Age, growth and reproduction of the cyprinid Rutilus lemmingii (Steindachner, 1866) in the River Huebra, Central Spain

Age, growth and reproduction of the R. lemmingii population of the River Huebra, Duero basin are analysed. Females dominated older age classes and lived up to 6 years (5+) while males only reached 5 years (4+). The growing season extended from April to September; growth rates were similar for both sexes. 0+ fish condition increased during their first summer and spring. In older fish, condition cycle was related to gonad development and showed some differences between sexes. The number of females reaching maturity at age 1 + almost doubled that of males; females also matured at smaller size. Both fecundity and egg size increased with female length: mean egg counts varied between 974 for 1 + individuals and an estimated 10491 for 5+ fish. Eggs were produced as a single batch, but were released fractionally during April and May.     

Performance of fish lift recently built at the Touvedo Dam on the Lima River, Portugal

From March 1998 to February 1999, upstream fish passage was continuously monitored by video tape analysis at the fish lift Touvedo Dam on the Lima River, northern Portugal. A total of 1194 individuals from seven species were transferred by the lift. Cyprinids were the dominant group collected, with Iberian nase Chondrostoma polylepis (Steindachner) (31.8%) being the most abundant species, followed by Iberian barbel Barbus bocagei (Steindachner) (21.1%), Iberian dace Leuciscus carolitertii (Doadrio) (19.2%) and Iberian red roach Rutilus arcasii (Steindachner) (7.1%). Brown trout Salmo trutta fario (L.) and European eel Anguilla anguilla (L.) accounted for 10.8%, whereas Atlantic salmon Salmo salar (L.) was rarely observed. Most cyprinid seasonal movements were observed in the spring and were associated with reproduction. The timing of the run varied and its beginning appeared to be mainly dependent on water temperature. Roach, dace and nase used the fish lift intensively from mid-April until the end of summer. Barbel use of the lift intensified in mid-May in association with warmer water. Salmonids migrated in June–July and autumn. Significant differences were not found in hourly activity, except for nase and barbel, in June and July, respectively. Fish passage was not related to river discharge. The relative effectiveness of the fish lift is discussed in relation to the various species.     

Biometrical analysis of Chondrostoma polylepis × Rutilus arcasi natural hybrids (Osteichthyes—Cypriniformes—Cyprinidae)

The biometrical analysis of 95 natural hybrids of Chondrostoma polylepis and Rutilus arcasi is presented and discussed. The authors confirmed their existence in the Douro basin and, based on these data, they try to explain their non-accidental character. The possibility of introgression, and other aspects of hybridization are analysed in an attempt to explain the variability observed.     

Population genetic structure in the Iberian cyprinid fish Iberochondrostoma lemmingii (Steindachner, 1866): disentangling species fragmentation and colonization processes

Interplay between the complex geography, hydrogeomorphological history, past climatic changes, and anthropogenic pressures is likely responsible for the current diversity and species' distribution of freshwater fishes in the Iberian Peninsula. To further disentangle the evolutionary processes promoting the diversification of endemic Iberian Cyprinids through time and space, we explored the patterns of genetic diversity of the Iberian arched‐mouth nase, Iberochondrostoma lemmingii (Steindachner, 1866), using molecular markers rendering at different timescales: the mitochondrial gene cytochrome b and seven microsatellite loci. Both markers showed significant differentiation of populations though the relative genetic distances among populations were different between markers. Mitochondrial DNA results indicate the isolation of hydrographic basins as the main driver of population differentiation, with Tejo as the centre of diversification. The results also support connections between Tejo, Guadiana, and Guadalquivir, with levels of divergence suggesting an earlier severance of Guadalquivir, whereas Guadiana and Tejo maintained connections until a more recent past. Establishment of more peripherial populations in small southern basins (Quarteira and Almargem) could have been ruled by founder events. However, the analysis of present‐day genetic configuration suggested by microsatellite data implies, for the first time, the involvement of other factors in the evolution of arched‐mouth Iberian nase populations. Relative low genetic distances between inter‐basin populations (Tejo and Guadiana) and the lack of concordance between differentiation and geography suggest a possible influence of human‐mediated translocations in the population genetic patterns of I. lemmingii. High intra‐basin differentiation levels were found within Tejo and Guadiana and may be associated with factors intrinsic to the species (e.g. low dispersal capability) or natural and/or artificial barriers to gene flow. The low vagility of the species appears to be an important factor influencing the evolutionary processes shaping the phylogeographical patterns of I. lemmingii, which could be relevant for the conservation of this threatened species. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 559–572.     

The first record of a natural hybrid of the roach Rutilus rutilus and nase Chondrostoma nasus in the Danube River Basin, Czech Republic: morphological, karyological and molecular characteristics

Morphological (meristic and morphometric traits), karyological and molecular (microsatellites, cytochrome b ) analyses were performed to characterize a hybrid of the roach Rutilus rutilus and nase Chondrostoma nasus . Meristic and morphometric traits were different between hybrid and both parental species. The number of chromosomes found in hybrid specimen indicated that this individual represents the post-F₁ generation of hybrids and the microsatellite analysis of the hybrid showed the presence of variants typical for R. rutilus and C. nasus .     

Influence of Environment and Mitochondrial Heritage on the Ecological Characteristics of Fish in a Hybrid Zone

Background

Ecological characteristics (growth, morphology, reproduction) arise from the interaction between environmental factors and genetics. Genetic analysis of individuals'' life history traits might be used to improve our understanding of mechanisms that form and maintain a hybrid zone.

Methodology/Principal Findings

A fish hybrid zone was used to characterize the process of natural selection. Data were collected during two reproductive periods (2001 and 2002) and 1117 individuals (nase, Chondrostama nasus nasus, sofie C. toxostoma toxostoma and hybrids) were sampled. Reproductive dates of the two parental species overlapped at sympatric sites. The nase had an earlier reproductive period than the sofie; males had longer reproductive periods for both species. Hybridisation between female nase and male sofie was the most likely. Hybrids had a reproductive period similar to the inherited parental mitochondrial type. Growth and reproductive information from different environments has been synthesised following a bayesian approach of the von Bertalanffy model. Hybrid life history traits appear to link with maternal heritage. Hybrid size from the age of two and size at first maturity appeared to be closer to the size of the maternal origin species (nase or sofie).Median growth rates for hybrids were similar and intermediate between those of the parental species. We observed variable life history traits for hybrids and pure forms in the different parts of the hybrid zone. Geometrical analysis of the hybrid fish shape gave evidence of two main morphologies with a link to maternal heritage.

Conclusions/Significance

Selective mating seemed to be the underlying process which, with mitochondrial heritage, could explain the evolution of the studied hybrid zone. More generally, we showed the importance of studies on hybrid zones and specifically the study of individuals'' ecological characteristics, to improve our understanding of speciation.     

Gametophyte morphogenesis of Mexican species of Pleopeltis (Polypodiaceae, subfamily Pleopeltoideae)

The development and morphology of the gametophytes of seven species of ferns from genus Pleopeltis are described and compared. The spore germination is Vittaria-type in P. astrolepis, P. crassinervata, P. macrocarpa, P. polylepis and P. revoluta. For P. angusta and P. mexicana it was proposed a new germination pattern is Pleopeltis-type. The prothallial development is Drynaria-type in P. astrolepis, P. crassinervata, P. macrocarpa, P. polylepis and P. revoluta and Ceratopteris-type for P. angusta and P. mexicana. The gametangia are typical of the leptosporangiate ferns, sporophytes after six and a half months in culture did not appeared.     

The Hemiuroidea (Digenea) of pomacentrid fishes (Perciformes) from Heron Island,Queensland, Australia

The following species are described, figured and/or recorded from pomacentrid fishes from the vicinity of the southern Great Barrier Reef coral cay Heron Island, with some mention of comparative material from other host families and locations: Derogenes pearsoni n. sp. from Amblyglyphidodon curacao, Amphiprion akindynos, Plectroglyphidodon lacrymatus (type-host), Pomacentrus chrysurus, P. moluccensis, P. tripunctatus and Pomacentrus sp.; Derogenes pharyngicola n. sp. from Abudefduf whitleyi (type-host) and Plectroglyphidodon dickii; Lecithaster stellatus from Abudefduf sexfasciatus, A. whitleyi, Acanthochromis polyacanthus, Amblyglyphidodon curacao, Chrysiptera flavipinnis, Parma polylepis, Pomacentrus chrysurus, P. moluccensis, P. cf. nagasakiensis, P. cf. pavo, P. vaiuli, P. wardi, Seriola lalandi, Cheilinus diagrammus, Lethrinus miniatus and Choerodon cyanodus from Heron Island plus Acanthopagrus australis and Rhabdosargus sarba from Moreton Bay; Aponurus laguncula from Pomacentrus moluccensis plus Callionymus limiceps, Platycephalus endrachtensis and P. fuscus from Moreton Bay; Hysterolecitha nahaensis from Abudefduf bengalensis, A. sexfasciatus, A. whitleyi, Acanthochromis polyacanthus, Amblyglyphidodon curacao, A. leucogaster, Amphiprion akindynos, A. perideraion, Chromis atripectoralis, C. nitida, C. viridis, Chrysiptera flavipinnis, C. cf. rollandi, Dascyllus aruanus, D. reticulatus, Parma polylepis, Pomacentrus chrysurus, P. moluccensis, P. cf. nagasakiensis, P. nigromarginatus, P. cf. pavo, P. tripunctatus, P. wardi and Pomacentrus sp.; Hysterolecitha heronensis n. sp. from Pomacentrus philippinus (type-host), P. amboinensis, P. moluccensis, P. nigromarginatus and Pomacentrus sp.; Hysterolecitha sp. innom. from Parma polylepis; Thulinia microrchis n. comb. (new syns Hysterolecitha microrchis, H. xesuri, H. tinkeri, Thulinia tinkeri, H. sigani) from Abudefduf bengalensis, A. sexfasciatus, A. whitleyi, Acanthochromis polyacanthus, Amphiprion perideraion, Dascyllus aruanus, D. reticulatus, Dischistodus melanotus, Parma polylepis, Plectroglyphidodon dickii, Pomacentrus amboinensis, P. moluccensis, P. philippinus, P. taeniometopon, Pomacentrus sp. and Stegastes apicalis, plus Chaetodon citrinellus, C. kleinii, Chaetodontoplus meredithi, Lethrinus miniatus, Plectropomus leopardus, Siganus doliatus, S. lineatus and S. vulpinus; Leclthocladium sp. juv from Abudefduf whitleyi, Lecithochirium sp. (? ghanense-group) from Dascyllus aruanus; Lecithochirium sp. juv. from Abudefduf whitleyi; unidentified non-ecsomate hemiuroids from Chrysiptera cf. rollandi, Parma polylepis, Pomacentrus chrysurus, P. wardi and Stegastes apicalis.     

The amino acid sequence of protein CM-3 from Dendroaspis polylepis polylepis (black mamba) venom

Protein CM-3 from Dendroaspis polylepis polylepis venom was purified by gel filtration and ion exchange chromatography. It comprises 65 amino acids including eight half-cystines. The complete amino acid sequence of protein CM-3 has been elucidated. The sequence (residues 1-50) resembles that of the N-terminal sequence of the subunits of a synergistic type protein and residues 51-65 that of the C-terminal sequence of an angusticeps type protein. Mixtures of protein CM-3 and angusticeps type proteins showed no apparent synergistic effect, in that their toxicity in combination was no greater than the sum of their individual toxicities.     

Occurrence of Hemitaurichthys polylepis in the Coastal Waters of Southern Central Vietnam (South China Sea)

Journal of Ichthyology - The photographs of Hemitaurichthys polylepis in the natural environment of the coastal waters of Vietnam (Hon Noi) are given for the first time. The feeding of the...     

Swimming performance of two Iberian cyprinids: the Tagus nase Pseudochondrostoma polylepis (Steindachner, 1864) and the bordallo Squalius carolitertii (Doadrio, 1988)

The main purpose of this study was to gather swimming performance information for two endemic cyprinids of the Iberian Peninsula to contribute to the optimization of fish ways. Critical swimming speed (U_crit) was determined for the Tagus nase Pseudochondrostoma polylepis (Steindachner, 1864) and for the bordallo Squalius carolitertii (Doadrio, 1988) in a swimming tunnel. From a total of 80 P. polylepis tested, the mean (± SD) U_crit observed was 0.78 ± 0.15 ms^?1 (c. 3.74 ± 0.93 BL s^?1); the 68 S. carolitertii tested presented an U_crit of 0.54 ± 0.1 ms^?1 (c. 4.43 ± 0.74 BL s^?1). Significant interspecific differences were found between the U_crit of the tested cyprinids. Intraspecific comparisons between the U_crit and the variables of size, sex, condition factor and gonado‐somatic index were also made. No sex‐or gonad maturation‐related differences between the U_crit were identified, but the robust P. polylepis were found to be stronger swimmers. Water velocities in fish ways for P. polylepis and S. carolitertii should aim, on average, for lower than 0.7 and 0.5 ms^?1, respectively.     

A simple and highly efficient fixation method for Chrysochromulina polylepis (Prymnesiophytes) for analytical flow cytometry

BACKGROUND: To study the fragile Prymnesiophyte species Chrysochromulina polylepis by flow cytometry (FC), we needed an effective fixation method. This method must guarantee a high yield of fixed cells to achieve acceptable measurement times by FC and to allow quick processing of many samples. Moreover, we wanted a method that allows for storage of fixed samples when FC analysis cannot be done immediately. METHODS: Different aldehydes and methanol were tested at different final concentrations. Gravity sedimentation and centrifugation were applied to achieve higher cell concentrations. Storage of fixed samples was tested under different conditions. RESULTS: 0.25% glutaraldehyde (GA) fixation yielded a recovery rate of about 90%. The signals obtained by FC analysis were excellent. It is possible to centrifuge GA-fixed cells and to store them for several weeks. CONCLUSIONS: GA is the fixative of choice for FC analysis of C. polylepis (and possibly other small delicate species) because it yielded highly significant recovery rates and high-quality FC signals. Cells can be centrifuged to increase the cell concentration, thereby achieving short measurement times with FC. The possibility of long-term storage of fixed cells presents an additional advantage if FC analysis cannot be done immediately.     

The age, growth and reproduction of Chondrostoma polylepis willkommi in a seasonal stream in the Guadalquivir River basin (southern Spain)

The age, growth and reproduction of Chondrostoma polylepis willkommi , an endemic cyprinid from the Iberian Peninsula, was studied for 2 years in a seasonal stream in the Guadalquivir River basin. Annual growth was low. Maximum ages observed were 5+ in males and 7+ in females. There was no significant difference in growth between sexes. Seasonal growth period started in May and continued for 2 to 6 months depending on age. The mean lengths of 1 + and 2+ age-groups decreased once the growth period had finished, probably related to reproductive stress and adverse ecological conditions, and this could explain the occurrence of Rosa Lee's phenomenon. Both sexes matured at the end of their second year of life (1+). There was a significant difference from 1: 1 in the overall sex ratio of 334 males to 464 females. Reproductive period started in March and lasted until May. Ch. p. willkommi was a multiple spawner that released two batches of eggs per female each year. The regression between fecundity ( F ) and fork length (l., mm) was: F =6.20 10³ L.^2.78. In females from age 2 + onwards, relative annual investment in somatic growth and reproduction was equivalent, implying that the same energy was allocated to reproduction as to maintenance/growth. Compared with other Ch. polylepis populations, the life-history patterns of this population, located in a small and seasonal stream in a southern latitude, were characterized by a low annual growth, a trade-off between reproduction and growth/maintenance, early maturity, low number of age-groups and high fecundity from multiple spawnings.     

New polypeptide components purified from mamba venom

New polypeptide components have been isolated from Dendroaspis angusticeps venom using chromatography. Two polypeptides containing 59 and 57 amino acids, called 'DaE1' and 'DaE2' respectively, have been purified to homogeneity and fully sequenced. Spectrometric analysis yielded masses of 6631.5 and 6389.0 Da, respectively. The polypeptides share 98 and 95% identity, respectively, with trypsin inhibitor E (DpE) of Dendroaspis polylepis polylepis. 'DaE' polypeptides inhibit Kv1.1 channels with an IC(50) value in the range of 300 nM. They can be considered as new dendrotoxins, albeit with fairly low affinity as compared to alpha-DTX. 'DaE' polypeptides do not affect Kir2.1 channels.     

Population structure,inbreeding and local adaptation within an endangered riverine specialist: the nase (Chondrostoma nasus)

Chondrostoma nasus is a cyprinid fish with highly specialized, ecologically and geographically distinct, ontogenetic trophic niches. Nase population numbers across their Swiss range have shown massive declines and many localized extinctions. In this study, we integrate genetic data (AFLP, microsatellite, mtDNA sequence) with phenotypic and demographic analyses to survey patterns of neutral and adaptive genetic diversity in all extant (and one extinct) Swiss nase populations, with the aim to delineate intraspecific conservation units (CUs) and to inform future population management strategies. We discovered two major genetically and geographically distinct population groupings. The first population grouping comprises nase inhabiting rivers flowing into Lake Constance; the second comprises nase populations from Rhine drainages below Lake Constance. Within these clusters there is generally limited genetic differentiation among populations. Genomic outlier scans based on 256 to 377 polymorphic AFLP loci revealed little evidence of local adaptation both within and among population clusters, with the exception of one candidate locus identified in scans involving the low genetic diversity Schanzengraben population. However, significant phenotypic differentiation in body shape between certain populations suggests a need for more intensive future studies of local adaptation. Our data strongly suggests that the two major population groups should be treated as distinct CUs, with any supplemental stocking and reintroductions sourced only from within the range of the CU concerned.     

A new endemic cyprinid species from the Danube drainage

Populations of endemic Croatian dace were found to belong to two different species, one of which is first described in this study. Telestes karsticus sp. nov. differed morphologically from Telestes polylepis in the total count of lateral line scales, number of gill rakers and the shape of the posterior margin of the anal fin. Morphological differences were corroborated with mtDNA analyses (with p-distance between T. polylepis and T. karsticus sp. nov. ranging between 3·2 and 4·1%; and the number of substitutions between 37 and 47). The newly described species is geographically very localized. It has been recorded from only four localities around Velika Kapela and Mala Kapela mountains in Croatia.     

A comparative study on morphology, growth rate and reproduction of Clarias gariepinus (Burchell, 1822), Heterobranchus longifilis Valenciennes, 1840, and their reciprocal hybrids (Pisces, Clariidae)

A detailed study on reproduction indicated that female C. gariepinus mature earlier (5–7 months) than female H. longifilis (12–14 months). In the reciprocal hybrids, female first sexual maturity was attained at 20–21 months. Both reciprocal hybrids and parental species displayed an equilibrated sex ratio. Macroscopical and microscopical observations revealed numerous abnormalities in gonadal development of the hybrids. GSI and fecundity in female hybrids were considerably lower than those found in the parental species. Moreover, intra-ovarian tumors occurred in 20% of the hybrids. In hybrid males, GSIs were generally higher than those found in the parental species, but the spermatozoa concentration in the semen was about 100 times less. Despite these abnormalities, viable larvae, resulting from F2 and backcross fertilizations, were obtained.     

Phylogeography of skinks (Chalcides) in the Canary Islands inferred from mitochondrial DNA sequences

Mitochondrial DNA (mtDNA) evolution was investigated in skinks of the genus Chalcides found in the Canary Islands ( Ch. sexlineatus, Ch. viridanus and Ch. simonyi ), together with some North African congenerics ( Ch. polylepis and Ch. mionecton ). Several sites were included within islands to cover areas of known within-island geographical variation in morphology. Skinks from the islands of El Hierro and La Gomera appear to be sister taxa. The relationships between this clade and the Tenerife and Gran Canarian skinks were not fully resolved, although the best working hypothesis indicated monophyly with the former, with the latter forming a closely related outgroup. Ch. simonyi from Fuerteventura was more distantly related to the Western Canary Island skinks and did not show close relationships with the North African species Ch. mionecton and Ch . polylepis . Possible colonization sequences for the four most Western Canary Islands were considered. El Hierro appears to have been colonized relatively recently from La Gomera, commensurate with the recent origin of this island, while dispersal between La Gomera and Tenerife and between Gran Canaria and Tenerife or La Gomera appears to have taken place considerably earlier. Substantial within-island haplotype divergence was found in Gran Canaria and Tenerife. This may be a result of recent periods of intense volcanic activity found within these two islands. Lower levels of within-island differentiation are found in La Gomera and El Hierro and may be explained by lower levels of volcanic activity during recent geological history and a more recent colonization, respectively.