George Koumoundouros

George Koumoundouros
University of Crete | UOC · Department of Biology (School of Sciences and Engineering)

32.71
 · 
BSc, MSc, PhD

About

90
Publications
13,659
Reads
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3,382
Citations
Research Experience
July 2019 - present
University of Crete
Position
  • Professor
January 2011 - present
University of Crete
Position
  • Associate Professor
February 2003 - January 2011
University of Patras
Position
  • Assistant Professor

Publications

Publications (90)
Article
Full-text available
Over the next century, climate change of anthropogenic origin is a major threat to global biodiversity. We show here that developmental temperature can have significant effects on zebrafish cardiac anatomy and swimming performance. Zebrafish embryos were subjected to three developmental temperature treatments (TD = 24, 28 or 32 °C) up to metamorpho...
Article
The development of skeletal abnormalities is a frequent problem of quality in finfish hatcheries, resulting from unfavourable environmental conditions, often under the control of genetic background. In the present study, the heritability of jaw abnormalities in Gilthead seabream was estimated at the end of the larval rearing phase (39 dph, days pos...
Article
Caudal‐fin lepidotrichia is composed of numerous segments, which are linked to each other by intersegmental joints. During fish growth, lepidotrichia elongate by the addition of new segments at their distal margin, whereas the length of each segment remains constant after it is formed. In the present paper, we examined whether the water temperature...
Article
Full-text available
Haemal lordosis is a frequent abnormality of the vertebral column. It has been recorded to develop in different finfish species, during the hatchery rearing phase. Under certain conditions, this abnormality reaches a high prevalence and severity degree, with significant effects on the external morphology of the fish. We show that haemal lordosis re...
Article
The temperature sex determination (TSD) mechanism in the European sea bass (Dicentrarchus labrax L.) was studied in respect to: a) the TSD sensitivity during the different developmental stages; and b) the intrapopulation correlation of sex determination with the growth rate up to the end of the TSD-sensitive period. At the stage of half-epiboly, eg...
Article
Full-text available
Titanium dioxide nanoparticles (TiO2-NPs) are among the most popular manufactured and widely used nanoparticles. They are released into the environment, affecting terrestrial and aquatic ecosystems, with unexpected consequences to organisms and human health. The present study investigates the mediated toxicity imposed to the freshwater fish species...
Article
The anabolic effect of exercise on muscles and bones is well documented. In teleost fish exercise has been shown to accelerate skeletogenesis, to increase the bone volume, and to change the shape of vertebral bodies. Still, increased swimming has also been reported to induce malformations of the teleost vertebral column, particularly lordosis. This...
Article
Among pollutants, nanoparticles (NPs) consist a potential environmental hazard, as they could possibly harm the aquatic and terrestrial ecosystems while having unpredictable repercussions on human health. Since monitoring the impact of NPs on aquatic and terrestrial life is challenging, due to the differential sensitivities of organisms to a given...
Article
Morphometric characters have traditionally been used to describe the population structure of fishes. Body shape variation, which is often environmentally induced, may provide a good record of short-term population structuring. However, factors unrelated to environmental or genetic influences on body morphology may complicate sampling and the use of...
Book
Skeletal anomalies in reared european fish larvae and juveniles. Part 1: Normal and anomalous skeletogenic processes
Book
Skeletal anomalies in reared european fish larvae and juveniles. Part 2: Main typologies, occurences and causative factors
Article
The osteological development of the vertebral column and fins in shi drum Umbrina cirrosa was studied in order to improve knowledge for its introduction in Mediterranean aquaculture. The osteological development was studied in 171 individuals, of total length (LT) from 2·7 to 30·2 mm that were reared under the mesocosm technique. Vertebral ontogeny...
Article
Full-text available
Ocean acidification is a recognized consequence of anthropogenic carbon dioxide (CO2) emission in the atmosphere. Despite its threat to marine ecosystems, little is presently known about the capacity for fish to respond efficiently to this acidification. In adult fish, acid-base regulatory capacities are believed to be relatively competent to respo...
Article
This study focused on the anatomy and ontogeny of saddleback syndrome (SBS) in reared European sea bass. The abnormality was detected at an unusually high frequency (12-94%) during a routine quality control in a commercial hatchery. Anatomically the abnormality was mainly characterized by the loss of 1-5 hard spines and severe abnormalities of the...
Article
In this study, a scale of quality for the body shape of Gilthead seabream was developed. For this purpose , a questionnaire survey was carried out to study the preferences of consumers for the body shape of seabream. Furthermore, the variation in body shape in reared seabream was studied under two rearing environments (sea cages vs. tanks) and in c...
Article
Finfish present a great ability to modify their phenotype in response to environmental conditions especially in the early ontogenetic period. Such plastic phenotypic responses have a great importance, from both the ecological and aquaculture point of view. The present study examined the effect of water temperature on the ontogeny and juvenile pheno...
Article
Full-text available
Understanding critical ontogenetic transitions in the life of fish, such as metamorphosis, is of prime importance for determining the factors that affect survival probabilities and control recruitment levels. Metamorphosis involves a plethora of changing characters and its definition requires a multi-parametric approach. In the present study, mean...
Article
A new type of vertebral malformation is described, consisting of deformed cartilaginous neural and haemal processes and the compression and fusion of vertebral bodies. The malformation is designated as haemal vertebral compression and fusion (haemal VCF). We studied the aetiology of the malformations and described microanatomical histopathological...
Article
Full-text available
This critical review summarizes the knowledge about fish skeletal tissues and inherent normal and anomalous development. Particular emphasis is given to existing literature on reared European fishes. The aim was to identify the main gaps of knowledge that require to be filled, in order to precociously identify anomalous developmental patterns that...
Article
Full-text available
The presence of skeletal anomalies in farmed teleost fish is currently a major problem in aquaculture, entailing economical, biological and ethical issues. The common occurrence of skeletal abnormalities in farmed fish and the absence of effective solutions for avoiding their onset or definitely culling out the affected individuals as early as poss...
Article
Although zebrafish is used as a major model species for understanding a number of biological functions and mechanisms involved, there is practically no information on the nutritional requirements of this cyprinid. The rearing practices, especially with regard to feeds and feeding, also vary considerably. To obtain base line information on the nutri...
Article
Vitamins D and C are essential in many physiological functions. Vitamin D, a fat soluble vitamin, is crucial to preserve calcium and phosphate homeostasis and to protect the skeletal integrity. This hormone functions through the vitamin D receptor (VDR) inducing the expression of various calcium binding and transport proteins in the intestine to st...
Article
The purpose of this study was to examine the effects of vitamin A levels in the larval diet of Dicentrarchus labrax, (a) on the shape of juvenile skeleton and (b) on the development of pelvic fins. To exclude the side-effects of skeletal abnormalities on skeleton shape, morphometric analysis was performed on normal individuals only. Geometric morph...
Conference Paper
Background / Purpose: Developmental temperature plays a principal role in the ontogeny of fish. However, its effect on the gene expression pattern had not been previously attempted for zebrafish.The optimal developmental temperature for zebrafish is 28°C. We performed two experiments where zebrafish Affymetrix microarrays of 15,509 probe sets wer...
Article
We examined the effect of temperature during the early development on the phenotypic plasticity of Danio rerio. The effect of temperature was examined during two different early developmental periods of 280°d (the product of days × temperature) each, 28-308°d or 280-560°d, by subjecting the experimental populations to three different water temperat...
Article
The development of skeletal deformities is an important problem for finfish hatcheries. In the present paper, the effect of water temperature on the development of skeletal deformities in Sparus aurata was examined. Six combinations of three temperatures (16, 19, and 22 °C) were applied during three ontogenetic windows: the autotrophic (embryonic a...
Article
Full-text available
The present study attempts to highlight the value of multi-character approaches for defining thresholds in fish ontogeny, like the onset of the juvenile period. We developed techniques to objectively define the transition from larval to juvenile development using morphometric as well as morphological characters and exemplify the multi-character app...
Article
The influence of dietary vitamin D3 (VD3) on survival, growth and morphogenesis during the larval development of European sea bass (Dicentrarchus labrax) was evaluated until 45 days post hatching. Diets contained 4% of the standard vitamin mix (VM) recommended by the National Research Council (NRC) and incorporated 0, 19.2, 38.4, or 140 IU of VD3 p...
Chapter
Full-text available
This review presents the state of the art of morpho-anatomical abnormalities in Mediterranean marine finfish culture. Morpho-anatomical abnormalities are presented in respect to the affected anatomical area, their ontogeny, known causative factors and their effects on the biological performance of the fish. Present literature clearly demonstrates t...
Article
The purpose of this study was to examine the impact of graded levels of dietary vitamin A on sea bass larval performances and to determine optimal retinol levels at different larval stages to avoid specific skeletal malformations. Retinol was incorporated into larval feeds at 0, 5,10,15, 25, 35 and 70 mg kg(-1) dry matter (giving rise to RET0, RET5...
Article
The vulnerability of embryonic and larval stages of European sea bass Dicentrarchus labrax to environmental temperature and the longer-term consequences for the early juveniles was demonstrated. This phenotypic plasticity was highlighted by subjecting D. labrax at 15.2 +/- 0.3 or 20.0 +/- 0.4 degrees C (mean +/-s.d.) up to metamorphosis and then at...
Article
The critical swimming speed (Ucrit) of gilthead seabream (Sparus aurata, Linnaeus 1875) was studied in two ontogenetic phases, early (13.7-18.7 mm total length, TL) and late metamorphosis (20.4-34.3 mm TL, after the full development of fin meristics and during squamation ontogeny), under four exercise temperatures (15, 20, 25 and 28 °C). Both the e...
Article
The saddleback syndrome is recorded for the first time in a wild fish population of the Mediterranean Sea. The deformed specimen belongs to Sparisoma cretense and presents the typical saddleback phenotype of missing spines in the dorsal fin. (c) 2008 The Author Journal compilation (c) 2008 The Fisheries Society of the British Isles.
Article
Summary The present study investigates the effect of water temperature on the development of deformities during embryonic and larval stages of European sea bass, Dicentrarchus labrax (L.). Two temperature conditions were examined in duplicate by studying the presence of skeletal deformities in a sample of 45 to 51 fish taken from each population at...
Article
To exam whether the temperature experienced by fishes at early developmental stages can influence their phenotype at subsequent stages, the model species used, European sea bass Dicentrarchus labrax was subjected to water temperatures of 15 or 20 degrees C during the half-epiboly stage until the metamorphosis. Meristic and morphometric characters a...
Article
Full-text available
A mean length at metamorphosis (Ljuv) is defined for Diplodus sargus using a multivariate analysis of morphometric characters. The Ljuv corresponds well to significant changes in relative otolith growth and otolith shape (coefficients of Elliptic Fourier Analysis). Introduction In comparative studies of fish development an ontogenetic index is usu-...
Conference Paper
Full-text available
A mean length at metamorphosis (Ljuv) is defined for Diplodus sargus using a multivariate analysis of morphometric characters. The Ljuv corresponds well to significant changes in relative otolith growth and otolith shape (coefficients of Elliptic Fourier Analysis).
Conference Paper
Full-text available
A mean length at metamorphosis (Ljuv) is defined for Diplodus sargus using a multivariate analysis of morphometric characters. The Ljuv corresponds well to significant changes in relative otolith growth and otolith shape (coefficients of Elliptic Fourier Analysis).
Article
Lordosis is one of the most severe deformities developing in reared fish; evaluating its effects on fish and aquaculture industry has been difficult to establish since there is no objective way of quantifying its severity and impact on the final product's image, fish shape. The effect of lordosis on body shape was analysed by geometric morphometric...
Article
Abstract Shape ontogeny of Diplodus puntazzo was studied during the larval and metamorphosis phase (2.6–33.0 mm total length (TL)) by means of geometric morphometrics. Additionally, shape comparison was performed between newly settled wild individuals of D. puntazzo (11.0–18.0 mm TL) and reared of the same TL range. Results clearly demonstrated tha...
Article
We tested the effect of water-temperature during the larval phase on sea bass sensitivity to current-induced lordosis. During larval rearing phase, fish were subjected to two different water temperatures (15 or 20 °C), with the rest of the rearing parameters remaining identical between the different populations. During the pregrowing phase, the dif...
Article
Full-text available
The aim of this EU ORCIS project was to optimise the rearing conditions of larval and juvenile sea bass (Dicentrarchus labrax) such that the incidence of lordosis was significantly reduced and coordinated musculo-skeletal growth was improved. This was achieved through an integrated, multidisciplinary approach where an understanding of the underlyin...
Article
The normal development of the vertebral column and of the fins in Diplodus puntazzo (Cetti, 1777) was studied. The ontogenetic pattern of the skeleton follows that described in all other Sparidae studied so far: the onset of the ontogeny of the vertebral column is at 4.9 mm total length (TL) with the formation of the first neural processes, while t...
Article
Abstract The ontogeny of shi drum Umbrina cirrosa (Linnaeus 1758), a candidate new species for aquaculture, was studied throughout the entire larval phase. Geometric morphometric analysis revealed two clear inflection points (7.0 and 12.7 mm total length, TL) in the shape ontogeny of this species, separating the studied period into three phases of...
Article
Temperature is one of the most critical environmental factors for fish ontogeny, affecting the developmental rate, survival and phenotypic plasticity in both a species- and stage-specific way. In the present paper we studied the egg and yolk-sac larval development of Pagellus erythrinus under different water temperature conditions, 15°C, 18°C and 2...
Article
In the current paper we present the rearing methodology of common dentex (Dentex dentex), a promising candidate for Mediterranean marine aquaculture, from the larval to the on-growing phase. The results are discussed in terms of the efficiency of rearing methodology followed, for the mass production of the species.
Article
The osteological ontogeny of Pagellus erythrinus (Linnaeus, 1758) and its temperature-induced plasticity is studied. The ontogeny of the skeleton follows the pattern described in all other Sparidae studied so far: the onset of the ontogeny of the vertebral column and the caudal fin is at 4.3 mm total length (TL) and the completion at 17.6 and 15.4...
Article
Depression of the dorsal profile accompanied by kyphosis and, in most of the cases, haemal lordosis was observed in reared Diplodus sargus. The ontogeny and the anatomy of deformity are presented and the probable causative factors are discussed. © 2003 Elsevier Science B.V. All rights reserved.
Article
The ontogeny and the effects of vertebral kyphosis on the mortality rate of reared sea bass (Dicentrarchus labrax) are described. The first evidence of deformities was observed in individuals of 10 mm total length (TL) in the form of light malformations or bilateral asymmetries of individual vertebrae. At 14 mm mean TL, the 18.2% of the reared fish...
Article
At four temperatures (T= 15, 20, 25 and 28° C) swimming performance of Dicentrarchus labrax was significantly correlated with total length (23–43 mm LT); r2=0.623–0.829). The relative critical swimming speed (RUcrit=UcritLT−1), where Ucrit is the critical swimming speed, was constant throughout the LT range studied. The significant effect of temper...
Article
The osteological development of vertebral column and fins in white sea bream, Diplodus sargus (Linnaeus, 1758) was studied. Vertebral ontogeny started at 5.7 mm total length (TL, post-fixation), with the formation of the first cartilaginous neural and haemal arches, and was completed by the full attainment of dorsal ribs (20.8 mm TL). The formation...
Article
We studied the ontogeny of Dicentrarchus labrax comparatively under constant rearing temperatures of 13, 15 and 20°C. At hatching, yolk-sac larval morphometry differed significantly between the temperatures and especially between the two extremes, while at the end of the yolk-sac larval stage, it mainly differed between the two lower temperature re...
Article
The influence of changes in environmental temperature on the mRNA levels of myogenic regulatory factors (MRFs), i.e. MyoD and myogenin, as well as myosin heavy chain (MyHC) were studied during early larval development in rainbow trout and sea bass. Phosphoimager analysis of northern blots indicated that there is an optimum temperature for the RNA t...
Article
The development of saddleback syndrome and of caudal fin deformities in Dentex dentex (Linnaeus, 1758) was compared under two rearing methods, extensive (E) and semi-extensive (S). The osteological appearance and the meristic characters of the reared fish were compared to that of D. dentex juveniles, collected from the natural environment. All the...
Article
The osteological development of dorsal, anal and paired fins and the squamation in common dentex, Dentexdentex (Linnaeus, 1758), was studied under extensive larval rearing conditions. The ontogeny of the fins was determined in three stages: (1) the yolk-sac and the early larval stage (up to 6.7 mm in vivo total length, TL), in which the majority of...
Article
A general description of the morphological modifications of the lateral line in gilthead sea bream, reared under hatchery conditions, is provided. Farm-reared fish were examined and compared to wild fish. We used the presence of a pore on the specialized scales of the lateral line to determine the density and distribution of associated sensory neur...
Article
To test the hypothesis that sex determination in the European sea bass (Dicentrarchus labrax L.) Can be affected by the incubating temperature during the very early developmental stages, eggs from the same batch of spontaneously spawned broodstock were divided at the stage of half-epiboly into three groups according to rearing temperature: G13 = 13...
Article
Sea bass and sea bream juveniles with functional swimbladder were exposed to three methods of preservation: (a) in 10% phosphate buffered formalin, (b) at 4°C, and (c) at −25°C. They were then X-rayed daily over 10 days to evaluate the impact of these methods on the evolution of the radiographic image. All methods significantly decreased the appare...
Article
The development of the skull skeleton in common dentex, Dentex dentex (Linnaeus, 1758), was studied under extensive rearing conditions. Skull ontogeny started after hatching and went through three stages: (a) the yolk-sac (during the phase of no growth) and the early larval stage (up to 6.9 mm in vivo total length, TL) in which the majority of the...
Article
The ontogeny of Dentex dentex (Linnaeus, 1758) was studied comparatively under extensive and semi-extensive rearing conditions. The exotrophic phase was divided into three distinct developmental stages (a) larval, from feeding onset up to 10 mm total length (TL); (b) metamorphosis, from 10 mm TL up to 24 mm TL; and (c) further juveniles. The majori...
Article
Osteological development of the vertebral column and caudal complex in common dentex was described under extensive larval rearing conditions. Generally, the cartilaginous bones developed prior to the membranous bones. The development of the axial skeleton began with the formation of the hypural 1, the neural arches 2 and 3, as well as the haemal ar...
Article
Hybridization between gilthead sea bream, Sparus aurata, and red porgy, Pagrus pagrus, was undertaken and viable hybrids were produced by an artificial hormonal-induced cross. The hybrids, from the cross of female red porgy and male gilthead sea bream (Pp Sa), survived through the yolk-sac larval stage. The hybrids produced from the cross of female...
Article
External morphology, head morphometry and osteology were used for early detection, description and heuristic study of the opercular complex abnormalities of intensively reared gilthead sea bream larvae (Sparus aurata). The first evidence of malformations were observed in larvae of 6.1 mm total length (TL). The abnormalities were fully developed dur...
Article
Lordosis in reared sea bass was previously related either to the absence of swimbladder, or to bad or late inflation of this organ when damages were irreversible. Our results prove that these explanations are insufficient and that similar deformations may occur frequently in fry with functional swimbladder during the early weaning phase, if current...
Article
Normal osteological development of the caudal fin in gilthead sea bream is described at the larval and juvenile stages. It was used as a standard for the study of a sea bream larval population with characteristic osteological deviations which give rise to abnormal juveniles. Normal specimens were reared under extensive rearing conditions, and abnor...