Proposed standard mass equations for European chub Leuciscus cephalus in Italy

Total length (L(T)) and mass measurements of 28,596 specimens of European chub Leuciscus cephalus, collected from a variety of waterways across Italy, were used to compute standard mass (W(s)) equations by both empirical percentile (EmP) and regression line percentile (RLP) methods. The use of the EmP W(s) equation [log(10) W(s) = -4·79 + 2·68log(10) L(T) + 0·10(log(10) L(T))(2)] to compute relative mass (W(r)) of L. cephalus in Italy is suggested, as it was not influenced by length-related bias (L(T) range of application = 70-470 mm).     

Phylogeography and postglacial dispersion of the chub (Leuciscus cephalus) in Europe

A phylogeographic analysis of mitochondrial DNA variation was performed in order to test the hypothesis of a postglacial recolonization of mid- and north-European rivers from a Danubian refuge. Over 345 chub specimens from European rivers covering most of the species' native range were investigated using 600 bp of the cytochrome b gene. Chub in European rivers belong to four highly divergent mitochondrial groups (lineages) differing by mean divergence estimates from 5.2% to 7.89%. These four lineages have a largely allopatric distribution, implying four geographical sets: two Mediterranean, and two north-European sets. This pattern provided strong evidence for: (i) the eradication of this species from most of Europe during maximum ice extent; (ii) its survival in four refugia (Adriatic side of the Balkans, eastern Greece (Aegean Rivers), southern tributaries of the Danube, and periphery of Black and Caspian Seas); (iii) a differential postglacial recolonization of mid- and northern Europe from the last two refugia only; (iv) the occurrence of this recolonization in two steps for the Danubian (western) lineage that entered western Europe (Rhine-Rhone-Loire drainages) during the Riss-Würm interglacial period and survived the last glaciation there before colonizing Garonne, UK and German drainages up to the Elbe during the Holocene; and (v) the occurrence of this recolonization in a single step for the Ponto-Caspian (eastern) lineage that entered the Baltic area as far as the Oder in the Holocene. Both lineages came into contact in the River Elbe without evident mixing.     

Morphological development and growth of chub, Leuciscus cephalus (L.), larvae

This study describes the morphological development and early growth of laboratory-raised chub, Leuciscus cephalus (L. 1758), larvae. Larvae hatched with relatively large yolk sacs, stayed motionless at the tank bottom and exhibited short and sudden bursts from time to time. They were olive in colour and with complete absence of melanophores on the body. Larvae were transparent but showed brownish eye pigment. Intense body pigmentation first appeared on day 4 after hatching. By day 8 the yolk sac was fully absorbed; only 30% of the initial population of larvae successfully established exogenous feeding. Fin rays first appeared on the dorsal and anal fins of larvae around day 12. Growth during the yolk sac stage was initially fast but slowed down with the increasing size of larvae at the time of yolk absorption. The specific growth rate (SGR) of larvae declined with time, although the total observation period was relatively short (12 days). SGR values ranged from 5.18 (day 2) to 2.97 (day 12). Only a negligible egg mortality was observed during the period of early endogenous feeding (between days 1 and 6), and about 45% towards the end of endogenous feeding and immediately after the yolk sac phase (between days 7 and 9). During the exogenous feeding period (between days 10 and 12) deaths were negligible.     

Origin, radiation, dispersion and allopatric hybridization in the chub Leuciscus cephalus

The phylogenetic relationships of 492 chub (Leuciscus cephalus) belonging to 89 populations across the species' range were assessed using 600 base pairs of cytochrome b. Furthermore, nine species belonging to the L. cephalus complex were also analysed (over the whole cytochrome b) in order to test potential allopatric hybridization with L. cephalus sensu stricto (i.e. the chub). Our results show that the chub includes four highly divergent lineages descending from a quick radiation that took place three million years ago. The geographical distribution of these lineages and results of the nested clade analysis indicated that the chub may have originated from Mesopotamia. Chub radiation probably occurred during an important vicariant event such as the isolation of numerous Turkish river systems, a consequence of the uplift of the Anatolian Plateau (formerly covered by a broad inland lake). Dispersion of these lineages arose from the changes in the European hydrographic network and, thus, the chub and endemic species of the L. cephalus complex met by secondary contacts. Our results show several patterns of introgression, from Leuciscus lepidus fully introgressed by chub mitochondrial DNA to Leuciscus borysthenicus where no introgression at all was detected. We assume that these hybridization events might constitute an important evolutionary process for the settlement of the chub in new environments in the Mediterranean area.     

Microridges in Cyprinus carpio scale epidermis

Actin‐based microridges were evaluated in koi scale epidermis in situ. The fingerprint‐patterned microridges covered the dorsal face of superficial layer cells and were overall similar to that described in many fishes. Several other microridge patterns were observed, however, ranging from loose or tightly packed ridges, fragmented ridges, a honeycomb ridge pattern and the presence of actin‐rich puncta. Individual F‐actin‐stained microridges varied greatly in length, from a few to 30 μm or more, with a few single ridges extending the entire perimeter of a cell. Branched microridges, comprised of single ridges that appeared continuous with each other, extended to over 150 μm in some cases. The actin‐binding proteins α‐actinin and cortactin were distributed in a dot‐like pattern along the length of individual ridges, consistent with bundled actin cores described in earlier studies. Antiphosphotyrosine antibody failed to detect this signal transduction‐related amino acid modification in microridges unless tyrosine phosphatases were first inhibited, after which bright phosphotyrosine‐rich dots were detected along the microridges.     

Observations on the growth and production of chub Leuciscus cephalus and dace Leuciscus leuciscus in a small lowland river in southeast England

SUMMARY. The River Eden (Kent, England) holds a mixed coarse fish population in which minnows ( Phoxinus phoxinus ), gudgeon ( Gobio gobio ), chub ( Leuciscus cephalus ) and dace ( Leuciscus leuciscus ) are numerically predominant. Chub and dace provide the major interest to anglers and their growth and production were studied. Observed growth rates of both species were marginally below recorded averages from other British habitats. Back-calculations showed that year-class strength and relative growth rates varied between years. Instantaneous mortality rate Z was 0.147 for chub aged 1–10, 0.438 for chub aged 10 and over, and 0.172 for dace. Exclusive of the 0-group, fish numbers, biomass (wet wt) and production were found to be 0.1305 m^-2, 19.12 gm^-2 and 5.38 gm^-2 year^-1, respectively, for chub and 0.0968 m^-2, 4.33 gm^-2 and 1.69 gm^-2 year^-1 for dace. Smoothing of data produced theoretical production figures of 6.69 gm^-2 year^-1 for chub and 1.15 gm^-2 year^-1 for dace.     

Isolation and characterization of microsatellite loci from chub Leuciscus cephalus (Pisces: Cyprinidae)

Twelve microsatellite markers were isolated from chub Leuciscus cephalus Linné, 1766 (Cyprinidae), a freshwater fish widely distributed in Europe. We assessed the level of genetic diversity for these loci in 24 individuals sampled in the Rhone river watershed. Nine loci were polymorphic, displaying from two to 13 alleles per locus with expected heterozygosity ranging from 0.160 to 0.887. Simultaneous migration of different polymerase chain reaction products was developed for routine analysis of L. cephalus populations.     

鲤鱼cDNA-AFLP技术反应体系的建立

将cDNA扩增片段长度多态性(cDNA-amplified fragment length polymorphism)技术应用在鲤鱼基因的转录表达研究中,本文通过对cDNA-AFLP主要步骤的优化和改进,建立起鲤鱼cDNA-AFLP反应体系.结果表明,采用MseⅠ和 BstYⅠ酶切鲤鱼cDNA 100 ng,分别处理2 h和3 h后,以接头浓度分别为2 pmol/μL和0.2 pmol/μL、T4连接酶浓度为0.12 U/μL的反应体系进行连接.以稀释50倍的预扩增产物为模板、BstYⅠ和MseⅠ比例为1:4的引物配比进行选择扩增可得到稳定的扩增结果.本研究建立的cDNA-AFLP技术将为鲤鱼转录组研究建立基础和技术支持.     

Effects of handling and electrofishing on plasma glucose and whole blood lactate of Leuciscus cephalus

Chub Leuciscus cephalus exposed to simulated pulsed direct current electrofishing operations exhibited rapid elevations in plasma glucose and blood lactate levels. Plasma glucose levels were significantly higher 0·5 h after simulated electrofishing operations, and peaked 2 h after treatment. Glucose levels remained high for up to 4 h. No changes in plasma glucose were evident following handling. Simulated electrofishing operations and handling induced an immediate lactacidosis in chub. Initial responses to both treatments were similar except that blood lactate was significantly higher in fish exposed to simulated electrofishing operations than in handled fish 5 and 15 min after treatment. Blood lactate remained elevated in fish exposed to simulated electrofishing operations for 2 h, while blood lactate of handled fish returned to levels similar to those in the control fish within 0·5 h post‐treatment.     

Genetic differentiation among Greek lake populations of Carassius gibelio and Cyprinus carpio carpio

The genetic structure of the Western Greece lake populations of Carassius gibelio and Cyprinus carpio carpio populations was characterized by using a PCR-based RFLP and sequencing analysis of mitochondrial rDNA genes and regions (16S rDNA, cytochrome b and D-loop). Our analysis was able to detect: (a) two haplotypes in C. c. carpio populations and two haplotypes in C. gibelio populations (b) a high nucleotide divergence between the two species and (c) two genetically distinct C. gibelio populations, one existing in the Amvrakia habitat (AMV1) with a second in Ozeros and Trichonida (OZE1 and TRI1) habitat. The present analysis indicates that genetic diversity observed was limited with a haplotype index between 0.0 and 55.6%, and a nucleotide diversity within and among populations between 0.0 and 1.27%. It also underlines a restricted mtDNA-based evaluation of the phylogenetic relationships among C. gibelio and C. c. carpio populations. In addition, the present study contributed knowledge on the genetic variation and structure of these populations which is absolutely necessary for any efficient fish management and/or conservation programme.     

Genetic divergence between Cyprinus carpio carpio and Cyprinus carpio haematopterus as assessed by mitochondrial DNA analysis,with emphasis on origin of European domestic carp

Although common carp is the major fish species in Asian and European aquaculture and many domestic varieties have occurred, there is a controversy about the origination of European domestic common carp. Some scientists affirmed that the ancestor of European domestic common carp was Danube River wild common carp, but others considered it might be Asian common carp. For elucidating origination of European domestic common carp, we chose two representative European domestic common carp strains (German mirror carp and Russian scattered scaled mirror carp) and one wild common carp strain of Cyprinus carpio carpio subspecies (Volga River wild common carp) and two Asian common carp strains, the Yangtze River wild common carp (Cyprinus carpio haematopterus) and traditionally domestic Xingguo red common carp, as experimental materials. ND5–ND6 and D-loop segments of mitochondrial DNA were amplified by polymerase chain reaction and analyzed through restriction fragment length polymorphism (RFLP) and sequencing respectively. The results revealed that HaeIII and DdeI digestion patterns of ND5–ND6 segment and sequences of control region were different between European subspecies C. carpio carpio and Asian subspecies C. carpio haematopterus. Phylogenetic analysis showed that German mirror carp and Russian scattered scaled mirror carp belonged to two subspecies, C. carpio carpio and C. carpio haematopterus, respectively. Therefore, there were different ancestors for domestic carp in Europe: German mirror carp was domesticated from European subspecies C. carpio carpio and Russian scattered scaled mirror carp originated from Asian subspecies C. carpio haematopterus.     

Variability in the growth rate of chub Leuciscus cephalus along a longitudinal river gradient

An increase in individual growth rate of chub Leuciscus cephalus along a longitudinal river gradient of the Rhône River basin was observed and supported by significant differences between mean growth rates of successive river size groups. The potential implications of the results for studies on species traits variability along large-scale environmental gradients are discussed.     

Hybrids of chub and roach (Leuciscus cephalus and Rutilus rutilus) in English rivers

The occurrence of hybrids between chub, Leuciscus cephalus , and roach, Rutilus rutilus , from three rivers in England is reported. The hybrids are described and illustrated, and means of identification are indicated. Chub X roach hybrids, like those between other leuciscine cyprinid species, can be positively identified by the number and form of the pharyngeal teeth.     

Long term Gyrodactylus lomi infection on isolated juvenile chub (Leuciscus cephalus)

Previous studies on long term gyrodactylid infections on isolated fish have shown that for the majority of Gyrodactylus-fish interactions, infections peak at a maximum level and then decline as the host mounts an effective immune response. In the current study, juvenile chub collected from the wild still harboured Gyrodactylus lomi infections after 6 - 10 months in the laboratory despite being individually maintained at 12 C.     

Helminths in Leuciscus cephalus from the river Adda, Lombardy, Northern Italy

Chubs (Leuciscus cephalus) were caught at various locations along the river Adda and from Lake of Como (Lombardy, Northern Italy) and endoparasitic helminths were studied in order to integrate the knowledge on distribution of helminth fauna of chubs in Lombardy and to investigate on the structure of its parasite infracommunities with respect to different habitat typologies. The following species of parasites were isolated: Pomphorynchus laevis, Allocreadium markewitschi, Parasymphylodora markewitschi, Raphidascaris acus, Hysterothylacium aduncum and Molnaria intestinalis. P laevis resulted the most common species (P = 56.52%). The mean abundances and the prevalence of helminths were different in chubs according to the sampling site. The mean abundances were lower in chubs sampled in the lake than those sampled in the river. Particularly, P. laevis showed the highest prevalences in fish captured in the river sites. The trematodes (P. markewitschi and A. markewitschi) seem to be more related with "lake" typology. These results are discussed and related to differences in life cycle of these parasites and to other factors like sampling period and the conditions of the aquatic sites that could influence the richness of parasite species.     

Hybrids of bleak, Alburnus alburnus, and chub, Leuciscus cephalus in English rivers

The occurrence of hybrids between bleak, Alburnus alburnus , and chub, Leuciscus cephalus is reported from four discrete river systems in England. The hybrids are described and illustrated, and means of identification from the parent species are given. Bleak × chub hybrids appear to be moderately common and on superficial examination resemble the bleak parent species more than the chub.