Sparus Research Articles

Skeletal deformities in Sparus aurata from Türkiye: Incidences from Bafa Lake and the Aegean Sea

AbstractThe first record of the abnormalities ankylosis (fusion of vertebrae), lordosis (V‐shaped curvature of the vertebral column), kyphosis (Λ‐shaped curvature), and kypholordosis (the presence of both conditions) have been reported in two specimens of Sparus aurata collected from Bafa Lake and Bodrum‐Kıyıkışlacık Coast, Türkiye and used in this study. Both specimens displayed a severe level of deformity. All cases were non‐fatal as they occurred in subadult individuals. Assessment of abnormality in the studied specimen was carried out by the morphological diagnosis and using mammography. Externally, the two specimens have a deeper body than the normal specimen. There was significant osteological damage has been revealed by the mammography of these deformed specimens. The saddleback anomaly is in the anterior part of the spinous part of the dorsal fin that showed no missing spines. In addition, the lateral line was deformed in both specimens examined. In addition, there were several minor skeletal abnormalities. These anomalies have been considered an important indicator of environmentally induced stress on the wild fishes. Hence, the present finding highlights the need for closer monitoring of the marine environment and for the identification of the specific factor that causes these abnormalities.

Evaluating serum proteinogram methodologies for the diagnosis of inflammation in fish: Acute and chronic patterns in gilthead seabream (Sparus aurata) injected with λ-carrageenan.

Proteinogram is a semiquantitative method specially used in clinic to separate the serum proteins from patients for use in the diagnosis of diseases. However, this methodology has only been applied very recently with this approach in farmed fish. Thus, the aim of this study was to explore the changes in the serum proteinogram of gilthead seabream (Sparus aurata), after triggering an acute or chronic sterile inflammation. For this, two experiments were carried out: i) Acute inflammation experiment: seabream specimens were injected intramuscularly with 50μL of λ-carrageenan (0.5mg fish-1) or buffer (control) and blood samples were collected at 3, 6 and 24h post-injection; ii) Chronic inflammation experiment: specimens were injected at 0, 7 and 14 days with 500, 250 and 250μL of λ-carrageenan, respectively (20mg fish-1) or buffer, and blood samples were collected at 15 days post-injection. In both cases, serum was obtained and processed by electropherograms and HPLC-mass spectrometry. Results of electropherograms of control fish revealed four major proteins of 19.5, 76.3, 104.4, and 156.7kDa in the serum. These four proteins were correlated with apolipoprotein A-II (II (the counterpart of mammalian albumin, Apo fraction), serotransferrin (β fraction), inter-α-trypsin inhibitor heavy chain H3-like (α1 fraction) and α-2-macroglobulin-like (α2 fraction) according to the results obtained with HPLC-mass spectrometry. In a statistical view (p<0.05), no variations were detected in the four major serum protein bands between the control and the acutely inflamed groups. However, in chronically inflamed fish, the Apo fraction decreased statistically compared to the control group. In contrast, the α1 and α2 fractions were statistically increased in the serum of fish sampled 15 days after λ-carrageenan injection, compared to those found in the control fish. α1 and α2 protein fractions are recognized indicators of inflammation in mammals. Consequently, our study presents a novel method for assessing both acute and chronic λ-carrageenan-induced sterile inflammation in gilthead seabream, which could be applicable to other marine species for diagnostic purposes.

Photoperiod and Light Spectrum Modulate Daily Rhythms and Expression of Genes Involved in Cell Proliferation, DNA Repair, Apoptosis and Oxidative Stress in a Seabream Embryonic Stem Cell Line

The use of cell lines as alternative models for environmental physiology studies opens a new window of possibilities and is becoming an increasingly used tool in marine research to fulfil the 3R’s rule. In this study, an embryonic monoclonal stem cell line obtained from a marine teleost (gilthead seabream, Sparus aurata) was employed to assess the effects of photoperiod (light/dark cycles vs constant dark) and light spectrum (white, blue, green, blue/green and red lights) on gene expression and rhythms of cellular markers of proliferation, DNA repair, apoptosis and cellular/oxidative stress by RT-qPCR and cosinor analyses. The results obtained revealed the optimal performance of cells under blue light (LDB), with all the genes analysed showing their highest RNA expression levels and most robust daily variations/rhythms in this condition. Under LDB, the mRNA levels of cell proliferation (pcna), DNA repair (cry5), anti-apoptotic (bcl2) and oxidative stress (prdx2) markers peaked at the day-night transition, whereas pro-apoptotic (bax) and cell stress (hsp70) markers showed their highest expression at the night-day transition, evidencing the strong synchronisation of the transcription of key genes involved in the cell cycle in this photoregime. The persistence of significant pcna, cry5, hsp70 and prdx2 rhythms after 3 days in constant darkness reveals the endogenous and circadian nature of these rhythms. Our results highlight the importance of implementing photoperiods with light–dark cycles of blue wavelengths when performing fish cell culture research. These results reinforce and extend our previous studies, confirming the importance of lighting conditions that mimic the natural environment for the proper development of fish embryos and larvae in aquaculture.

Establishing the Physiological Values of Minimally Invasive Biomarkers in Gilthead Sea Bream (Sparus aurata)

Peripheral blood has been always used as the mirror of physiological status in a minimally invasive manner. In homeothermic vertebrates, different blood parameters have been correlated to a variety of biochemical and physiological processes and the establishment of physiological values have rendered them valuable indicators for research, diagnosis, and welfare status. Despite the volume of research in fish physiology and teleost significance for food security, information about the physiological values of minimally invasive biomarkers is still fragmented while there is a great need for such biomarkers for monitoring fish health, welfare, and factors that can impact their homeostasis. For the first time, we have focused on determining the physiological ranges of cholesterol, triglycerides, and total proteins in the plasma of gilthead sea bream (Sparus aurata) and detecting how size, diet, environment, and genetic background may influence these levels. A large heterogeneous dataset of 5318 healthy individuals of two different size classes (1–100 g; 101–200 g), dietary status (10 feeds and feeding regimes), and different genetic background (125 families), in combination with different geographic locations (GxE), was produced over a period of three years and analyzed to ensure a comprehensive representation in establishing the physiological range for these biomarkers. Dietary status and GxE introduced significant variations in the range of the physiological values of all biomarkers in both size classes. Triglyceride, total protein and cholesterol values did differentiate with age/size. Interestingly, all parameters responded to diet in a size-specific way, revealing their potential as biomarkers of dietary status.

Evaluation of the Sedative Effect of Limonene to Reduce Stress During Transportation of Gilthead Seabream (Sparus aurata)

Aquaculture practices often expose fish to several stressors, which may activate the stress system, decreasing welfare status and negatively affecting several physiological processes, such as growth, reproduction, or immune response [...]

Seasonal Changes in the Elemental Composition of Five Valuable Fish Species (Sparidae) from Bozcaada, North Aegean Sea: A Health Risk and Nutritional Benefit Assessment.

This study investigates the seasonal variations in the elemental composition of five economically valuable Sparidae fish species from Bozcaada, North Aegean: red seabream (Pagrus major), gilthead seabream (Sparus aurata), saddled seabream (Oblada melanura), white seabream (Diplodus sargus), and common dentex (Dentex dentex), with a focus on both essential minerals and toxic metals. Fish samples (n = 10 per species per season) were collected across four seasons, and their weights and lengths were recorded. The concentrations of elements such as calcium, potassium, magnesium, phosphorus, copper, iron, manganese, zinc, chromium, nickel, selenium, cadmium, and mercury were analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The elemental concentrations varied as follows: Ca (11,388.46-55,470.76), K (17,230.83-27,594.86), Mg (1436.02-2326.73), Na (1962.30-7847.41), P (13,112.11-15,516.57), Fe (107.61-282.00), Cu (36.44-59.13), Mn (6.19-19.87), Zn (98.67-256.26), Cr (4.54-11.96), Ni (6.33-13.89), Se (0.82-7.33), Cd (0.08-0.32), and Hg (0.08-1.50) mg/kg. Health risk assessments, including Estimated Weekly Intake (EWI), Target Hazard Quotient (THQ), and Cancer Risk (CR), were calculated for both adult and child consumers. The results showed that while the essential minerals remained within safe limits, seasonal variations in the concentrations of toxic metals could pose potential health risks, particularly with frequent consumption. This research provides valuable insights into balancing the nutritional benefits and safety of fish from Bozcaada, offering recommendations for informed consumption and public health policies aimed at optimizing benefits while minimizing risks.

PTR-ToF-MS VOC Profiling of Raw and Cooked Gilthead Sea Bream Fillet (Sparus aurata): Effect of Rearing System, Season, and Geographical Origin.

This study explores the impact of geographical origin, harvest time, and cooking on the volatile organic compound (VOC) profiles of wild and reared seabream from the Adriatic and Tyrrhenian Seas. A Proton Transfer Reaction-Time of Flight-Mass Spectrometry (PTR-ToF-MS) allowed for VOC profiling with high sensitivity and high throughput. A total of 227 mass peaks were identified. Principal component analysis (PCA) showed a clear separation between cooked and raw samples, with cooking causing a significant increase in 64% of VOCs, especially hydrogen sulphide, methanethiol, and butanal. A two-way ANOVA revealed significant effects of origin, time, and their interaction on VOC concentration, with 102 mass peaks varying significantly based on all three factors. Seasonal effects were also notable, particularly in reared fish from the Adriatic Sea, where compounds like monoterpenes and aromatics were higher during non-breeding months, likely due to environmental factors unique to that area. Differences between wild and reared fish were influenced by lipid content and seasonal changes, impacting the VOC profile of seabream. These findings provide valuable insights into how cooking, geographical origin, and seasonality interact to define the flavour profile of seabream, with potential applications in improving quality control and product differentiation in seafood production.

Fish protein hydrolysates from rainbow trout processing in replacement of feed protein sources: Effects on growth performances, liver status and body composition of gilthead sea bream, Sparus aurata L., juveniles

AbstractThe use of processing by‐products may reduce pressure on fish stocks as well as diminish wastes and negative environmental impact. Different studies investigated fish by‐products used as alternative nutritional source to conventional feedstuffs. Fish protein hydrolysates (FPH), as a protein source derived from discards of rainbow trout processing, were included in feeds and effects were evaluated on productive performances, liver status, and body composition in gilthead sea bream, Sparus aurata L., juveniles. Three groups of 170 juveniles each (initial weight 37.8 ± 0.5 g), in triplicate indoor tanks of 2 m3 volume each, were fed including FPH in L1 (7.5 g/kg) and L2 (15 g/kg) feeds in replacement of fishmeal. LC diet was used as control having fish meal and soybean meal as main protein sources. At the end of the trial (85 days), satisfactory productive performances were obtained in all the groups with similar performances. The final mean weight ranged from 76.6 to 78.0 g. The two FPH diets exhibited high palatability equal to LC. Liver histology did not differ although fat accumulation was detected in all fish. Body composition and fatty acids were similar. FPH as substitute of protein source is suitable in the feeding of gilthead sea bream juveniles.

Beyond Microbial Variability: Disclosing the Functional Redundancy of the Core Gut Microbiota of Farmed Gilthead Sea Bream from a Bayesian Network Perspective.

The significant microbiota variability represents a key feature that makes the full comprehension of the functional interaction between microbiota and the host an ongoing challenge. To overcome this limitation, in this study, fish intestinal microbiota was analyzed through a meta-analysis, identifying the core microbiota and constructing stochastic Bayesian network (BN) models with SAMBA. We combined three experiments performed with gilthead sea bream juveniles of the same hatchery batch, reared at the same season/location, and fed with diets enriched on processed animal proteins (PAP) and other alternative ingredients (NOPAP-PP, NOPAP-SCP). Microbiota data analysis disclosed a high individual taxonomic variability, a high functional homogeneity within trials and highlighted the importance of the core microbiota, clustering PAP and NOPAP fish microbiota composition. For both NOPAP and PAP BNs, >99% of the microbiota population were modelled, with a significant proportion of bacteria (55-69%) directly connected with the diet variable. Functional enrichment identified 11 relevant pathways expressed by different taxa across the different BNs, confirming the high metabolic plasticity and taxonomic heterogeneity. Altogether, these results reinforce the comprehension of the functional bacteria-host interactions and in the near future, allow the use of microbiota as a species-specific growth and welfare benchmark of livestock animals, and farmed fish in particular.

Bile Imprint on Parietal Peritoneum of Gilthead Seabream and Red Seabream: Effects of Fasting Duration, Stress, and Ice Storage

The Mediterranean aquaculture industry has recently been confronted with the appearance of a bile imprint on fish filets, which to-date remains of unknown etiology. This study investigates the involvement of common procedures applied before (fasting), during (confinement), and after (ice storage) fish harvesting. Two experiments were designed, one for gilthead seabream (Sparus aurata) and one for red seabream (Pagrus major). The fish were grouped according to fasting duration (1, 2, 3 days), harvesting method (stressed, unstressed), and ice storage (0 h, 48 h). In both species, the imprint appeared in all ice-stored fish for 48 h but not in fresh fish (0 h), the color of the imprint became darker as Days of Fasting increased, stressed fish had darker imprints than unstressed fish, and plasma and bile osmolality and cholesterol were significantly affected by treatments. The histological examination of the gallbladder in red seabream showed great variability in the muscularis thickness and appearance, regardless of treatment. These results are not conclusive as to the cause of the bile imprint appearance. However, they offer a first insight into an issue that bears significant impact in the marketing of aquaculture products and may foster further investigation in the search of the underlying causes of this reoccurring issue.

Response of Hard-Bottom Macro-Zoobenthos to the Transition of a Mediterranean Mariculture Fish Plant (Mar Grande of Taranto, Ionian Sea) into an Integrated Multi-Trophic Aquaculture (IMTA) System

: This study investigates the effects on hard-bottom macro-zoobenthic communities of converting a mariculture plant into an Integrated Multi-Trophic Aquaculture (IMTA) system. This study was conducted from 2018 to 2021 in the semi-enclosed Mar Grande basin of Taranto (northern Ionian Sea), on a facility located 600 m off the coastline, with a production capacity of 100 tons per year of seabass (Dicentrarchus labrax) and seabream (Sparus aurata). The results from seasonal sampling performed in a treatment site, where bioremediators (filter-feeding invertebrates such as sponges, polychaetes, mussels, and macroalgae) were deployed, and a control site without bioremediators were compared. Before the IMTA installation, the hard substrates under the cages were sparsely inhabited, with significant sediment coverage. By 2021, the treatment site exhibited revitalized and more diverse macro-zoobenthic communities, with species richness increasing from 83 taxa in 2018 to 104 taxa, including notable growth in sponges, annelids, mollusks, and bryozoans. In contrast, the control site showed no substantial changes in biodiversity over the same period. Biodiversity indices, including Shannon and Margalef indices, improved significantly at the treatment site, particularly during summer months, highlighting a more resilient and balanced benthic environment. Taxonomic distinctness (delta+) and multivariate analyses (PERMANOVA, PCO) confirmed significant spatial and temporal shifts in community structure at the treatment site, driven by IMTA implementation. SIMPER analysis identified key taxa contributing to these changes, which played a pivotal role in structuring the community. The emergence of filter feeders, predators, and omnivores at the treatment site suggests enhanced nutrient cycling and trophic complexity, while the decline in opportunistic species further supports improved environmental conditions. These findings demonstrate the potential of IMTA to promote recovery and sustainable mariculture practices, also offering a comprehensive understanding of its positive effects on hard-bottom benthic community dynamics.

Compositions of gilthead sea bream (Sparus aurata Linnaeus, 1758) from different culture systems

The aim of the present study was to investigate the effects of seasons (summer and winter) on the proximate, amino acid and fatty acid compositions of gilthead sea bream fish fed with commercial diets in sea cages and earthen ponds in the Aegean Sea in Türkiye. In general, the nutrient composition of the diets met the nutritional needs of the fish. Proximate analysis of fish fillets revealed that fish reared in earthen ponds had the lowest moisture and highest lipid content in the winter season (p < 0.05). Although fillet protein contents were comparatively higher in the winter (p < 0.05), there was no significant difference between systems in the same season (p > 0.05). Growing gilthead sea bream in marine cages produced fillets with high contents of the essential fatty acids (EFA) eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). On the other hand, the 18:1n-9 and 18:3n-3 contents of fish reared in earthen ponds increased by 25.64 and 18.80% respectively, compared to those in marine cages. Fillet content of total n-3 fatty acid were comparatively higher (p < 0.05) in gilthead sea bream from marine cages, and this increase was even more evident in the winter months. The n-3/n-6 ratios of fillets were significantly high in gilthead sea bream from marine cages in the summer. The levels of the essential amino acids (EAAs) arginine and leucine were higher in fillets from both systems in the winter. On the other hand, fillet contents of lysine were higher in the summer. In general, the total EAA content of fillets was higher in fish from the sea cages in summer. EAA/NEAA ratios in both systems in summer and winter were found to be at good levels in terms of fish fillet quality. Fillet contents of EFA and EAA from both systems and seasons were found to be good for human consumption and will have positive effects on human nutrition. In conclusion, commercial diets used in feeding gilthead sea bream improved the proximate, fatty acid and amino acid compositions of fillets to a good extent. Different seasons and culture systems may affect the nutritional composition of fish fillets, especially on fillet EFA contents. Results of fillet samples in marine cages and earthen ponds in summer and winter showed that the fish were of good quality for human health. Evaluation of the results in the present study shows that that gilthead sea bream can also be successfully cultured in earthen ponds in areas unsuitable for agriculture.

Jaw abnormalities may be lethal, recoverable, or stable during gilthead seabream growth

Jaw abnormalities may be lethal, recoverable, or stable during gilthead seabream growth

Erythrocytes from gilthead seabream (Sparus aurata) and European sea bass (Dicentrarchus labrax) did not engage in phagocytosis.

Phagocytosis is a fundamental innate immune process primarily executed by vertebrate leucocytes. Fish erythrocytes are involved in immune functions, although their role in phagocytosis remains poorly investigated. Consequently, this study aimed to examine the potential phagocytic mechanisms of fish erythrocytes. To this end, systemic blood erythrocytes were isolated from the teleost gilthead seabream (Sparus aurata) and European sea bass (Dicentrarchus labrax) and incubated for various times (20, 40, 60, 80, 100, and 120min) with formalin-inactivated bacteria or heat-killed yeasts labelled with fluorescein isothiocyanate. Their putative phagocytic properties and respiratory burst activity were investigated. Our results did not indicate variations in the phagocytic ability or phagocytic capacity of erythrocytes of seabream or sea bass incubated with the bacteria, whereas no activity was detected in the case of incubation with yeast. Additionally, no respiratory burst activity was detected in the erythrocytes of either fish species under any of the experimental conditions tested. Using fluorescence microscopy, it was observed that erythrocytes could bind bacteria to their surface membranes. However, this attachment process was rarely seen with yeast cells. In contrast, examination of the fine structure of erythrocytes using transmission electron microscopy showed distinctive inward and outward folding (pseudopodia formation) and some cytoplasmic vesicles in both species. The results of our study indicate that erythrocytes from gilthead seabream and sea bass did not exhibit phagocytic capabilities when exposed to these specific target particles. Additional studies are necessary to gain more insights into how they contribute to the immune system of fish.

Selection of Nonlethal Early Biomarkers to Predict Gilthead Seabream (Sparus aurata) Growth.

One of the main challenges in aquaculture is the constant search for sustainable alternative feed ingredients that can successfully replace fishmeal (FM) without any negative effects on fish growth and health. The goal of the present study was to develop a toolbox for rapidly anticipating the dynamics of fish growth following the introduction of a new feed; nonlethal, biochemical, and molecular markers that provide insights into physiological changes in the fish. A nutritional challenge by feeding a conventional feed rich in FM protein (FM diet) versus an experimental feed rich in plant protein (PP) and low FM inclusion (PP diet), in 20 different families of gilthead sea bream (Sparus aurata) was performed. Fifteen and 30 days after the initiation of the nutritional challenge, the transcriptional response of gilthead seabream erythrocytes along with classical hematological biochemical markers were compared. Zootechnical, biochemical, and transcriptome data from each family under different dietary treatments were combined into a classification model to identify variables that can predict the growth rate at the end of the 14-month farming period (July 2018-September 2019). A highly accurate model was produced (A > 80%) based on the combination of seven markers (five molecular and two biochemical markers) and with high potential in separating faster and slower growing fish as early as 30 days after the initiation of feeding.

Quality prediction of seabream (SPARUS AURATA) by DEEP learning algorithms and explainable artificial intelligence

Quality prediction of seabream (SPARUS AURATA) by DEEP learning algorithms and explainable artificial intelligence

Growth variability of selected Vibrio parahaemolyticus strains isolated from seafood

The aim of this study was to quantify the growth and assess the variability of V. parahaemolyticus strains isolated from seafood. A total of 35 V. parahaemolyticus strains were assessed, and their maximum specific growth rate (µmax) was estimated by the Time-to-Detection Method by regression analysis using the Generalized Reduced Gradient algorithm. The highest µmax (h-1) value was 2.33 for V. parahaemolyticus isolated from Atlantic salmon, followed by 2.30 for Mediterranean horse mackerel and European seabass, 2.26 for Mediterranean mussels, 2.20 for veined rapa whelk, 1.88 for the pandemic strain O3:K6, 1.57 for oysters, 1.43 for bluefish, and 1.29 for Gilthead bream. This study provides useful information for the quantitative characterisation of V. parahaemolyticus growth, which can be a main input for microbial exposure assessments.

Ability of short-chain fatty acids to reduce inflammation and attract leucocytes to the inflamed skin of gilthead seabream (Sparus aurata L.)

The aim of the study was to investigate the potential preventive use of short-chain fatty acids (SCFAs) to modulate inflammatory responses in gilthead seabream (Sparus aurata) skin. Initially, in vitro experiments were conducted to evaluate the effects of various concentrations of butyric acid, acetic acid and propionic acid, as well as their combination, on the cytotoxicity and cell viability of three different cell lines. The results determined the safe concentration of SCFAs, which was then used for an in vivo study. Fish were allocated into six groups and administered different combinations of SCFAs via intramuscular injection, followed by an injection of carrageenan as an inflammatory agent. Skin samples were taken from the injection site three hours post-administration and used to analyse gene expression and immunohistochemistry. The results demonstrated that treatment with SCFAs resulted in increased expression of proinflammatory and anti-inflammatory genes and leucocyte markers in the inflamed skin of fish. The highest gene expression and recruitment of acidophilic granulocytes were observed in fish injected with propionic acid and carrageenan. It is concluded that acetic acid is the most effective anti-inflammatory SCFA tested in gilthead seabream exposed to acute inflammation induced by carrageenan injection. Acetic acid exhibited the most pronounced direct anti-inflammatory effect, although propionic acid appeared to play a significant role in several mechanisms contributing to the resolution of inflammation and recruitment of immune cells to the site of carrageenan-inflamed area in gilthead seabream skin.

Enzymatic Hydrolysis Systems Enhance the Efficiency and Biological Properties of Hydrolysates from Frozen Fish Processing Co-Products.

Co-products from the frozen fish processing industry often lead to financial losses. Therefore, it is essential to transform these co-products into profitable goods. This study explores the production of fish protein hydrolysates (FPH) from three co-products: the heads and bones of black scabbardfish (Aphanopus carbo), the carcasses of gilthead seabream (Sparus aurata), and the trimmings of Nile perch (Lates niloticus). Four enzymatic hydrolysis systems were tested: an endopeptidase (Alcalase, A), an exopeptidase (Protana, P), two-stage hydrolysis with an endopeptidase followed by an exopeptidase (A + P), and a single stage with endo- and exopeptidase (AP). The results show that combined enzymatic treatments, especially single-stage Alcalase and Protana (AP), achieved high protein yields (80%) and enhanced degrees of hydrolysis (34 to 49%), producing peptides with lower molecular weights. FPH exhibited significant antioxidant activity, in 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, with EC50 values below 5 mg/mL. Additionally, AP hydrolysates demonstrated over 60% angiotensin-converting enzyme (ACE) inhibition at 5 mg/mL, indicating potential antihypertensive applications. Antidiabetic and anti-Alzheimer activities were present, but at relatively low levels. AP hydrolysates, especially from gilthead seabream, proved to be the most promising. This study highlights the value of fish co-products as sources of functional peptides, contributing to waste reduction, and their potential applications in food, agriculture, and nutraceuticals.

Impact of environmental factors on population dynamics and some biological aspects of the gilthead seabream (Sparus aurata) in Bardawill lagoon, North Sinai, Egypt

Impact of environmental factors on population dynamics and some biological aspects of the gilthead seabream (Sparus aurata) in Bardawill lagoon, North Sinai, Egypt