchuan, Jian watersheds, andD. apogon abundantly in the main river and tributaries of the Daying Jiang basin. The third species,D. shanensis, occurs in the Myitnge basin of northern Shan State, Myanmar.Danio interruptus differs from other barredDanio species by having a short, incomplete lateral line, a deeper head, and shorter thicker dark vertical bars or blotches anteriorly on the sides.Danio shanensis has the lateral line either complete or incomplete, lesser head depth, and a series of deeper narrower vertical bars.Danio apogon has no lateral line, narrow or indistinct dark vertical bars, and a wide, but indistinct, horizonatal P stripe.Danio choprae, previously considered, as a barredDanio species, is more closely related to theD. dangila species group.     

Transparent-Scaled Variant of the Rosy Bitterling, Rhodeus ocellatus ocellatus (Teleostei: Cyprinidae)

Transparent-scaled variant (TSV) of the rosy bitterling Rhodeus ocellatus ocellatus (Kner) was observed on both morphology and heredity. Compared with the normal-scaled type (NST), TSV is characterized by the blackish coloration in both eyes and peritoneum, and the luminescent one over the whole body. Histologically, the density of guanophores containing reflecting platelets was conspicuously low, especially in scale, iris, choroid and peritoneum, while the increase in the number of goblet cells (mucous cells) was recognized all over the dermal/epidermal regions. The heredity of TSV was recessive and supposed to be controlled by a single pair of genes unrelated to sex, judging from the result of crossbreeding experiments between NST and TSV. In growth and reproduction, no difference was seen between these two phenotypes. Transparent-scaled variant of the rosy bitterling can be competent for a genetic marker in experimental and developmental biology.     

Mitochondrial phylogeny and biogeography of the genus Gobio (Teleostei: Cyprinidae) in Turkey

Species of the cyprinid genus Gobio Cuvier, 1816 are widely distributed in freshwater lakes and rivers in Turkey, which is a hotspot for freshwater fish diversity and endemism. The mitochondrial 16S, coxI and cytb genes were sequenced for 217 individuals representing 15 species of Gobio from Turkey. A total of 23 haplotypes were identified for each mitochondrial gene. The genetic distance matrices show that Turkish Gobio species are clustered into three groups (northwestern, central and northeastern Anatolia). Phylogenetic trees constructed with combined dataset by using maximum parsimony, maximum likelihood and Bayesian inference methods revealed that the Turkish Gobio species belongs to three well-supported groups in accordance with their geographic distribution: Group I comprises species found in Central Anatolia, Group II species ranging from eastern Thrace to western Anatolia (northwestern Group) and Group III contains only one species from Western Transcaucasia (northeastern Group). The estimated divergence times between the three Gobio groups, calculated using a conventional 1% rate of mutation for a fish mitochondrial cytb gene per million years, coincide with the late Miocene period in which the tectonic uplift of Anatolia and global climate fluctuations occurred. The relatively low genetic distance between Gobio species in the Turkish Lake District indicate that they are not good species.     

Molecular cytogenetic study of the European bitterling Rhodeus amarus (Teleostei: Cyprinidae: Acheilognathinae)

The European bitterlings (Rhodeus amarus) from the Eastern locations were cytogenetically examined by conventional and molecular techniques. All analyzed individuals presented invariably the same chromosomal constitution of 2n = 48, with 8 metacentrics + 20 submetacentrics + 20 subtelo-acrocentrics and C-banding positive heterochromatin at the pericentromeric regions in most of the chromosomes. Moreover, some of the chromosomes had short arms entirely built with heterochromatin. GC-rich Ag-NORs (nucleolus organizer regions) were located at the short arms of two submetacentric chromosomes, and the length polymorphism of these regions was found. Multiple location of 28S rDNA sequences with fluorescence in situ hybridization signals was observed on the long and/or short arms of three submetacentric chromosomes including NOR regions and short arms of three to five acrocentric chromosomes in the studied fish. 5S rDNA sites were found on the short arms of two subtelocentric chromosomes, and telomeric repeats were localized at the ends of all chromosomes. Provided results have expanded our knowledge concerning genetic characteristics of the European bitterlings that may be profitable in the conservation programs of this endangered species.     

Mitochondrial DNA sequence variations and systematics of the genus Distoechodon (Teleostei: Cyprinidae)

In the present paper, nucleotide sequences (925–929 bases) of the mitochondrial D-loop region and complete cytochrome b gene (1140 bases) were determined and analysed to investigate the systematic status of the genus Distoechodon . CSB1, CSB2, CSB3, CSB-D and ETAS were successfully identified in the D-loop region. The sequence variations among different samples suggest that Distoechodon compressus is a valid species and has its distribution in Taiwan, and that D. tumirostris multispinnis does not seem to be a valid species.