Batch fecundity and spawning frequency of invasive Hemiculter leucisculus (Basilewsky, 1855) in Erhai Lake,China

Hemiculter leucisculus are multiple spawners with indeterminate fecundity, although previous fecundity estimates have assumed a determinate spawning pattern. Batch fecundity and spawning frequency of H. leucisculus were studied in Erhai Lake, China, in which the fish, as an exotic species, has become a successful colonizer. Spawning frequency was 16.05 %, as determined from the percent of females with postovulatory follicles 12 to 36 h old during the peak reproductive period (from May 27 to August 8). The average interval between spawning was 6.2 days and there were more than 16 total spawning batches during the peak reproductive period. The average batch fecundity (mean ± SD) was 11,934?±?5,921 hydrated oocytes in 40 females (standard length or SL: 9.1–14.4 cm), while relative batch fecundity was 560?±?137 eggs g^?1 wet weight. The total potential annual fecundity was approximately 190,944 oocytes over the whole spawning season and was much higher than the estimated standing stock (31,585 oocytes) of yolked oocytes (36 females, SL: 9.5–16.2 cm) at the beginning of the spawning season in April 2010. This high annual fecundity is likely to have contributed to successful invasion of Erhai Lake by H. leucisculus.     

Reproductive strategy of the invasive sharpbelly,Hemiculter leucisculus (Basilewsky 1855), in Erhai Lake,China

This study describes the reproductive strategy of the sharpbelly Hemiculter leucisculus, an invasive and dominant species in Erhai Lake in China with the goal of understanding how reproductive strategy contributes to its environmental adaptability and invasive potential. Specimens (n = 3583) were collected monthly or bimonthly from July 2009 to June 2011 (min: 114‐Feb, max: 883‐Aug), using gill nets (inner/outer mesh = 30/110 mm, stretched mesh). Gonads were removed, weighed and preserved for further (histological) analyses. Oocyte size‐frequency distribution was continuous and had advanced vitellogenic oocytes with postovulatory follicles present in spawning females, both suggesting that sharpbelly is a multiple spawner with adhesive eggs. Spawning extended from April to September, with the peak period from May to August. Standard lengths (SL, cm) at minimal observed maturity/L₅₀/L_99.9 values were 4.6/5.6/10.5 for females and 5.1/5.5/7.5 cm for males, respectively. Females were over‐represented (P < 0.01) in SL‐classes over 9 cm and males completely absent from the 13 to 19 cm SL‐classes. Overall sex ratio was highly significantly (P < 0.01) biased towards females (♀ = 1518, ♂ = 685, ♀/♂  = 2.21), however this was reversed in the spawning stock (8.3–16 cm, ♀ = 58, ♂ = 142, ♂/♀  = 2.45, P < 0.01). Batch spawning, a long spawning period, high male investment in reproduction and adhesive eggs all represent local adaptations in reproductive strategy that, along with other environmental factors, contribute to the invasion success of sharpbelly in Erhai.     

Age,growth and mortality of invasive sharpbelly,Hemiculter leucisculus (Basilewski, 1855) in Erhai Lake,China

The sharpbelly Hemiculter leucisculus, an invasive species, has expanded its range throughout much of Asia and into the Middle East. However, little is known of its adaptive changes regarding life history traits such as age, growth and mortality that could possibly explain its success as an invasive species. A detailed study of the invasive sharpbelly was conducted based on 4539 samples collected from July 2009 to June 2011 in Erhai Lake, China. Standard length ranged from 4.3–19.1 cm for females and 4.6–12.3 cm for males. Length–weight relationships for females and males were significantly different and described as W = 0.0076SL^3.2608 and W = 0.0084SL^3.1901, respectively. Otoliths are ideal for age determination because of the single annulus formed each year. Based on marginal increment analysis, the total mean CV for age estimate between two readings was 3.55%. The von Bertalanffy growth curves computed by observed length‐at‐age data were expressed as L_t = 25.6 (1 ? e^{?0.176 (t + 1.347)}) for females and L_t = 16.4 (1 ? e^{?0.354 (t + 0.819)}) for males. According to the age, growth and mortality data, there are three possible reasons for H. leucisculus attaining such dominance within a short time in Erhai Lake. First, because of the simple age structure of this species: 97.58% of males were 1–2 years old with a maximum age of only 3 years; 93.14% of females were 1–3 years old, with a maximum age of 6 years. Second, females grew larger than males at any age. Third, instantaneous mortality rates were much higher for males (4.22 year^?1) than for females (1.17 year^?1).     

Population genetic structure of sharpbelly Hemiculter leucisculus (Basilesky, 1855) and morphological diversification along climate gradients in China

Sharpbelly Hemiculter leucisculus (Basilewski, 1855) is a small, widespread, and native cyprinid fish with prominent habitat suitability and high invasive potential and is becoming the dominant species in freshwater ecosystems under intensified environmental disturbances. But how H. leucisculus acclimates to extremely heterogeneous environments remains unclear. In current study, the genetic structure of H. leucisculus was analyzed using Bayesian phylogenetic inference, haplotype network, and STRUCTURE base on cytb gene across 18 populations spanning 20 degrees of latitude and 18 degrees of longitude in China. The morphological diversification of body size and shape for H. leucisculus along the climate gradient was studied. The results showed that the 18 H. leucisculus populations were divided into 3 clusters: one cluster mainly from Huanghe River Basin, another cluster mainly from Yangzi River Basin, and H cluster containing Hainan and Beihai populations. The fish from southern populations were deeper bodied while individuals from northern populations were more slender. Inland individuals were more streamlined while coastal individuals were of deeper body. The partial Mantel test predicts that the potential mechanism underlining the intraspecies morphological diversification along climate gradients is primarily the divergent selection pressures among different environments, while genetic variation had less contribution to morphological differentiation. The formation of the Nanling Mountain Range could drive genetic differentiation between Beihai population and those from Yangzi River Basin. The present results highlight strong selective pressures of climate on widespread species and enrich morphological differentiation basis of acclimation for species with high habitat suitability and invasive potential.     

Reduced growth and reproductive investment of Hemiculter leucisculus (Cyprinidae) in a reservoir with introduced icefish Neosalanx taihuensis (Salangidae)

Neosalanx taihuensis is an important zooplanktivorous commercial fish that has been widely introduced into Chinese freshwaters. Introduction of this species has induced decline and even extinction of native fish species in some waters. In this study, impacts of N. taihuensis introduction on growth and reproductive characteristics of an indigenous zooplanktivorous fish Hemiculter leucisculus were investigated by comparing population traits of the latter species in two reservoirs that differ only in whether N. taihuensis has been introduced. Huangshi Reservoir (HSR) and Mengquan Reservoir (MQR) are geographically proximate and display similar nutrient regimes and native fish faunas, but N. taihuensis has been stocked only in HSR. Populations of H. leucisculus in both reservoirs consisted of three age groups, ranging from age 1 to 3. Standard length (SL), body weight and back-calculated SL-at-age of H. leucisculus in HSR were significantly less than in MQR for both males and females in each age group. Female H. leucisculus also tended to produce fewer and smaller eggs (indicated by lower absolute fecundity, gonad weight and smaller egg diameter) in HSR than in MQR for each age group. We suggest that reduced growth and reproductive investment by H. leucisculus in HSR are likely the result of N. taihuensis introduction.     

澜沧江鳘条寄生指环虫属两新种记述

本文记述了云南澜沧江水系景洪流域段(100°47'43″E,22°0'28″N)鳘条Hemiculter leucisculus(Basilewsky,1855)鳃丝上寄生指环虫属Dactylogyrus 2新种,以采集地命名为版纳指环虫Dactylogyrus bannaensis sp.nov.和景洪指环虫D.jinghongensis sp.nov.。版纳指环虫和景洪指环虫均为双联结片虫,基于后吸器,尤其是中央大钩、边缘小钩和交接器的形态学特征,鉴定为指环虫属科学上2新种。版纳指环虫交接器的形态有别于记录种船茎指环虫D.nilkolskyi Gussev,1955,版纳指环虫的交接管呈长带状,延伸至虫体左侧边缘阴道口处,末端微弯;感染率100%(40/40)。寄生于同一宿主的景洪指环虫,其交接器的形态有别于记录种红鲌指环虫D.erythroculteris和锥花指环虫D.pannosus,景洪指环虫的交接器呈彩虹状,交接管的一端基部膨大成漏斗状,另一端折叠;支持器"V"形,且中间包绕交接管;感染率100%(40/40)。     

Phylogenetic Relationships and Taxonomy of the Carp Fish of Genus Hemiculter (Cyprinidae,Xenocypridinae): Species of the Group H. leucisculus

Journal of Ichthyology - The three differentiated phylogenetic lineages of sharpbelly from the group Hemiculter leucisculus s.l. corresponding to clades A, B, C sensu Chen et al. (2017) have been...     

Taxonomy and Phylogenetic Relationships of Cyprinid Fish of Genus Hemiculter (Cyprinidae,Xenocypridinae): Sharpbellies of the Species Group Hemiculter lucidus

Journal of Ichthyology - On the basis of a comparative morphological analysis, the multi-rakered sharpbellies were divided into four groups, differing in the number of branched rays in the anal...     

Isolation and charaterization of polymorphic microsatellite loci from so-iuy mullet (Mugil soiuy Basilewsky 1855)

The first set of polymorphic microsatellite markers were developed from so-iuy mullet (Mugil soiuy Basilewsky 1855). From a (GT)n-enriched genomic library, 53 microsatellites were selected for designing microsatellite primers, of which 36 gave working primer pairs. Ten of these loci were polymorphic in a test population of 24 individuals with alleles ranging from 3 to 9, and observed and expected heterozygosities from 0.2083 to 0.9167 and from 0.2651 to 0.8812, respectively. No significant linkage disequilibrium between pairs of loci was found, but two loci significantly deviated from Hardy–Weinberg equilibrium after Bonferroni correction. These polymorphic microsatellite loci should provide sufficient level of genetic diversity to investigate the fine-scale population structure and evaluate the breeding strategy in Mullet. Genbo Xu and Changwei Shao Contributed equally.     

Comparative osteology of lotaks, Cyprinion kais and C. macrostomum (Cypriniformes, Cyprinidae), from Godarkhosh River, western Iran

Osteology of two cyprinid fishes, Cyprinion kais and C. macrostomum, from the Tigris-Euphrates basin was described and compared. Eight specimens of C. kais and ten specimens of C. macrostomum from Godarkhosh River (western Iran) were studied. The skeletal elements were prepared using clearing and softening methods and photographed. The differences between the two taxa include a deeper posterior position of the lower jaw with a much narrower labial surface, a longer last dorsal unbranched ray with weaker posterior serration, and a more embowed dentary, maxillary and premaxillary in C. kais. Based on these differences, the examined specimens of these two taxa could be easily distinguished.     

Range extension of Brathinus satoi in China (Coleoptera,Staphylinidae)

Brathinus satoi Kishimoto & Shimada, 2003 is recorded from Longwangshan Nature Reserve, Zhejiang, China. Some diagnostic characters of the species are discussed based on more specimens, and some biological notes are made on the species.     

Fatty acid profiles of the topmouth culter (Culter alburnus Basilewsky, 1855) from five lakes located at different latitudes in China

The topmouth culter (Culter alburnus Basilewsky, 1855) is a freshwater carnivorous fish of high nutritional value and widely distributed in lakes and reservoirs of China. In order to evaluate the fatty acid profiles in relation to habitat characteristics and to elucidate the main composition predictors, C. alburnus were collected from five lakes (Xingkai‐ LXk, Hongze‐ LHz, Kuilei‐ LKl, Chidong‐ LCd and Dongting‐ LDt) in China, ranging in latitudes from 28°30′ to 44°44′N and altitudes from 4 to 64 m. Ten fish from each lake ranging in total lengths from 414.2 to 423.9 mm were sampled between May to June in 2013 and 2014. A total of 23 fatty acids were identified using gas chromatography. Fatty acids that predominated in muscle samples of the fish were 16:0, 18:0, 16:1n?7, 18:1n?9, 20:5n?3, 22:6n?3 and 20:4n?6. Important differences in the fatty acid profiles of fish from high and low latitude lakes were discernible in that the two high latitudinal lakes (LXk and LHz) had significantly higher (p < .05) ratios of n?3 to n?6 fatty acids and levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), than those fishes in the low latitudinal lakes (LKl, LCd and LDt); these observations were confirmed by a principal component analysis. Therefore, it appears that multivariate analysis enables to distinguish fish from different lakes based on their characteristic fatty acid signatures; this would make a contribution to fish product traceability. The percentages of total saturated fatty acids increased significantly with increasing ambient temperature, and lakes at lower latitudes had higher levels of 17:0, 18:0, 18:2n?6, 20:3n?6 and lower levels of 16:1n?7 and 18:1n?9. Theoretical information criteria showed that the percentage of total saturated fatty acids varied more with temperature than with latitude and that this temperature‐dependent variation is nonlinear. Variation partitioning shows that most of the geographical variations are not only due to the nonlinear effects of temperature but also to the independent effects of the lake features. By contrast, no significant variations in fish lengths were found.     

A faunistic study on the leafhoppers of northwestern Iran (Hemiptera,Cicadellidae)

The leafhopper fauna of northwestern Iran: Azarbaijan-e-Sharghi, Azarbaijan-e-Gharbi and Ardabil provinces is listed from previously published records and from our current work. Sixty-nine species are included with four species (Mogangella straminea Dlabola, 1957, Doratura stylata (Boheman, 1847), Macrosteles sordidipennis (Stål, 1858) and Psammotettix seriphidii Emeljanov, 1962) listed as new for Iran and Balclutha punctata (Fabricius, 1775), as a new record for the region. A distribution map of the species in northwestern Iran is given.     

Intestinal protozoa in wild boars (Sus scrofa) in western Iran

A total of 12 gastrointestinal tracts of wild boars (Sus scrofa) from western Iran (Luristan) were examined for protozoan infection between September 2000 and November 2001. Of 12 boars examined, 67% harbored one or more species of the following protozoa: Balantidium coli (25%), Tritrichomonas suis (25%), Blastocystis sp. (25%), Entamoeba polecki (17%), Entamoeba suis (8%), Iodamoeba butschlii (17%), and Chilomastix mesnili (8%). Four of these protozoan species also are reported in humans, and persons living in rural areas where wild boars are abundant should take precaution to avoid infection.     

Sexual size dimorphism in Darevskia raddei (Sauria: Lacertidae) from northwestern Iran

We examined sexual size dimorphism of the rock-dwelling lizard Darevskia raddei (Boettger, 1892) with the help of 30 specimens that were provided from various sources. Eleven metric and seven meristic features were examined. Seven characters (gulars, length of basal tail, femoral pores, length of head, width of head, length of fore limb and length of hind limb) were identified as dimorphic between the two sexes. Some of these characters have important roles in copulation for males, especially the hind limb and the tail base. The number of femoral pores is important in the release of signal components because females release these components to attract males during the mating season. The length of the hind limb as locomotor performance plays an important role during mating, so that the male can grasp the female and adopt the correct position during copulation.