The Role of Melatonin to Ameliorate Oxidative Stress in Sperm Cells.

It is widely accepted that oxidative stress (OS) coming from a wide variety of causes has detrimental effects on male fertility. Antioxidants could have a significant role in the treatment of male infertility, and the current systematic review on the role of melatonin to ameliorate OS clearly shows that improvement of semen parameters follows melatonin supplementation. Although melatonin has considerable promise, further studies are needed to clarify its ability to preserve or restore semen quality under stress conditions in varied species. The present review examines the actions of melatonin via receptor subtypes and its function in the context of OS across male vertebrates.

Stalactites Core Prospect as Environmental "Microbial Ark": The Actinomycetota Diversity Paradigm, First Reported from a Greek Cave.

Speleothems found in caves worldwide are considered the natural libraries of paleontology. Bacteria found in these ecosystems are generally limited to Proteobacteria and Actinomycetota, but rare microbiome and "Dark Matter" is generally under-investigated and often neglected. This research article discusses, for the first time to our knowledge, the diachronic diversity of Actinomycetota entrapped inside a cave stalactite. The planet's environmental microbial community profile of different eras can be stored in these refugia (speleothems). These speleothems could be an environmental "Microbial Ark" storing rare microbiome and "Dark Matter" bacterial communities evermore.

High-Resolution Melting (HRM) Analysis for Rapid Molecular Identification of Sparidae Species in the Greek Fish Market.

The red porgy (Pagrus pagrus) and the common dentex (Dentex dentex) are Sparidae species of high commercial value, traded in the Greek market. In some cases, fish species identification from Greek fisheries is difficult for the consumer due to the strong morphological similarities with their imported counterparts or closely related species such as Pagrus major, Pagrus caeroleustictus, Dentex gibbosus and Pagellus erythrinus, especially when specimens are frozen, filleted or cooked. Techniques based on DNA sequencing, such as COI barcoding, accurately identify species substitution incidents; however, they are time consuming and expensive. In this study, regions of mtDNA were analyzed with RFLPs, multiplex PCR and HRM in order to develop a rapid method for species identification within the Sparidae family. HRM analysis of a 113 bp region of cytb and/or a 156 bp region of 16s could discriminate raw or cooked samples of P. pagrus and D. dentex from the aforementioned closely related species and P. pagrus specimens sampled in the Mediterranean Sea when compared to those fished in the eastern Atlantic. HRM analysis exhibited high accuracy and repeatability, revealing incidents of mislabeling. Multiple samples can be analyzed within three hours, rendering this method a useful tool in fish fraud monitoring.

Development of Multiplex PCR and Melt-Curve Analysis for the Molecular Identification of Four Species of the Mullidae Family, Available in the Market.

The authentication of food products and the verification of their identity are of major importance for consumers. Food fraud through mislabeling is an illegal practice consisting of the substitution of an expensive food product by a relatively cheaper one, misleading false labelling of their origin and adulteration in processed or frozen products. This issue is particularly of high importance concerning fish and seafood, which are easily adulterated primarily due to difficult morphological identification. Fish species of the Mullidae family are considered among the most high-valued seafood products traded in Greece and Eastern Mediterranean in general, in terms of the price and demand. Specifically, the red mullet (Mullus barbatus) and the striped red mullet (Mullus surmuletus) are both indigenous in the Aegean (FAO Division 37.3.1) and the Ionian (FAO Division 37.2.2) Seas, with high levels of consumers' preferences. However, they could be easily adulterated or misidentified by the invasive Aegean Sea Lessepsian migrator goldband goatfish (Upeneus moluccensis) as well as by the imported West African goatfish (Pseudupeneus prayensis). Keeping this in mind, we designed two novel, time-saving and easy-to-apply multiplex PCR assays and one multiple Melt-Curve analysis real-time PCR for the identification of these four species. These methodologies are based on species-specific primers targeting single nucleotide polymorphisms (SNPs) detected via sequencing analysis of the mitochondrial cytochrome C oxidase subunit I (CO1) and of the cytochrome b (CYTB) genes in newly collected individuals, with additional comparison with congeneric and conspecific haplotypes obtained from the GenBank database. Both methodologies, targeting CO1 or CYTB, utilize one common and four diagnostic primers, producing amplicons of different length that are easily and reliably separated on agarose gel electrophoresis, yielding a single clear band of diagnostic size for each species or a certain Melt-Curve profile. The applicability of this cost-effective and fast methodology was tested in 328 collected specimens, including 10 cooked samples obtained from restaurants. In the vast majority (327 out of the 328) of the specimens tested, one single band was produced, in agreement with the expected products with a single exception a M. barbatus sample that was identified as M. surmuletus, the identity of which was confirmed using sequencing, indicating erroneous morphological identification. The developed methodologies are expected to contribute to the detection of commercial fraud in fish authentication.

Microbiota profile of filleted gilthead seabream (Sparus aurata) during storage at various conditions by 16S rRNA metabarcoding analysis.

The aim of the present work was to study the microbiota profile of gilthead seabream (Sparus aurata) fillets stored either aerobically or under Modified Atmosphere Packaging (MAP) conditions at 0, 4, 8 and 12 °C, via 16S rRNA metabarcoding sequencing. Throughout storage, sensory assessment was also applied to estimate fillets' end of shelf-life. Results indicated that storage conditions strongly influenced the shelf-life of the fillets, since the sensorial attributes of air-stored samples deteriorated earlier than that of MAP-stored fillets, while higher temperatures also contributed to a more rapid products' end of shelf-life. Metataxonomic analysis indicated that Pseudomonas was by far the dominant genus at the end of fillet's shelf-life, in the vast majority of treatments, even though a sporadic but noteworthy presence of other genera (e.g, Shewanella, Carnobacterium, Brochothrix etc.) at the middle stages of MAP-stored fillets is also worth mentioning. On the other hand, a completely different profile as well as a more abundant bacterial diversity was observed at the end of shelf-life of MAP-stored fillets at 12 °C, in which Serratia was the most dominant bacterium, followed by Kluyvera, Hafnia, Rahnella and Raoultella, while Pseudomonas was detected in traces. The findings of the present work are very important, providing useful information about the spoilage status of gilthead seabream fillets during several storage conditions, triggering in parallel the need for further studies to enrich the current knowledge and help stakeholders develop innovative strategies that delay the growth of key spoiler players and consequently, retard spoilage course.

The use of various statistical methods for authenticity and detection of adulteration in fish and seafood.

Various methodologies including genetic analyses, morphometrics, proteomics, lipidomics, metabolomics, etc. are now used or being developed to authenticate fish and seafood. Such techniques usually lead to the generation of enormous amounts of data. The analysis and interpretation of this information can be particularly challenging. Statistical techniques are therefore commonly used to assist in analyzing these data, visualizing trends and differences and extracting conclusions. This review article aims at presenting and discussing statistical methods used in studies on fish and seafood authenticity and adulteration, allowing researchers to consider their options based on previous successes/failures but also offering some recommendations about the future of such techniques. Techniques such as PCA, AMOVA and FST statistics, that allow the differentiation of genetic groups, or techniques such as MANOVA that allow large data sets of morphometric characteristics or elemental differences to be analyzed are discussed. Furthermore, methods such as cluster analysis, DFA, CVA, CDA and heatmaps/Circos plots that allow samples to be differentiated based on their geographical origin are also reviewed and their advantages and disadvantages as found in past studies are given. Finally, mathematical simulations and modeling are presented in a detailed review of studies using them, together with their advantages and limitations.

The use of telomeric length as authenticity marker in fish and seafood - a new perspective in the detection of adulteration.

In this review we propose the use of telomeric length (TL) as an authenticity marker that could provide an alternative method for differentiating fish and seafood samples or detecting fraud. Considering the ever-growing number of incidents of economically motivated fish and seafood adulteration using even more sophisticated methods to overcome current authenticity markers, the need to identify novel authenticity markers becomes essential. The TL of fish and seafood depends on individual characteristics (e.g., sex, age) and the environmental stimuli (e.g., temperature, water quality) to which these are exposed. Hence, both wild marine and freshwater populations occupying different geographical origin habitats might differ substantially because of the environmental cues affecting them. Moreover, the implementation of various rearing practices in aquaculture, such as different levels of fish and seafood density and increased ambient noise combined with site-specific environmental cues could affect TL, providing regulatory authorities with valuable information by distinguishing wild from reared populations and organic from conventional ones. In the present review the effects of both the environmental conditions and individual characteristics on the telomeric stability of fish and seafood telomeres are discussed, suggesting TL as a potential prospect authenticity marker that could be used to prevent fish and seafood adulteration.

Biogeography pattern of the marine angiosperm Cymodocea nodosa in the eastern Mediterranean Sea related to the quaternary climatic changes.

We investigated the population dynamics of a highly clonal marine angiosperm, Cymodocea nodosa, in the eastern Mediterranean Sea, to identify the historical dynamics, demography, and connectivity of the species in the area. Eighteen microsatellite loci were used in conjunction with coalescent methods to investigate the genetic structure and demographic history of C. nodosa meadows. Approximate Bayesian computation (ABC) modeling was used to examine the pattern of divergence over time in the context of environmental change over the course of the Quaternary period. ABC analysis revealed an initial split of the C. nodosa populations between the north-western, northern, and north-eastern Aegean Sea during the Pleistocene epoch, followed by a more recent divergence of the north-western population and the central-western part of the Aegean Sea. According to the results, the most parsimonious historical scenario is that of a pervasive genetic signature of the effects of the drop in sea level during the Pleistocene epoch. This scenario supports the isolation of the north-western, north, and north-eastern area, and the subsequent recolonization after post-glaciation sea level rise that may explain the north-western differentiation as well present-day detected dispersion of C. nodosa.

The Protective Role of Melatonin in Sperm Cryopreservation of Farm Animals and Human: Lessons for Male Fish Cryopreservation.

Cryopreservation is a technique that offers various advantages, especially in fish, among others, that makes the reproduction of species easier through a constant supply of sperm, synchronization of the gamete availability of both sexes, storage of semen for genetic improvement programs, reduction in the cost by eliminating the need to maintain male broodstock, and conserving the gametes of endangered species. However, freezing and warming procedures for cryopreservation lead to a reduction in the quality and viability of cryopreserved sperm because of oxidative stress. For this reason, the enrichment of extender media with antioxidants is a common method of cryopreservation of the semen of several fish species. Recently, many studies have been published for the protective role of antioxidants and especially of melatonin on male fertility preservation both in farm animals and humans, demonstrating the beneficial effects of melatonin as a sperm cryoprotectant. On the other hand, very few studies were conducted using melatonin as an antioxidant in different male fish species for semen cryopreservation. We conclude that the use of moderate concentrations of melatonin are beneficial to semen preservation, and the mechanisms through which melatonin acts positively on spermatozoa need to be further investigated to establish improvement protocols for cryopreservation in fish species.

Responses of the Mediterranean seagrass Cymodocea nodosa to combined temperature and salinity stress at the ionomic, transcriptomic, ultrastructural and photosynthetic levels.

The Little Neptune grass Cymodocea nodosa is a key seagrass species in the Mediterranean Sea, forming extensive and patchy meadows in shallow coastal and transitional ecosystems. In such habitats, high temperatures and salinities, separately and in combination, can be significant stressors in the context of climate change, particularly during heatwave events, and seawater desalination plant effluents. Despite well-documented negative, macroscopic effects, the underlying cellular and molecular processes of the combined effects of increasing temperature and salinities have remained largely elusive in C. nodosa - which are addressed by the present study. High salinity and high temperature, alone and in combination, affected ion equilibrium in the plant cells. Non-synonymous mutations marked the transcriptomic response to salinity and temperature stress at loci related to osmotic stress. Cell structure, especially the nucleus, chloroplasts, mitochondria and organization of the MT cytoskeleton, was also altered. Both temperature and salinity stress negatively affected photosynthetic activity as evidenced by ΔF/Fm', following an antagonistic interaction type. Overall, this study showed that all biological levels investigated were strongly affected by temperature and salinity stress, however, with the latter having more severe effects. The results have implications for the operation of desalination plants and for assessing the impacts of marine heat waves.

First Report of Uncinaria hamiltoni in Orphan Eastern Mediterranean Monk Seal Pups in Greece and Its Clinical Significance.

The Mediterranean monk seal (Monachus monachus) is classified by the IUCN as "endangered," with a global population estimated to number fewer than 800 individuals. Our understanding of the biology and health status of the species is still limited, rendering every medical case a challenge for conservationists and veterinary clinicians. Although studying and managing disease in wild marine hosts is complex and challenging, studying and mitigating the effects of any disease to the Mediterranean monk seal is of utmost importance for conservation. The aim of this study was to document for the first time the presence of the hookworm Uncinaria hamiltoni in rehabilitated Mediterranean monk seal pups in Greece. A detailed examination protocol was followed for all pups that live-stranded over 30 years in 22 different locations, including physical, parasitological, and other examinations. Hookworms (adults and/or eggs) were detected in all the fecal samples, from all animals. Molecular identification using MtDNA (COI) and ribosomal DNA (D2/D3 28S and internal transcribed spacer [ITS] regions) identified the nematode species as Uncinaria hamiltoni. The clinical impacts and the benefits of anthelmintic treatment as a tool for the conservation management of the species are discussed.

Nutritional Quality of the European Spiny Lobster Palinurus elephas (J.C. Fabricius, 1787) (Achelata, Palinuridae) and the Non-Indigenous Northern Brown Shrimp Penaeus aztecus Ives, 1891 (Dendrobranchiata, Penaeidae).

The European spiny lobster is a species of great commercial value, yet a limited scientific knowledge exists on its biology, ecology, and physiology, especially for the stocks from east Mediterranean waters. The northern brown shrimp, a non-indigenous established species, is commercially exploited in regions of the Mediterranean Sea. Both species' proximate composition and fatty acid profile were assessed for the first time in the Mediterranean region, exhibiting an overall significant statistical difference. Protein, fat, and energy contents were significantly higher in the northern brown shrimp, whereas moisture and ash contents were significantly higher in the European spiny lobster. The proximate composition for both species was well within the reported range for other lobster and prawn species in the Mediterranean Sea.

Malpigmentation of Common Sole (Solea solea) during Metamorphosis Is Associated with Differential Synaptic-Related Gene Expression.

In farmed flatfish, such as common sole, color disturbances are common. Dyschromia is a general term that includes the color defects on the blind and ocular sides of the fish. The purpose was to examine the difference in gene expression between normal pigmented and juveniles who present ambicoloration. The analysis was carried out with next-generation sequencing techniques and de novo assembly of the transcriptome. Transcripts that showed significant differences (FDR < 0.05) in the expression between the two groups, were related to those of zebrafish (Danio rerio), functionally identified, and classified into categories of the gene ontology. The results revealed that ambicolorated juveniles exhibit a divergent function, mainly of the central nervous system at the synaptic level, as well as the ionic channels. The close association of chromophore cells with the growth of nerve cells and the nervous system was recorded. The pathway, glutamate binding-activation of AMPA and NMDA receptors-long-term stimulation of postsynaptic potential-LTP (long term potentiation)-plasticity of synapses, appears to be affected. In addition, the development of synapses also seems to be affected by the interaction of the LGI (leucine-rich glioma inactivated) protein family with the ADAM (a disintegrin and metalloprotease) ones.

The use of molecular markers in the verification of fish and seafood authenticity and the detection of adulteration.

The verification of authenticity and detection of food mislabeling are elements that have been of high importance for centuries. During the last few decades there has been an increasing consumer demand for the verification of food identity and the implementation of stricter controls around these matters. Fish and seafood are among the most easily adulterated foodstuffs mainly due to the significant alterations of the species' morphological characteristics that occur during the different types of processing, which render the visual identification of the animals impossible. Even simple processes, such as filleting remove very important morphological elements and suffice to prevent the visual identification of species in marketed products. Novel techniques have therefore been developed that allow identification of species, the differentiation between species and also the differentiation of individuals that belong to the same species but grow in different populations and regions. Molecular markers have been used during the last few decades to fulfill this purpose and several improvements have been implemented rendering their use applicable to a commercial scale. The reliability, accuracy, reproducibility, and time-and cost-effectiveness of these techniques allowed them to be established as routine methods in the industry and research institutes. This review article aims at presenting the most important molecular markers used for the authentication of fish and seafood. The most important techniques are described, and the results of numerous studies are outlined and discussed, allowing interested parties to easily access and compare information about several techniques and fish/seafood species.

The international initiatives of the collaboration between the Aristotle University of Thessaloniki School of Medicine, the Panhellenic Medical Association and the World Psychiatric Association, concerning mental health during the COVID-19 outbreak.

During the coronavirus disease 2019 (COVID-19) pandemic, all European countries were hit, but mortality rates were heterogenous, with some countries being hit very hard, while others including Greece had a much lower death rate during the first wave of spring 2020. The ultra-fast application of measures was probably the reason of this outstanding success. This outbreak is expected to trigger feelings of fear, worry, and stress, as responses to an extreme threat for the community and the individual. In addition, changes in social behavior, as well as in working conditions, daily habits and routine, are expected to impose further stress, especially with the expectation of an upcoming economic crisis and possible unemployment. In Greece, where the lockdown was extremely successful in terms of containing the outbreak, worries concerning the possible adverse effects on mental health were also predominant. A collaboration concerning mental health during the COVID-19 outbreak was established, between the Aristotle University School of Medicine, the Panhellenic Medical Association and the World Psychiatric Association. Two large multinational studies were launched, one concerning the general population and one university students. Students' mental health is an area of special interest, both because of the vulnerability of this age group as well as because any disruption during the time of the studies has profound long-term consequences in the lives of the individuals, and this might trigger feelings of fear, worry, and stress. According the results from the Greek arm of the students' study, during the lockdown, two-thirds of university students reported at least 'much' increase in anxiety, one third in depressive feelings and in 2.59% concerning suicidal thoughts. There was also a worsening of quality of life and deterioration of lifestyle issues. Major depression was present in 12.43% with an additional 13.46% experiencing severe distress. Beliefs in conspiracy theories enjoyed wide acceptance ranging from 20-68%, with students of law, literature, pedagogics, political sciences and related studies manifesting higher acceptance rates. Female sex and depression/dysphoria both independently but also in interaction were related to higher rates of such beliefs. The results of the Greek arm of the general population study suggested that during the lockdown, clinical depression was present in 9.31%, with an additional 8.5% experiencing severe distress. Increased anxious and depressive emotions (including subclinical cases) were present in more than 40% of the population. In persons with a previous history of depression, 23.31% experienced depression vs. 8.96% of cases without previous history, who were experiencing their first depressive episode. Family dynamics suggested that fewer conflicts and better quality of relationships were surprisingly related to higher anxiety and depressive emotions, higher rates of depression and distress, and greater rates of suicidal thoughts. Eventually, spiritual and religious affiliation could protect the individual from the emerging suicidal thoughts. As correlation does not imply causation, the results suggest that conspiracy theories could be either the cause of depression or on the contrary a coping mechanism against depression. After taking into consideration that also in the family environment the expression of anger seemed to be a protective factor, the most likely explanation could be that the beliefs in conspiracy theories are a coping and 'protective' mechanism against the emergence of depression. These studies were among the first published, they went deeper in the data collection and even led to the creation of a model with distinct stages for the development of mental disorders during the lockdown. The analysis of the international data will probably provide further insight into the prevalence of mental disorders and the universal but also culturally specific models and factors pertaining to their development. At the time this editorial was in press, more than 40 countries representing more than two thirds of earth's population were participating with more than 45,000 responses already gathered.

Correlation between intermediary metabolism, Hsp gene expression, and oxidative stress-related proteins in long-term thermal-stressed Mytilus galloprovincialis.

Long-term exposure of Mytilus galloprovincialis to temperatures beyond 26°C triggers mussel mortality. The present study aimed to integratively illustrate the correlation between intermediary metabolism, hsp gene expression, and oxidative stress-related proteins in long-term thermally stressed Mytilus galloprovincialis and whether they are affected by thermal stress magnitude and duration. We accordingly evaluated the gene expression profiles, in the posterior adductor muscle (PAM) and the mantle, concerning heat shock protein 70 and 90 (hsp70 and hsp90), and the antioxidant defense indicators Mn-SOD, Cu/Zn-SOD, catalase, glutathione S-transferase, and the metallothioneins mt-10 and mt-20. Moreover, we determined antioxidant enzyme activities, oxidative stress through lipid peroxidation, and activities of intermediary metabolism enzymes. The pattern of changes in relative mRNA expression levels indicate that mussels are able to sense thermal stress even when exposed to 22°C and before mussel mortality is initiated. Data indicate a close correlation between the magnitude and duration of thermal stress with lipid peroxidation levels and changes in the activity of antioxidant enzymes and the enzymes of intermediary metabolism. The gene expression and increase in the activities of antioxidant enzymes support a scenario, according to which exposure to 24°C might trigger reactive oxygen species (ROS) production, which is closely correlated with anaerobic metabolism under hypometabolic conditions. Increase and maintenance of oxidative stress in conjunction with energy balance disturbance seem to trigger mussel mortality after long-term exposure at temperatures beyond 26°C. Eventually, in the context of preparation for oxidative stress, certain hypotheses and models are suggested, integrating the several steps of cellular stress response.

Sex-specific impact of inbreeding on pathogen load in the striped dolphin.

The impact of inbreeding on fitness has been widely studied and provides consequential inference about adaptive potential and the impact on survival for reduced and fragmented natural populations. Correlations between heterozygosity and fitness are common in the literature, but they rarely inform about the likely mechanisms. Here, we investigate a pathology with a clear impact on health in striped dolphin hosts (a nematode infection that compromises lung function). Dolphins varied with respect to their parasite burden of this highly pathogenic lung nematode (Skrjabinalius guevarai). Genetic diversity revealed by high-resolution restriction-associated DNA (43 018 RADseq single nucleotide polymorphisms) analyses showed a clear association between heterozygosity and pathogen load, but only for female dolphins, for which the more heterozygous individuals had lower Sk. guevarai burden. One locus identified by RADseq was a strong outlier in association with parasite load (heterozygous in all uninfected females, homozygous for 94% of infected females), found in an intron of the citron rho-interacting serine/threonine kinase locus (associated with milk production in mammals). Allelic variation at the Class II major histocompatability complex DQB locus was also assessed and found to be associated with both regional variation and with pathogen load. Both sex specificity and the identification of associating functional loci provide insight into the mechanisms by which more inbred individuals may be more susceptible to the infection of this parasite. This provides important insight towards our understanding of the impact of inbreeding in natural populations, relevant to both evolutionary and practical conservation considerations.

Model-Based Distribution and Abundance of Three Delphinidae in the Mediterranean.

Monitoring of Delphinidae species population patterns in the Mediterranean Sea was carried out in a sequence of surveys employing different approaches. Data from seven-year surveys with small catamaran sailing boats were analyzed under model-based approaches. Density Surface Models were used to produce spatial distribution prediction of three Delphinidae species (Stenella coeruleoalba, Tursiops truncatus, and Delphinus delphis) in an extended study area covering much of the Mediterranean Sea. A classical distance sampling protocol was applied in order to calculate the detection probability of clusters. Static (depth, slope, distance from the coast, and distance from isobaths of 200 m) and nonstatic (sea surface temperature and chlorophyll) variables were used to predict the species distribution/abundance in a generalized additive model context. Stenella coeruleoalba was found to be the dominant species, with an extended distribution in the study area; its abundance was significantly affected by both depth and distance. Tursiops truncatus and Delphinus delphis illustrated a significant abundance correlation with depth and chlorophyll, respectively, while both species showed a robust longitude correlation. Our model pinpoints the significance of nondesigned transect line surveys, suggesting the importance of specific habitat areas for future monitoring and conservation aspects of marine mammals.

High Connectivity of the White Seabream (Diplodus sargus, L. 1758) in the Aegean Sea, Eastern Mediterranean Basin.

Population dynamics in the marine realm can shape species' spatial structure and genetic variability between given geographical areas. Connectivity is an important factor of species' population structure. In this study, we examined the genetic diversity and structure of white seabream (Diplodus sargus, L. 1758) in the eastern Mediterranean basin, using a panel of four microsatellite markers. Recorded low FST values within the study area indicate little evidence of genetic differentiation among populations. Results suggest high gene flow which may imply near-panmixia between populations, indicating the possibility of a probable movement of adult migrants, or strong passive drift at sea in early life stages of the species. To this extent, bibliographically speaking, different species within the Sparidae family favor altered population dynamics patterns with respect to local populations and genetic divergence, in the context of the molecular marker used.

Heterozygosity fitness correlations and generation interval of the Norway lobster in the Aegean Sea, eastern Mediterranean.

BACKGROUND: Comprehensively detailed information on population dynamics for benthic species is crucial since potential admixture of individuals could shift the genetic subdivision and age structure during a full breeding period. The apparent genetic impact of the potential recruitment strategy of Norway lobster Nephrops norvegicus is still under research. For this reason the present study was focused on genetic variation of the species over a given continuous year period in a semi-enclosed gulf of the Aegean Sea. RESULTS: Analyses revealed that the relative smaller size class in females and the apparent faster growth of males may represent a key-role differential strategy for the two sexes, whereas females tend to mature slower. Heterozygosity fitness correlations (HFCs) showed substantially significant associations suggesting that inbreeding depression for females and outbreeding depression for males are the proximate fitness mechanisms, respectively. CONCLUSIONS: Nephrops norvegicus uniformal genetic composition (background of high gene flow), could be attributed to potential population recolonization, due to a hypothesized passive larval movement from deeper waters, which may suggest that some offspring of local residents and potential male non-breeders from other regions admixture randomly.