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

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

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.This article is from American Fisheries Society Symposium 7 (2009): 1. Posted with permission/</p