[Show abstract][Hide abstract] ABSTRACT: Freshwater Fishes and Lampreys of Greece: An annotated checklist is the 8th volume of Monographs on Marine Sciences published by the Hellenic Centre for Marine Research (HCMR), Athens, Greece. This work provides a list of all species of fishes occuring in inland freshwaters; the most recent, carefully referenced account of its kind. The work is part of a project to compile and disseminate information on fishes at the Institute of Marine Biological Resources and Inland Waters (IMBRIW) of HCMR.
Monographs on Marine Sciences 8 edited by Hellenic Centre for Marine Research, 03/2015; Hellenic Centre for Marine Research., ISBN: 978-960-9798-06-8
[Show abstract][Hide abstract] ABSTRACT: Incomplete knowledge of biodiversity remains a stumbling block for conservation planning, and even occurs within globally important Biodiversity Hotspots. Although technical advances have boosted the power of molecular biodiversity assessments, the link between DNA sequences and species and the analytics to discriminate entities, remain crucial. Here, we present an analysis of the first DNA barcode library for the freshwater fish fauna of the Mediterranean Biodiversity Hotspot (526 spp.), with virtually complete species coverage (498 spp., 98% extant species). In order to build an identification system supporting conservation, we compared species determination by taxonomists to multiple clustering analyses of DNA barcodes for 3165 specimens. The congruence of barcode clusters with morphological determination was strongly dependent on the method of cluster delineation, but was highest with the GMYC model-based approach (83% of all species recovered as GMYC entity). Overall, genetic-morphological discontinuities suggest the existence of up to 64 previously unrecognized candidate species. We found reduced identification accuracy when using the entire DNA-barcode database, compared to analyses on databases for individual river catchments. This scale effect has important implications for barcoding assessments, and suggests that fairly simple identification pipelines provide sufficient resolution in local applications. We calculated EDGE (Evolutionarily Distinct and Globally Endangered) scores in order to identify candidate species for conservation priority, and argue that the evolutionary content of barcode data can be used to detect priority species for future IUCN assessments. We show that large-scale barcoding inventories of complex biotas are feasible and contribute directly to the evaluation of conservation priorities. This article is protected by copyright. All rights reserved.
[Show abstract][Hide abstract] ABSTRACT: Article describing the background, structure and vision of the Institute of Marine Biological Resources and Inland Waters of HCMR. Published in the Greek language in the periodical Alieftika Nea (Fisheries News).
[Show abstract][Hide abstract] ABSTRACT: A development series of Atherina boyeri (Atherinidae: Pisces) larvae from Lake Trichonis is described and illustrated. In view of the uncertainty concerning the systematic relationship between A. boyeri, A. presbyter, and A. mochon pontica, a comparison of larval characters of the three taxa is attempted, based on the present material and published descriptions of the latter two taxa. The comparison reveals remarkable morphological similarities, but also a confusing pattern of variation which raises the same systematic questions as the comparison of adults.
Israel Journal of Zoology 04/2013; 43(2):159-166. DOI:10.1080/00212210.1997.10688900 · 0.61 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The genetic structure and the phylogenetic relationships among five Balkan populations of trout Salmo trutta that have been classified earlier into five different taxa were studied, using microsatellite and mitochondrial DNA (mtDNA) analyses. The pattern of population differentiation observed at microsatellites differed to that depicted by mtDNA variation, yet both methods indicated a very strong partitioning of the genetic variation among sampling locations. Results thus suggest that conservation strategies should be directed towards preserving the genetic integrity and uniqueness of each population.
Journal of Fish Biology 12/2011; 79(7):1950-60. DOI:10.1111/j.1095-8649.2011.03136.x · 1.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The patterns of MHC diversity were studied at UAA and DAB1 loci and the two domains involved in the recognition of antigenic peptides (α2 and β1, respectively) in eight Ladigesocypris ghigii populations inhabiting streams and a concrete reservoir, in order to understand the significance of these genes in bottlenecked
populations of an endemic species and develop conservation rationale. In agreement with previous study employing RAPD and
mtDNA markers (Mamuris et al., Freshw Biol 50:1441–1453, 2005), both loci exhibited a very low level of polymorphism with only two and four alleles detected for UAA and DAB1, respectively. The functional MHC diversity was even lower since UAA alleles were distinguished by a single synonymous substitution. The type of habitat did not affect the level of polymorphism.
Our data suggest that DAB1 polymorphism might be the outcome of the positive selection, imposed by the temporal and spatial variation of pathogen load,
and the genetic drift as a result of successive habitat shrinkage and deterioration by water abstraction year after year.
The populations studied were significantly less diverged at MHC loci than expected based on nuclear and mtDNA markers, suggesting
that common parasites might act as causative factors to homogenize selection. Sufficient epidemiological data are required
for the interpretation of the results and decision-making on suitable conservation actions.
[Show abstract][Hide abstract] ABSTRACT: Adult gilthead sea bream Sparus aurata and sea bass Dicentrarchus labrax were exposed for 24 and 48 h, respectively, to two concentrations of ammonia each (mean values of 3·34 and 13·10 mg l(-1) TA-N in S. aurata; 2·99 and 11·90 mg l(-1) TA-N in D. labrax). Light microscopy and computerized morphometry were used to evaluate ammonia-induced alterations in skin structure during exposure and following recovery in normal water. In S. aurata, ammonia exposure induced a concentration-dependent increase in the number (hyperplasia) of neutral mucous cells (mc), with peak values at 24 h recovery after exposure. An increase in the dispersion of melanosomes in skin melanocytes was also observed in the dermis and occasionally in the epidermis of S. aurata, with peak values at 24 h of ammonia exposure. Exposure of D. labrax to ammonia had, likewise, concentration-dependent effects on mucous secretion. Of the two types of mc in this species, there was an increase in the number of the neutral mc and a reduction in the much more numerous acid mc, with peak values at 24 and 48 h, respectively, of ammonia exposure. The more intense mucous secretion in D. labrax compared to S. aurata could be related to the lower tolerance to ammonia in D. labrax, as reported elsewhere. Finally, the increase in melanosome dispersion was less evident in D. labrax, due to highly variable control values. These morphological alterations to the skin could be useful indicators of non-specific stress in cultured fishes.
Journal of Fish Biology 04/2011; 78(4):1152-69. DOI:10.1111/j.1095-8649.2011.02922.x · 1.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to determine the phylogeographic structure of the brackish-hypersaline cyprinodont fish Aphanius fasciatus (Valenciennes, 1821), using sequencing and RFLP analysis of a 1,330 bp mitochondrial DNA segment containing part of the 16S rRNA gene as well as the genes for tRNA-Leu, NADH subunit 1 and tRNA-Ile. Individuals were collected from 13 different sites in Greece and Turkey, while seven published A. fasciatus sequences were also included to cover the area of distribution of the species. Pairwise sequence divergence values ranged from 0 to 4.51%. Congruent phylogenies were recovered with maximum likelihood, maximum parsimony and neighbour-joining methods. All analyses revealed two main groups. The first group consists of populations from almost all localities that drain into the Aegean Sea. The second group comprises the remaining population samples, which in some cases seem to consist of population-specific subgroups. Our results show that vicariant events have predominantly affected the evolution of A. fasciatus, with the Messinian salinity crisis having shaped the present genetic structure of its populations. Additionally, the life-history traits of the species, which determine a low potential for dispersal, coupled with the typical fragmentation of brackish-hypersaline water habitats have led to a high degree of isolation of A. fasciatus populations, even at restricted spatial scales. Analysis of the partitioning of the total amount of polymorphism with analyses of molecular variance (AMOVA) gave a value of F ST = 84.6%. Potential conservation policies concerning A. fasciatus should also consider the low-genetic variability in the majority of its populations and the presence of fixed haplotypes in some of them.
[Show abstract][Hide abstract] ABSTRACT: Summary1. 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.
[Show abstract][Hide abstract] ABSTRACT: Ladigesocypris ghigii (Gianferrari, 1927), commonly called gizani, is an endangered freshwater fish endemic to the Greek island of Rhodes. The spawning behaviour of gizani was studied in aquaria, to develop an artificial breeding technique for this endangered species. Spawning in captivity was recorded over 41 spawning days between 15 February and 14 July 2001, under constant temperature (18 or 21°C) and photoperiod 14L/10D. The number of spawning acts in a day was 82 ± 28. No aggressiveness and no territoriality were developed. The mating system of the fish was polygamous, with females spawning more than once. In captivity, eggs are laid either on aquatic plants or on gravel, while in nature fish spawn mainly on algae and plants. The latter suggests that, as far as breeding substrate is concerned, gizani is an opportunistic species using different substrates when necessary.
[Show abstract][Hide abstract] ABSTRACT: The yearly gonadal cycle of two Kinneret teleosts, Barbus longiceps and Capoeta damascina and of their hybrid, was assessed by measuring the gonadosomatic index (GSI) in both sexes, as well as the spermatozoan index (SPI) in the males. SPI was established through a computerized analysis system, using light microscopy images of histological preparations of the testes.
Barbus longiceps specimens had highest GSI in March, 6.31 for males and 1.40 for females. Capoela damascina had highest GS1 in January, 6.63 for males and 6.88 for females. In the male-like hybrids, the highest GSI was 5.57 in February, and in female-like hybrids 1.83 in March; no gametes were ever formed in hybrid gonads. The highest SPI appeared in B. longiceps in April, while in C. damascina the highest SPI was found in March. In both species, the highest SPI was attained several weeks after the highest GSI was observed. It is suggested that the peak of the breeding season of both species is actually represented by the highest SPI. In males, the decreasing GSI, which corresponds to the highest SPI, represents the loss of gonad weight, which is due to the elimination of the spermatid residual bodies, prior to spermiation. In the females the decreasing GSI is the result of ovulation, and characterizes the peak of spawning activity.
Journal of Fish Biology 04/2005; 43(6):865 - 875. DOI:10.1111/j.1095-8649.1993.tb01161.x · 1.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Testicular ultrastructure was studied in Barbus longiceps, Capoeta damascina and their natural hybrid. The testes of these teleosts belong to the unrestricted or lobular type. Germ cell morphology is similar in the parental males. In the hybrid, spermatogenesis does not extend beyond the pachytene of the first meiotic division, probably due to the unsuccessful pairing of the homologous chromosomes. Hybrid testes are occupied mainly by degenerating primary spermatocytes, at the leptotene and pachytene stages. In both parents and the hybrid, Sertoli and Leydig cells are characterized by the presence of granular endoplasmic reticulum and of mitochondria with tubular cristae. Due to the arrest of spermatogenesis, the male germ cell protective barrier is absent in the hybrid. Germ cell nuclear size was measured by a computerized analysis system, using light-microscopy images. In the parents and the hybrid, germ cells attain a uniform inter-individual nuclear size when they reach the first meiotic prophase. The nuclear size of primary spermatocytes is similar among the three groups of fish, possibly reflecting their close genetic relationship.
Journal of Fish Biology 03/2005; 49(3):458 - 468. DOI:10.1111/j.1095-8649.1996.tb00041.x · 1.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This database and analysis includes a review of all published and grey literature items that may be useful for the implementation of the WFD 2000/60 in Greece. The report was commissioned by the Ministry of Development.