The biology and ecology of Valencia letourneuxi Sauvage 1880 (Valenciidae) - Prospects for conservation

Data are provided on the distribution, abundance, early development and biology of the endangered Greek endemic species Valencia letourneuxi Sauvage 1880, along with a record of its occurrence at new localities. V. letourneuxi is a small-bodied and short-lived insectivorous species, exhibiting cryptic colouration and sexual dimorphism. It matures in the first year of life, reproduces serially in late spring and summer, and deposits spherical eggs, around 2 mm, on aquatic plants. Most morphometric characters show size-specific trends, which complicate comparisons among populations or with other species. Of specific systematic importance is the relative position of the anal and dorsal fins, which remains almost unaltered throughout development, and allows safe distinction from A. fasciatus. The species was found mostly in deep areas with clean and slow running water, usually associated with freshwater springs. Rich submerged vegetation is the prominent ecological feature of all sites in which the species was found. Using as criteria of rarity the limited geographic distribution, the confinement of the species in few localities of each aquatic system and the low local densities, V. letourneuxi can be characterised as a "restricted and locally rare species". The restricted distribution, coupled with the narrow ecological requirements, makes the species vulnerable to extinction. Its disappearance from at least four aquatic systems and the serious population decline in a number of other systems seems to be connected with habitat loss or degradation caused by human activities. The prospects of conservation are discussed

Dužinsko – maseni odnosi i kondicijski čimbenici gavuna veleljuskaša Atherina boyeri (Risso, 1810) iz komercijalnih i eksperimentalnih ulova u jezeru Trichonis (zapadna Grčka)

Total length-weight relationships (LWRs) from 3583 individuals of Atherina boyeri (Risso, 1810) caught in Lake Trichonis (Western Greece), using a commercial encircled net and experimental Nordic type benthic and pelagic multi-mesh gillnets, were estimated during 2019-2020. The variation of the parameter b for all seasons combined was significantly allometric, for both encircled towed and gillnets, with a quite robust fit (R2 equals 0.925 and 0.947, respectively) and values equal to 2.254 and 2.089, respectively. The specimens were significantly lighter in summer than in the other seasons. The slopes of the LWRs significantly differ between seasons and exhibited relatively low values when compared to other ecosystems worldwide and in the same ecosystem in previousperiods of time. Τhe estimated values of the Le Cren index were significantly higher than the Allometricand the Fulton ones.Dužinsko-maseni odnosi (LWRs) su izračunati za 3583 jedinke gavuna veleljuskaša Atherina boyeri (Risso, 1810) ulovljenih u jezeru Trichonis (Zapadna Grčka), tijekom razdoblja 2019-2020. Jedinke su ulovljene komercijalnim mrežama i eksperimentalnim mrežama nordijskog tipa bentoskih i pelagičnih mreža različitih oka. Varijacija parametra b za sva godišnja doba bila je značajno alometrijska, i za zaokružne povlačne mreže i za mreže stajačice, s prilično robusnim vrijednostima koeficijenta korelacije (r2 je 0,925 odnosno 0,947) i vrijednostima jednakim 2,254 odnosno 2,089. Primjerci su ljeti bili znatno lakši nego u ostalim godišnjim dobima. Nagibi LWR-a značajno se razlikuju između godišnjih doba i pokazali su relativno niske vrijednosti u usporedbi s drugim ekosustavima diljem svijeta i u istom ekosustavu u prethodnim vremenskim razdobljima. Procijenjene vrijednosti Le Crenovog indeksa bile su znatno veće od alometrijskih i Fultonovih

The freshwater ichthyofauna of Greece - an update based on a hydrographic basin survey

Distribution records (historical, contemporary) for native and non-native freshwater fish species from 105 hydrographic basin areas were compiled and analysed in order to develop a nation-wide inventory (including transboundary river basins). Overall, 162 species, including diadromous and euryhaline, with documented occurrence records in freshwaters, and taxa of unclarified taxonomic status, are accommodated in the distributional compilation. An annotated checklist summarises the confirmed ichthyofauna of Greek freshwaters (161 species); a provisional supplementary list contains species recorded in brackish waters (55 species). In comparison to the last published (1991) checklist of freshwater fish of Greece, the present checklist shows an increase in species number of 53% (56 species). This increase has resulted mainly from taxonomic re-evaluations of existing taxa on the basis of new information and adoption of a new systematic concept. The current trend, as reflected in recent ichthyological publications, is towards abandonment of the biological species concept (BSC) and adoption of the phylogenetic species concept (PSC) for the delineation of species boundaries. The practical implications of the change in species concept on biodiversity conservation and watershed management are discussed. An overview of the composition and characteristics of the freshwater fish fauna of Greece is provided, especially with regard to the native and introduced status of species, and the spatial patterns of species richness and endemism. This systematic inventory may assist in efforts to develop nation-wide surface water bioassessment tools within the demands of the Water Framework Directive (WFD); it may further promote biodiversity conservation and biologically-orientated fishery management approaches

Novel Relationships among Lampreys (Petromyzontiformes) Revealed by a Taxonomically Comprehensive Molecular Data Set

The systematics of lampreys was investigated using complete mitochondrial cytochrome b sequences from all genera and nearly all recognized species. The families Geotriidae and Petromyzontidae are monophyletic, but the family Mordaciidae was resolved as two divergent lineages at the base of the tree. Within Petromyzontidae, the nonparasitic Lethenteron sp. S and Okkelbergia aepyptera were recognized as distinct lineages, Lethenteron morii and Lampetra zanandreai were moved to new genera, a sister species relationship was recovered between Caspiomyzon wagneri and Eudontomyzon hellenicus, and a clade was recovered inclusive of Entosphenus hubbsi and western North American Lampetra (L. ayresii and L. richardsoni). The placement of E. hellenicus as the sister species to C. wagneri reduces the number of genera comprised entirely of parasitic species to two, Geotria and Petromyzon. The recognition of distinct lineages for O. aepyptera and Lethenteron sp. S recognizes, for the first time, lineages comprised entirely of nonparasitic species. Apart from the results mentioned above, monophyly was supported for the multispecific genera Entosphenus, Eudontomyzon, Ichthyomyzon, Lampetra (restricted to European species), and Lethenteron. Intergeneric relationships within Petromyzontidae were poorly resolved, but separate clades inclusive of Entosphenus and Tetrapleurodon (subfamily Entospheninae) and one comprised of Eudontomyzon, Lampetra, and Okkelbergia were recovered

CONTRIBUTION IN THE STUDY OF REPRODUCTION OF THE NATURAL HYBRID BETWEEN BARBUS LONGICEPS AND CAPOETA DAMASCINA (PISCES, CYPRINIDAE), IN TIBERIAS LAKE (ISRAEL)

Η ΑΝΑΠΤΥΞΗ ΤΩΝ ΓΟΝΑΔΩΝ ΚΑΙ Η ΑΥΞΗΣΗ ΜΕΛΕΤΗΘΗΚΑΝ ΣΤΟ ΦΥΣΙΚΟ ΥΒΡΙΔΙΟ ΤΩΝ ΕΙΔΩΝ BARBUS LONGICEPS ΚΑΙ CAPOETA DAMASCINA, ΣΤΗ ΛΙΜΝΗ ΤΗΣ ΤΙΒΕΡΙΑΔΑΣ, ΣΤΟ ΙΣΡΑΗΛ. ΗΣΩΜΑΤΙΚΗ ΑΥΞΗΣΗ ΚΑΙ Ο ΡΥΘΜΟΣ ΕΠΕΝΔΥΣΗΣ ΤΟΥ ΥΒΡΙΔΙΟΥ ΗΤΑΝ ΕΝΔΙΑΜΕΣΑ ΜΕΓΕΘΗ, ΣΕ ΣΧΕΣΗ ΜΕ ΤΑ ΓΟΝΙΚΑ ΕΙΔΗ. ΟΙ ΑΝΑΠΑΡΑΓΩΓΙΚΕΣ ΠΕΡΙΟΔΟΙ ΤΩΝ ΓΟΝΙΚΩΝ ΕΙΔΩΝ ΠΡΟΣΔΙΟΡΙΣΤΗΚΑΝ ΜΕ ΤΗ ΧΡΗΣΗ ΤΟΥ ΓΟΝΑΔΟΣΩΜΑΤΙΚΟΥ ΚΑΙ ΣΠΕΡΜΑΤΟΖΩΙΚΟΥ ΔΕΙΚΤΗ ΚΑΙ ΜΕ ΙΣΤΟΛΟΓΙΑ ΤΩΝ ΓΟΝΑΔΩΝ. Η ΑΝΑΠΤΥΞΗ ΤΩΝ ΓΟΝΑΔΩΝ ΣΤΟ ΥΒΡΙΔΙΟ ΗΤΑΝ ΑΝΩΜΑΛΗ. ΑΝΑΜΕΣΑΣΤΑ 39 ΥΒΡΙΔΙΑ ΤΟΥ ΔΕΙΓΜΑΤΟΣ, 5 ΗΤΑΝ ΑΡΣΕΝΙΚΑ ΜΕ ΑΤΕΛΗ ΣΠΕΡΜΑΤΟΓΕΝΕΣΗ, 30 ΘΗΛΥΚΑ ΜΕ ΑΝΩΜΑΛΗ ΩΟΓΕΝΕΣΗ ΚΑΙ 4 ΔΟΜΙΚΑ ΕΡΜΑΦΡΟΔΙΤΑ ΜΕ ΑΤΕΛΗ ΓΑΜΕΤΟΓΕΝΕΣΗ. Η ΓΑΜΕΤΟΓΕΝΕΣΗ ΣΕ ΟΛΑ ΤΑ ΥΒΡΙΔΙΑ ΒΡΕΘΗΚΕ ΝΑ ΣΤΑΜΑΤΑ ΣΤΗΝ ΠΡΟΦΑΣΗ ΤΗΣ ΠΡΩΤΗΣ ΜΕΙΩΤΙΚΗΣ ΔΙΑΙΡΕΣΗΣ. ΑΝ ΚΑΙ ΣΤΕΙΡΑ ΤΑ ΥΒΡΙΔΙΑ ΚΑΤΕΙΧΑΝ ΔΕΥΤΕΡΕΥΟΝΤΑ ΧΑΡΑΚΤΗΡΙΣΤΙΚΑ ΤΟΥ ΦΥΛΟΥ. Η ΑΝΑΛΥΤΙΚΗ ΜΟΡΦΟΜΕΤΡΙΑ ΜΕ ΗΛΕΚΤΡΟΝΙΚΟ ΥΠΟΛΟΓΙΣΤΗ ΧΡΗΣΙΜΟΠΟΙΗΘΗΚΕ ΣΑΝ ΕΝΑ ΕΠΙΠΡΟΣΘΕΤΟ ΜΕΣΟ ΑΝΑΓΝΩΡΙΣΗΣ ΤΩΝ ΓΕΝΝΗΤΙΚΩΝ ΚΥΤΤΑΡΩΝ. ΟΙ ΜΕΤΡΗΣΕΙΣ ΤΟΥ ΜΕΓΕΘΟΥΣ ΤΩΝ ΠΥΡΗΝΩΝ ΤΩΝ ΓΕΝΝΗΤΙΚΩΝ ΚΥΤΤΑΡΩΝ ΣΥΓΚΡΙΘΗΚΑΝ ΣΤΑΤΙΣΤΙΚΑ.GONAD DEVELOPMENT AND SOMATIC GROWTH WERE STUDIED IN THE NATURAL HYBRID BETWEEN BARBUS LONGICEPS AND CAPOETA DAMASCINA FROM TIBERIAS LAKE, IN ISRAEL. HYBRID SOMATIC GROWTH AND DRESSING RATE WERE INTERMEDIATE COMPARED TO THE PARENTAL SPECIES. THE REPRODUCTIVE PERIODS OF THE PARENTAL SPECIES WERE DETERMINED USING GONADOSOMATIC AND SPERMATOZOAN INDEXES AND BY GONAD HISTOLOGY. HYBRID GONAD DEVELOPMENT WAS IMPAIRED. AMONG 39 HYBRID SPECIMENS SAMPLED, 5 WERE FOUND TO BE MALES WITH ARRESTED SPERMATOGENESIS; 30 FEMALES WITH ABNORMAL OOGENESIS AND 4 STRUCTURAL HERMAPHRODITES WITH ARRESTED GAMETOGENESIS. IN ALL HYBRIDS GAMETOGENESIS WAS ARRESTED IN THE PROPHASE OF THE FIRST MEIOTIC DIVISION. ALTHOUGH STERILE, HYBRIDS POSSESED SECONDARY SEX CHARACTERISTICS. COMPUTERIZED MORPHOMETRY WAS USED AS AN ADDITIONAL TOOL FOR GERM CELL IDENTIFICATION; NUCLEISIZE OF DIFFERENT GERM CELL TYPES WERE CALCULATED AND STATISTICALLY TREATED

Aphanius almiriensis, a new species of toothcarp from Greece (Teleostei: Cyprinodontidae)

Volume: 114Start Page: 13End Page: 3

Genetic variation in populations of the endangered fish Ladigesocypris ghigii and its implications for conservation

1. The genetic variation of the endangered freshwater fish Ladigesocypris ghigii, endemic to the island of Rhodes (Greece), was investigated for nine populations, originating from seven different stream systems and a reservoir, both at the mtDNA and nuclear level, in order to suggest conservation actions. 2. Both restriction fragment length polymorphism analysis of five segments of mitochondrial DNA (ND-5/6, COI and 12S-16S rRNA) amplified by polymerase chain reaction, and random amplified polymorphic DNA analysis, revealed extremely low levels of intra-population polymorphism. It is highly likely that the low intra-population variability is the result of successive bottleneck events evident in shrinkage and expansion of the populations year after year, which may have led to a complete loss of several genotypes and haplotypes, and an increased degree of inbreeding. 3. Inter-population genetic structuring was high, with fixation of haplotypes within six of the nine populations and fixation of alleles within populations originating from different waterbodies. It is probable that all haplotypes and/or alleles found were initially represented in all populations. However, because of the long time of isolation coupled with successive bottleneck and subsequent genetic drift, common mtDNA haplotypes and alleles among the populations may have become rare or extinct through stochastic lineage loss. 4. Although nucleotide divergence among haplotypes was very shallow, half of the haplotypes recorded (three of six), resulted from nucleotide changes on the 12S-16S rRNA segments, which are the most conserved part of the mitochondrial genome. This fact may indicate that the observed genetic variation did not necessarily result only from the retention of ancestral polymorphism, but may have arisen through mutation and complete lineage sorting over a relatively small number of generations, once the populations had become isolated from one another. 5. Our data suggest that two of the L. ghigii populations may be on independent evolutionary trajectories. Considering that each population appears so far well adapted within each site, all populations should be managed and conserved separately