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Integrative studies on intraspecific differences of digestive enzymes, energy reserves, and morphological/somatic traits in juveniles and adults of estuarine-dependent marine fish while inhabiting inside a coastal lagoon are lacking. This study was carried on juveniles and adults of Mugil liza Valenciennes, 1836 inhabiting inside Mar Chiquita Coastal Lagoon (Argentina). Both stages exhibited amylase, maltase, sucrase, lipase, trypsin, and aminopeptidase-N activities in the intestine, which were active over a wide range of pH and temperatures and exhibited Michaelis–Menten kinetics. Adults exhibited higher intestinal coefficient (31%), higher amylase (32%), and lower maltase (82%) and lipase activities (38%). Glycogen concentration in liver and muscle was similar, while free glucose concentration was higher in adults (772% and 400%, respectively). In adults, retroperitoneal fat (absent in juveniles) constituted the main triglycerides (TAG) storage site, while TAG concentration in liver and muscle was lower (86% and 80%, respectively) than that in juveniles. No differences were found in protein concentration in any storage organ. The results show that juveniles and adults exhibit a digestive and metabolic profile at the biochemical level and intraspecific differences in key components of carbohydrate and lipid metabolism that could support preparation for reproductive migration of adults outside the coastal lagoon. [ABSTRACT FROM AUTHOR]

Rare earth elements are essential for modern life, although they are also classified as emerging pollutants. Currently, fish studies on these elements are very limited in general, but, with regard to the Caspian Sea, there is no reference to them at all. For this reason, our objective was to determine the concentrations of these elements in the golden grey mullet (Chelon auratus) and to contrast its bioaccumulation patterns with those of arsenic, cadmium, mercury and lead. For that purpose, 20 fish were caught in the southern part of the Caspian Sea. Heavy rare earth element concentrations were higher than light ones and the terbium levels were very high, probably due to anthropogenic contamination. The intestine tissue gave the highest concentrations, which could be indicative of a very low gastrointestinal absorption. For both rare earth and trace elements, muscle was the tissue that accumulated the least, despite which, cadmium and lead levels in muscle were of concern. [ABSTRACT FROM AUTHOR]

The present study aimed to investigate the characteristics in gill histology and ultrastructure of the flathead grey mullet, Mugil cephalus; as well as to compare between these structures in fish specimens inhabiting waters with different salinities. Fish specimens of M. cephalus were collected from Great bitter Lake at Ismailia Governorate (salinity: 38-45‰) and Bardawil Lagoon at Al-Arish, North Sinai Governorate (Salinity: 64-68 ‰). Histological examination showed that the chloride cells in gills of M. cephalus inhabiting marine waters (Great Bitter Lake) are located within the epithelium of the inter-lamellar regions and secondary lamellae; but in hyper saline waters (Bardawil Lagoon) fishes, chloride cells are located only within the primary epithelium of the inter-lamellar regions. The flat elongated pavement cells of secondary lamellar epithelium in marine fishes are more flattened than that in hypersaline water fishes. In each epithelium of the two opposite sides of secondary lamellae, two layers of cells were observed in hypersaline specimens, in which they overlap and interdigitate in a complex manner; but in marine specimens, only one layer of pavement cells was observed. The ultrastructure examination showed that chloride cells in specimens of marine water are large; ovoid or rounded in shape with a rich population of mitochondria. While, chloride cells in fishes inhabited hypersaline water displayed more rich populations of mitochondria. In the present study, statistical analysis to gill morphometric characteristic counts and measurements of gills in M. cephalus inhabiting marine water and hypersaline water revealed that there are statistically significant differences between these groups for most counts and measurements as well as their ratios. [ABSTRACT FROM AUTHOR]

The aim of this study was to monitor quality changes and estimate the shelf-life of the thicklip grey mullet (Chelon labrosus), a candidate species for the diversification of the world aquaculture production, during ice storage. Differences in shelf-life, microbial populations and TVB-N values were observed for fish caught in different months, but proximate composition did not differ between months. Based on sensory attributes, the shelf-life was 7 and 8 days for fish caught in October and December, respectively, when the APC was ca. 7.5–8.0 logs and Pseudomonas and/or H2S producing bacteria was 7.0–7.5 logs. TVB-N did not exceed 22 mg per 100 g throughout the storage. The moisture ranged from 73.7% to 78.3%, the protein content from 20.5% to 24.9%, the lipid content from 0.29% to 1.42% and the gross energy from 4.86 to 5.91 kJ g−1 of wet weight. Overall, this study provides stakeholders useful information for the quality of this fish species, contributing to food and nutritional security. [ABSTRACT FROM AUTHOR]

Different groups parasitize the gills of fishes, and the organisms can interact in positive, negative, or neutral ways, depending on parasitic abundance, environmental conditions, and the availability of resources. Here, we studied the distribution of ectoparasites on the gills of the mullet Mugil curema in the Cabedelo port region (Brazil), asking if (1) the gill parasites of M. curema fix on specific host gill arches and/or (2) co-occur in the same gill arches within a host individual; (3) if the abundance of one parasite taxon affects the abundance of another on the same gill arches; and (4) considering distinct major groups, if parasites present patterns of co-occurrence on hosts and gill arches different from the expected at random. We used generalized linear models, generalized linear mixed models, and models with zero inflation to define the microhabitats (arches) with the highest abundances of parasites and null models to analyze the co-occurrences of gill parasite groups. Three taxa of Monogenea (Ligophorus brasiliensis Abdallah, Azevedo & Luque, 2009, Ligophorus sp. 1 and Ligophorus sp. 2) and six species of Copepoda were recorded (Bomolochus nitidus Wilson, 1911; Caligus praetextus Bere, 1936; Ergasilus atafonensis Amado & Rocha, 1997; Ergasilus bahiensis Amado & Rocha, 1997; Ergasilus caraguatatubensis Amado & Rocha, 1997 and Ergasilus lizae Krøyer, 1863). We found that, in general, the gill parasites were more abundant/prevalent on specific arches (I and II) of the hosts, shared such preferences and co-occurred on the gill arches. The presence of one taxon influenced the occurrence of another only in the arches I and II; as a result, the infracommunities were characterized as interactive in the gills of this host species. [ABSTRACT FROM AUTHOR]

The objective of the present study was to explain the histological variations in the pyloric caeca and anterior intestine of Chelon ramada. For this purpose, small pieces of the target organs were attained from specimens of C. ramada: for histological and histochemical procedures. The final sections were examined under a microscope, photographed and described. Histologically, serosa, muscularis, submucosa, and mucosae are the main layers of the wall of pyloric caeca and anterior intestine in C. ramada indicating there are no remarkable differences in the basic structure. The mucosal folds of pyloric caeca are thin and deeply folded in a narrow lumen; in contrast, the mucosal folds of the anterior intestine are long protruding at a wide lumen. The mucosal layer of the anterior intestine is consisted of columnar and mucus cells as in the pyloric caeca, but mucous cells are numerous in number at the anterior intestine while it observed in fewer numbers at the mucosal layer of the pyloric caeca. In submucosal and mucosal layers, wandering cells and lymphocytes are plentiful especially among the columnar cells of the anterior intestine. These cells are more abundant in the anterior intestine than that observed in pyloric caeca; in contrast with the number of blood vessels. The present study concluded that the distribution and secretions of the mucosa are very clear with histochemical stains. This study is helpful for understanding the digestive physiology and the related functional mechanisms of fish digestion. [ABSTRACT FROM AUTHOR]

An analytical method for the simultaneous determination of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) in fish, shellfish and muscle of terrestrial animals was developed as an extension of a previously validated method for PBDE analysis. A single sample preparation based on QuEChERS-like extraction and a two-step clean-up, followed by a dual instrumental detection, was implemented. GC-MS/MS was used for PBDEs and LC-MS/MS for HBCDs. The method allows the quantification of fifteen PBDEs (28, 47, 49, 66, 77, 85, 99, 100, 138, 153, 154, 183, 197, 206, 209) and three HBCD isomers (α, β and γ), reaching 10 pg/g LOQs for all the analytes except BDE 206 and 209 (100 pg/g LOQ). The validated method was applied to the analysis of 12 fish and shellfish species (sole, spiny dogfish, smooth-hound, mackerel, swordfish, grey mullet, cod, anchovy, red mullet, Atlantic horse mackerel, tuna fish and mussel) collected in central Italian markets accounting for a total of 44 samples. Generally, ΣPBDEs showed higher concentration than ΣHBCDs except in the case of mussels in which ΣHBCDs > ΣPBDEs. Cod and smooth-hound are the least contaminated species among those analysed in the present study, whereas the highest brominated flame retardant (BFR) levels were found in spiny dogfish samples. The measured contamination levels were generally comparable to or lower than those already published in European studies. Literature data for HBCDs in European fish and shellfish were hard to find; therefore, PBDE and HBCD levels were also compared with European Environmental Quality Standard (EQS) in biota (Directive 2013/39/EU). EQSs for HBCDs are six orders of magnitude higher than those for PBDEs; therefore, while no exceedance was observed for the first, almost all the samples analysed for PBDEs were above EQSs. The presented preliminary data on PBDEs and HBCDs are among the first published in marine fish and shellfish commercialised in Central Italy. [ABSTRACT FROM AUTHOR]

This study documents the effect of cryopreservation on motility, DNA integrity, and gene expression in Mugil cephalus sperm. Fresh sperm were cryopreserved using V2 extender (V2E) or 0.3 M glucose, each in combination with one of three cryoprotective agents (CPAs), i.e., 10 % of dimethylsulfoxide, ethylene glycol, or glycerol, all at once. After two different storage (7- vs 60- day) periods in liquid nitrogen, sperm samples were thawed. Single-cell gel electrophoresis was used to detect the DNA integrity. Heat shock proteins (HSPs), HSP70 , HSP90 and glutathione peroxidase (GPx2) genes mRNA expression levels was documented using qRT-PCR. The results demonstrated that among 0.3 M glucose + CPAs combinations, EG recorded higher frozen-thawed motility 69 % (7- day) and 59 % (60- day). Similarly, in V2E + CPAs combinations, EG recorded higher frozen-thawed motility 31 % (7- day) and 26 % (60- day). The DNA integrity of all thawed sperm (both periods) did not differ from that of fresh sperm. The qRT-PCR results revealed that in the combination of 0.3 M glucose + CPAs, the level of HSP90 and GPx2 gene expression was found to be upregulated in frozen-thawed sperm on both periods. Whereas, the expression level of the HSP70 gene was down-regulated. On the contrary, in the combination of V2E + CPAs, the expression levels of HSP70 , HSP90 and GPx2 genes could not be detected on both periods. Overall, the findings of this study demonstrate that the cryomedium (extender + cryoprotectant) has a more influential role in the motility and levels of gene expression in the frozen-thawed sperm of M. cephalus. • The cryopreservation had a significant effect on frozen-thawed sperm motility. • The freezing-thawing process had no impact on the DNA integrity of sperm. • The cryomedium composition influences the expression level of genes in post-thaw sperm. [ABSTRACT FROM AUTHOR]

• UV filters (organic and mineral) disturbed skin and gut microbiome of grey mullets. • The skin microbiota was severely modified by UV filters exposure. • UV filters exposure allowed to pathogens bacteria to colonize the skin mucus of fish. • The skin microbiota of fish is better suitable for study environmental factor. UV filters (organic or mineral) present in sunscreen products are emerging contaminants of coastal aquatic environments. There is an urgent need to understand marine organisms responses to these compounds. In this study, we investigated the effect of exposure to dilutions of commercial sunscreen formulations on bacterial communities of mullet (Chelon sp.). The gut and skin mucus microbial communities were characterized using a metabarcoding approach targeting the 16S rRNA gene. Our results revealed that mullets had its own bacterial communities that differ from their surrounding habitats and specific to tissue. The dilutions of commercial sunscreens modified the relative abundance of Actinobacteroita, Bacteriodota and Proteobacteria for both gut and skin microbiota. They also allowed to bacteria affiliated to Mycobacterium, Nocardia and Tenacibaculum genera, known to house pathogenic species, to colonize the epithelium which may have implications for fish host health. [ABSTRACT FROM AUTHOR]

Neori, A.; Guttman, L.; Israel, A., and Shpigel, M., 2019. Israeli-developed models of marine integrated multi trophic aquaculture (IMTA). In: Jithendran, K.P.; Saraswathy, R.; Balasubramanian, C.P.; Kumaraguru Vasagam, K.P.; Jayasankar, V.; Raghavan, R.; Alavandi, S.V., and Vijayan, K.K. (eds.), BRAQCON 2019: World Brackishwater Aquaculture Conference. Journal of Coastal Research, Special Issue No. 86, pp. 11–20. Coconut Creek (Florida), ISSN 0749-0208. Modern Israeli integrated multi-trophic aquaculture (IMTA) has emerged from the Israeli freshwater polyculture, with carps, tilapia and grey mullet that started in the 1940-1950s. The dynamics, processes, environment and management of semi-intensive (several tons ha-1 y-1) mariculture IMTA started in the early 1970s, at the National Center for Mariculture (NCM) in Eilat, with several models that combined flow-through and recirculation features between primary (fed) and secondary (extractive) species. The seawater fishponds differed from freshwater ponds mainly in the continuous exchange with water from the open sea, to stabilize salinity and other water quality features. The primary (fed) fish was mostly the seabream (Sparus aurata), seabass (Dicentrarchus labrax), shrimp (Penaeus semisulcatus) and mullets (Mugil cephalus and Liza ramada). At first, the extractive component included microalgae, oysters (Crassostrea gigas) and clams (Ruditapes philippnmarum). In more progressive models, plastic-lined double drain ponds and tanks are used. Several other species, for example: clams, seaweed (the macroalgae Ulva spp. and Gracilaria spp.), abalone (Haliotis tuberculata and H. discus hannai), sea urchins (Paracentrotus lividus and Tripneustes gratilla elatensis), shrimp, brine shrimp (Artemia salina) are used. Wetlands planted with the halophytes Salicornia sp. and Sarcocrnia sp. have been integrated as IMTA. Recently, periphyton and drip-irrigated algal biofilters were examined and found to be practical. The research contributed to the enhancement of the sustainability, flexibility and potential for profitability of the aquaculture operation, based on the accumulated understanding about the functioning of the different units and the interactions between them. The principles developed in this research are relevant to brackishwater aquaculture, and have been applied for shrimp culture, mainly in China. [ABSTRACT FROM AUTHOR]

Gray mullet (Mugilidae) occur in all seas and are farmed widely around the world, and thus, the risk of their parasites spreading through transport of aquaculture seed is a serious concern. Among others, gray mullets typically host a diversity of myxosporeans, a group in which spore morphometrics of genera has been consistently shown to be inadequate for determination of species. In this study, we investigated Myxobolus Bütschli 1882 (Myxosporea) species found in two fingerling stocks of Mugil cephalus caught in the wild off the coasts of the eastern (Israel) and western (Spain) Mediterranean. Although we observed similar morphological features, significant dissimilarities in spore size and differences in Myxobolus species SSU rDNA sequences were noted. Genetic analyses demonstrated that multiple Myxobolus species, some with SSU rDNA sequences new to GenBank, infected the stock from Spain. In addition, Myxobolus DNA was found associated with several types of host tissue (gill, tail, and internal organs), and sequence analyses indicated that multiple species of Myxobolus were also present, sometimes in different tissues from the same fish. The results suggest that the gray mullets supported a collection of several different Myxobolus species with similar morphology. [ABSTRACT FROM AUTHOR]

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Some commonly consumed marine fish species are considered to display a higher risk of bio-accumulating organic environmental contaminants such as PBDEs. As part of a study to investigate the spatial distribution of these contaminants, data on polybrominated diphenlyethers (PBDEs) and polybrominated biphenyls (PBBs) were collected and analysed by introducing a web-based resource which enables efficient spatial, species and concentration level representations. Furthermore, hierarchical cluster analyses permits correlations within the data to be predicted. The data provide current information on levels of PBDE and PBB occurrence, allowing identification of locations that show higher contaminant levels. 135 fish samples of various species were analysed from UK marine waters, but encompassing the waters around Norway in the North and to the Algarve in the South. PBDEs were observed in all samples with the majority of measured congeners being detected. The concentrations ranged from 0.087 μg/kg to 8.907 μg/kg whole weight (ww) for the sum of all measured PBDE congeners. PBBs occurred less frequently showing a corresponding range of <0.02 μg/kg to 0.97 μg/kg ww for the sum of seven PBB congeners. Concentrations vary depending on species and locations where landed, e.g. PBBs occurred more frequently and at higher levels in grey mullet from French waters. The high frequency of PBDE occurrence makes it prudent to continue the monitoring of these commonly consumed marine fish species. The web-based resource provides a flexible and efficient tool for assessors and policy-makers to monitor and evaluate levels within caught fish species improving evidenced-based decision processes. [ABSTRACT FROM AUTHOR]

Intersex gonads have been observed in thicklip grey mullet Chelon labrosus , inhabiting estuaries with high burdens of xenoestrogens in the Southeast Bay of Biscay, but knowledge of population connectivity among estuaries is lacking for this euryhaline fish species. This study investigates the population structure of C. labrosus using otolith shape and elemental signatures of 60 adults (overall length ∼ 38 cm) from two estuaries 21 nautic miles apart, one with a high incidence of intersex condition (Gernika), and the other one pristine (Plentzia). Otolith shape analyses were performed using elliptical Fourier descriptors, while elemental signatures of whole sagittae were obtained by inductively coupled plasma mass spectrophotometry. Univariate and multivariate statistics were applied to determine if otolith signatures show patterns of homogeneity between estuaries. The data indicated significant differences in the otolith shape and elemental composition between mullets of Gernika and Plentzia. Elemental differences were mainly driven by Sr, Li (both higher in Plentzia) and Ba (higher in Gernika). The 98% re-classification success rate obtained from stepwise linear discriminant function analysis suggests that Gernika and Plentzia individuals form separated population units. The limited connectivity between these two close estuaries would indicate a different life history of exposure to chemicals, which might explain the high prevalence of intersex condition in Gernika and its absence in Plenztia. • Population connectivity was studied in Chelon labrosus from two Basque estuaries. • Otolith shape and composition were studied to understand population structure. • Mullets from Gernika and Plentzia showed significant differences in otolith shape. • Significant differences in Sr, Li and Ba were found in otoliths of both estuaries. • Thicklip grey mullets form separated population units in two nearby estuaries. [ABSTRACT FROM AUTHOR]

Over the last decade, xenoestrogenic effects have been reported in populations of thicklip grey mullet Chelon labrosus from contaminated estuaries in the Bay of Biscay, resulting in intersex condition. To understand the level of gene flow in individuals of different Basque estuaries microsatellite markers were used to evaluate the population structure and connectivity of C. labrosus from estuaries of the Basque coast. 46 microsatellites were tested and 10 validated for the analysis of 204 individuals collected from 5 selected Basque estuaries and 2 outgroups in the Bay of Cadiz and Thermaic Gulf. The polymorphic microsatellites revealed 74 total alleles, 2–19 alleles per locus. The mean observed heterozygosity (0.49 ± 0.02) was lower than the expected one (0.53 ± 0.01). There was no evidence of genetic differentiation (F ST = 0.0098, P = 0.0000) among individuals or sites. Bayesian clustering analysis revealed a single population in all sampled locations. The results of this study indicate widespread genetic homogeneity and panmixia of C. labrosus across the current sampling areas spanning the Atlantic and Mediterranean basins. The hypothesis of panmixia could therefore be well supported so individuals inhabiting estuaries with high prevalence of intersex condition should be considered as members of the same single genetic group as those inhabiting adjacent estuaries without incidence of xenoestrogenicity. • The genetic structure of Chelon labrosus in Basque estuaries was studied. • Microsatellites show panmixia in estuaries with different degree of xenostrogenicity • Genetic homogeneity and panmixia is observed from the Atlantic to the Mediterranean. • Absence of genetic partitioning was due to high levels of dispersal and gene flow. • Basque estuaries do not house genetically isolated mullet populations. [ABSTRACT FROM AUTHOR]

The White and Striped mullets (Mugil curemaandM. cephalus)are highly abundant and commercially important estuarine fish in northwest (NW) Mexico. Because of their feeding habits and habitat, they are likely to accumulate mercury (Hg) in their muscle and liver. The objectives of this study were to determine total Hg distribution in the tissues of interest, to correlate Hg levels between tissues and with length and weight of fish, to estimate the percentage weekly intake (PWI) of total Hg and methyl Hg (MeHg) through consumption of both mullet species, and to compare total Hg levels with mullets from other areas. The highest total Hg concentration (1.031 µg g−1dry weight) was measured in liver of White mullet. In both species, the order of averaged Hg concentrations (M. curemaliver 0.272, muscle 0.184;M. cephalusliver 0.211, muscle 0.129 µg g−1dry weight) were liver>muscle. Correlations of Hg in muscle and liver with total weight ofM. curemawere significant. InM. cephalus, Hg levels in liver were significantly correlated with total length and weight. The PWI of THg (<4%) and MeHg (<10%) were not elevated for both species. Concentration of Hg in the studied mullets was comparable to levels in similar species from Mexican waters but lower than results in mugilids from other coastal areas. [ABSTRACT FROM PUBLISHER]

The grey mullet usually occur in large numbers and biomass in the estuaries of all three South African biogeographic regions, thus making it an ideal family to use in terms of possibly acting as an environmental indicator of global warming. In this analysis the relative estuarine abundance of the dominant three groups of mugilids, namely tropical, warm-water and cool-water endemics, were related to sea surface coastal temperatures. The study suggests a strong link between temperature and the distribution and abundance of the three mullet groups within estuaries and indicates the potential of this family to act as an indicator for future climate change within these systems and adjacent coastal waters. [ABSTRACT FROM AUTHOR]

Mercury (Hg) is recognized as a dangerous contaminant due to its bioaccumulation and biomagnification within trophic levels, leading to serious health risks to aquatic biota. Therefore, there is an urgent need to unravel the mechanisms underlying the toxicity of Hg. To this aim, a metabolomics approach based on protonic nuclear magnetic resonance ( 1 H NMR), coupled with chemometrics, was performed on the gills of wild golden grey mullets L. aurata living in an Hg-polluted area in Ria de Aveiro (Portugal). Gills were selected as target organ due to their direct and continuous interaction with the surrounding environment. As a consequence of accumulated inorganic Hg and methylmercury, severe changes in the gill metabolome were observed, indicating a compromised health status of mullets. Numerous metabolites, i.e. amino acids, osmolytes, carbohydrates, and nucleotides, were identified as potential biomarkers of Hg toxicity in fish gills. Specifically, decrease of taurine and glycerophosphocholine, along with increased creatine level, suggested Hg interference with the ion-osmoregulatory processes. The rise of lactate indicated anaerobic metabolism enhancement. Moreover, the increased levels of amino acids suggested the occurrence of protein catabolism, further supported by the augmented alanine, involved in nitrogenous waste excretion. Increased level of isobutyrate, a marker of anoxia, was suggestive of onset of hypoxic stress at the Hg contaminated site. Moreover, the concomitant reduction in glycerophosphocholine and phosphocholine reflected the occurrence of membrane repair processes. Finally, perturbation in antioxidant defence system was revealed by the depletion in glutathione and its constituent amino acids. All these data were also compared to the differential Hg-induced metabolic responses previously observed in liver of the same mullets (Brandão et al., 2015). Overall, the environmental metabolomics approach demonstrated its effectiveness in the evaluation of Hg toxicity mechanisms in wild fish under realistic environmental conditions, uncovering tissue-specificities regarding Hg toxic effects namely in gills and liver. [ABSTRACT FROM AUTHOR]

Abstract: Endocrine disrupting chemicals (EDCs) interfere with the functioning of the endocrine system, causing reproductive and developmental disturbances in aquatic wildlife. Appearance of intersex gonads and elevated plasma levels of vitellogenin in male fish are well known biomarkers of exposure to xenoestrogenic EDCs. In the present study, intersex condition and transcription levels of vtg and cyp19a1b were assessed in five thicklip grey mullet populations from the Basque coast (Bay of Biscay). Levels of EDCs (estrogenic hormones, polycyclic musks, bisphenol-A, phthalates, alkylphenols and pesticides) were determined in water and fish bile. Intersex gonads were observed in three out of five mullet populations. Vtg and cyp19a1b were up-regulated in mullet populations with relatively higher EDCs load. Phthalates and pesticides were the most abundant EDCs in bile, followed by alkylphenols, musks, bisphenol-A and estrogenic hormones. Statistically significant correlations were found between concentrations of individual and total EDCs in bile and water samples and transcription levels of vtg and cyp19a1b. [Copyright &y& Elsevier]

Fish are bioindicators of water pollution, and an increased rate of their erythrocyte nuclear morphological abnormalities (ENMAs)-and particularly of erythrocyte micronuclei (EMN)-is used as a genotoxicity biomarker. Despite the potential value of ENMAs and MN, there is scarce information about fish captured in Iberian estuaries. This is the case of the Portuguese estuaries of the Mondego, Douro and Ave, suffering from different levels of environmental stress and where chemical surveys have been disclosing significant amounts of certain pollutants. So, the aim of this study was to evaluate genotoxicants impacts and infer about the exposure at those ecosystems, using the grey mullet ( Mugil cephalus) as bioindicator and considering the type and frequency of nuclear abnormalities of erythrocytes as proxies of genotoxicity. Sampling of mullets was done throughout the year in the important Mondego, Douro and Ave River estuaries (centre and north-western Portugal). The fish (total n = 242) were caught in campaigns made in spring-summer and autumn-winter, using nets or fishing rods. The sampled mullets were comparable between locations in terms of the basic biometric parameters. Blood smears were stained with Diff-Quik to assess the frequencies of six types of ENMAs and MN (given per 1,000 erythrocytes). Some basic water physicochemical parameters were recorded to search for fluctuations matching the ENMAs. Overall, the most frequent nucleus abnormality was the polymorphic type, sequentially followed by the blebbed/lobed/notched, segmented, kidney shaped, vacuolated, MN and binucleated. The total average frequency of the ENMAs ranged from 73 ‰ in the Mondego to 108 ‰ in the Ave. The polymorphic type was typically ≥50 % of the total ENMAs, averaging about 51 ‰, when considering all three estuaries. The most serious lesion-the MN-in fish from Mondego and Douro had a similar frequency (≈0.38 ‰), which was significantly lower than that in the Ave (0.75 ‰). No significant seasonal differences existed as to the MN rates and seasonal differences existed almost only in the Douro, with the higher values in AW. In general, the pattern of ENMAs frequencies was unrelated with the water physicochemical parameters. Considering the data for both the total ENMAs and for each specific abnormality, and bearing in mind that values of MN in fish erythrocytes >0.3 ‰ usually reflect pollution by genotoxicants, it is suggested that mullets were likely being chronically exposed to such compounds, even in the allegedly less polluted ecosystem (Mondego). Moreover, data supported the following pollution exposure gradient: Mondego < Douro < Ave. The scenario and inferences nicely agree with the published data from chemical monitoring. [ABSTRACT FROM AUTHOR]

Present study was performed to examined the metal concentrations in muscle, liver, gonad and gill of gilthead seabream, European seabass, Leaping mullet and Flathead grey mullet from Paradeniz Lagoon, Mediterranean coastal area. The metal concentrations found in muscle tissue varied for Fe: 2.3-51.4, Zn: 6.63-14.8, Cu: 0.38-1.10, Mn: 0.38-1.06, Cr: 0.34-1.13, Ni: 0.58-.074, Pb: 0.32-1.02, Cd: 0.20-0.67 and Co: 0.30-0.61 mg/kg wet weight. Iron showed the highest levels in all tissues, and generally followed by zinc. On the other hand, cadmium, cobalt and lead showed lower levels than other metals. Statistically significant differences were observed in the mean metal values obtained from investigated fish species and their tissues. The levels of metals in the examined fish were well below the regulatory values of various govermental agencies. [ABSTRACT FROM AUTHOR]

The objective of the present work was to determine the optimum dietary protein level for juvenile mullets. Five isocaloric diets were formulated to contain increasing levels (300, 350, 400, 450 and 500 g kg−1) of crude protein (CP) corresponding to 18.7 MJ metabolizable energy kg−1. All diets were tested in triplicate. Each experimental unit was composed of a 50 L tank with 50 juveniles (mean ± SE initial weight and length equal to 1.17 ± 0.02 g and 4.34 ± 0.03 cm respectively). Diets were offered five times a day until apparent satiation for 35 days. No significant difference ( P>0.05) was observed in survival rate, feed efficiency and body composition between treatments. However, weight gain, feed consumption and specific growth rate were higher in fish fed the 350 g kg−1 CP level than those fed the highest protein content diet (500 g kg−1 CP). The amount of postprandial ammonia excreted by mullet was linearly related to protein intake. Intestinal tryptic activity was inversely proportional to the percentage of dietary CP. It is likely that diets containing <350 g kg−1 CP will be needed for on-growing mullet, especially when reared in ponds with abundant natural food. [ABSTRACT FROM AUTHOR]

Abstract: We monitored the contamination by environmental estrogens (EEs) of coastal areas in Korea and Japan using the wild grey mullet. The grey mullet were collected from Ansan, Jeju, Yeosu, Tongyeong, and Busan in Korea and Nagasaki, Omuta, and Fukuoka in Japan. Contamination by EEs was determined by measuring vitellogenin (VTG) levels in serum and identifying gonadal abnormalities histologically (i.e., testis-ova). In four sites in Korea (Ansan, Yeosu, Tongyeong, and Busan) and two sites in Japan (Nagasaki and Fukuoka), serum VTG in immature and male grey mullet was detected at levels greater than 1.0μg/ml, which is considered to be an abnormal level. Although, testis-ova were observed in some individuals collected in Ansan, Tongyeong, and Busan in Korea and Omuta in Japan, there was no correlation between individuals with testis-ova and individuals with abnormal levels of VTG. Furthermore, in Japan, serum VTG levels of fish collected from Nagasaki and Fukuoka were also greater than 1.0μg/ml. Although individuals with testis-ova were found in Omuta, these fish expressed normal levels of serum VTG. Our results suggest that the grey mullets living in these coastal areas are influenced by EEs in the environment. Furthermore, it appears that the production of VTG and the occurrence of testis-ova are caused by different mechanisms. [Copyright &y& Elsevier]

Abstract: Phenanthrene (Phe) is among the most abundant and ubiquitous polycyclic aromatic hydrocarbons (PAHs) in the aquatic environment as a result of human activities. Even so, the knowledge about its impact on fish health is still limited. In this study, the teleost Liza aurata was exposed to 0.1, 0.3, 0.9 and 2.7 µM Phe concentrations during 16 h. Enzymatic antioxidants such as selenium dependent glutathione peroxidase (GPx), glutathione S-transferase (GST), glutathione reductase (GR) and catalase (CAT), as well as a non-enzymatic antioxidant (glutathione — GSH) were quantified in three target organs — gill, kidney and liver. The lipid peroxidation (LPO) was also assessed as a marker of oxidative damage. GPx activity was decreased in gill (0.1 and 0.9 µM), whereas in the liver it was increased (0.3–2.7 µM). GST activity was decreased in kidney (0.3–2.7 µM) and CAT activity was increased in gill after 0.9 µM exposure. GSH content was significantly increased in gill by the lowest concentration and in liver by all Phe concentrations. Despite the antioxidant defense responses, LPO increased in gill (0.3–2.7 µM), kidney (0.1 µM) and liver (0.1 and 2.7 µM). These results revealed organ specific antioxidant defenses depending on the Phe concentration. Liver demonstrated a higher adaptive competence expressed as antioxidant defenses activation, namely GSH and GPX. The lower vulnerability of the kidney to oxidative damage (compared to gill and liver) seems to be related to its higher antioxidant basal levels. Globally, current data highlight the Phe potential to induce oxidative stress and, consequently, to affect the well-being of fish. [Copyright &y& Elsevier]

Total mercury and methylmercury concentrations were measured in the muscle tissue of two fish species from the Ionian and Adriatic seas. Higher total mercury and methylmercury concentrations were detected in striped mullet (Mullus barbatus), a benthic species (Ionian sea: Hg=0.40 μg g-1 wet wt, MeHg=0.40 μg g-1 wet wt; Adriatic sea: Hg=0.49 μg g-1 wet wt, MeHg=0.44 μg g-1 wet wt), than in hake (Merluccius merluccius), a pelagic species (Ionian sea: Hg=0.09 μg g-1 wet wt, MeHg=0.09 μg g-1 wet wt; Adriatic sea: Hg=0.18 μg g-1 wet wt; MeHg=0.16 μg g-1 wet wt). Total mercury residues were determined in all samples of both species from the Adriatic sea, while levels below the limit of detection were registered in 25% and 11%, respectively, of striped mullet and hake samples from the Ionian sea. In 18.8% and 22.2% of striped mullet samples from the Ionian and Adriatic seas, respectively, total mercury concentrations exceeded the maximum level fixed by the European Commission Decision (Hg=0.5 μg g-1 wet wt). In the two different species, mercury was present almost completely in the methylated form with mean percentages between 60% and 100%. The estimated weekly intake for total mercury was below the established the provisional tolerable weekly intake (PTWI) for both species, though their consumption provides a methylmercury intake above the WHO safety limit. [Copyright &y& Elsevier]

Fish communities of five shallow Spanish Mediterranean lakes were studied and stomach content analysed to determine the foraging pattern of each species and the influence on the lake food web. Lakes ranged from 0.5 to 2300 ha with less than 3 m mean depth, while the trophic state varied from mesotrophy to hypertrophy. We fished during summer 2000 and 2001, and for one lake also during spring 2002. Almost no piscivores species were recorded and in general omnivorous species dominated independently of lake trophic state. Fish dietary differences were found among lakes and prey availabilities. Maximum fish biomass and diversity were found in the Albufera lake, where mugilids (Mugil cephalus and Liza aurata) and Cyprinus carpio dominated. The other lakes had young populations of Atherina boyeri and Liza ramada, endemic species (Barbus guiraonis, Aphanius iberus) or introduced species (Lepomis gibbosus, Micropterus salmoides, Gambusia holbrooki). Fish were mainly detritivorous and shifted to zooplanktivorous depending on abundance of large zooplankton. Fish demographic changes and facultative preys influenced food webs of the lakes by both direct predation and indirect nutrient recycling from the sediment. Omnivorous structure of fish communities in these Mediterranean warmer lakes resembles that described in some food webs of tropical lakes. Bottom-up mechanisms seem to be more relevant in warmer lakes and submerged plants were special key factors to maintain clear waters in the study lakes. [ABSTRACT FROM AUTHOR]

The structure and functioning of salt marsh fish communities in the overall ecology of southern African estuaries is poorly understood. This study compares the ichthyofauna associated with a salt marsh creek and eelgrass bed in an attempt to evaluate the relative importance of these habitats to fishes. Taylor's salt marsh creek and adjacent eelgrass bed in the Kariega Estuary were sampled twice per season between the winter of 1992 and the autumn of 1994. The average density and standing stock of fishes were found to be considerably higher in the eelgrass bed than in the intertidal creek. Both habitats had similar fish diversities but were dominated by different taxa, the most notable of which was the dominance of mugilids in the creek and their scarcity in the eelgrass. Taylor's intertidal creek and adjacent eelgrass beds were dominated by juvenile fish, with both habitats functioning as nursery areas for juvenile fish, albeit for totally different ichthyofaunal communities. The similar fish diversities but lower abundances in the intertidal creek compared to the eelgrass beds are in contrast to similar North American studies, and refute the hypothesis that intertidal salt marsh creeks have higher fish densities but lower diversities than eelgrass beds. [ABSTRACT FROM AUTHOR]

Coastal areas in north-western Europe have been influenced by elevated nutrient levels starting in the 1960s. Due to efficient measures, both nitrate and phosphate levels decreased since the mid-1980s. The co-occurring declines in nutrient loadings and fish productivity are often presumed to be causally linked. We investigated whether four resident fish species (twaite shad, bull-rout, thick-lipped grey mullet and eelpout), that spend the majority of their life in the vicinity of the coast, differed in growth between the historic eutrophication period compared to the recent lower nutrient-level period. Based on Von Bertalanffy growth models of length at age, and the analysis of annual otolith increments, we investigated the difference in sex-specific growth patterns and related these to temperature, eutrophication level (Chlorophyll a), growth window and fish density. In all four species, annual otolith growth rates during the early life stages differed between the two periods, mostly resulting in larger lengths at age in the recent period. All species showed significant correlations between increment size and temperature, explaining the observed period differences. The lack of an effect of total fish biomass provided no evidence for density dependent growth. A correlation with chlorophyll was found in bull-rout, but the relationship was negative, thus not supporting the idea of growth enhanced by high nutrient levels. In conclusion, we found no evidence for reduced growth related to de-eutrophication. Our results indicate that temperature rise due to climate change had a greater impact on growth than reduced food availability due to de-eutrophication. We discuss potential consequences of growth changes for length-based indicators used in management. [Display omitted] • Growth study based on an unique otolith collection in terms of species and timespan. • No evidence that de-eutrophication is detrimental for fish growth. • Temperature rise is the main driver of changes in growth. [ABSTRACT FROM AUTHOR]

In this study, a metabolomics approach was applied to investigate the metabolic responses of grey mullet, Mugil cephalus to toxicity induced by heavy metal, Pb (NO3) 2. In addition, the study was followed by assessing the peroxidation index and histology of liver as supplementary data. Pb (NO3) 2 exposure affected the plasma metabolome, especially four group metabolites including amino acids, methylated metabolites, energetic metabolites and citric acid intermediates. Pb (NO3) 2 in medium and high concentrations (15 and 25 μg/l) increased the levels of plasma amino acids compared to control (P < 0.01). In contrast, Pb (NO3) 2 decreased the plasma levels of methylated metabolites (P < 0.01). The ketogenic metabolites and glycerol levels significantly elevated in fish exposed to 25 μg/l Pb (NO3) 2 (P < 0.01). The plasma glucose levels increased in treatment, 5 μg/l Pb (NO3) 2 and after a decline in treatment 15 μg/l Pb (NO3) 2 elevated again in treatment 25 μg/l Pb (NO3) 2 (P < 0.01).The plasma levels of lactate significantly increased in fish exposed to 5 and 15 μg/l Pb (NO3) 2 and then declined to initial levels in treatment, 25 μg/l Pb (NO3) 2 (P < 0.01). The plasma levels of TCA cycle intermediates significantly elevated in treatments 15 and 25 μg/l Pb (NO3) 2 (P < 0.01). As a biomarker of oxidative stress, the plasma levels of malondialdehyde (MDA) showed significant increases in Pb (NO3) 2 exposed fish (P < 0.01). During exposure period, wide ranges of liver tissue damages were also observed in Pb (NO3) 2 exposed fish. In conclusion, exposure to Pb (NO3) 2 affected the metabolome content of blood in grey mullet, mainly through inducing the biochemical pathways related to the metabolism of the amino acids, energetic metabolites and methylated metabolites. Our results may help to understand the effects of heavy metals on fish hematology from a molecular point of view. [Display omitted] • Pb (NO3) 2 exposures affected the plasma metabolome content in grey mullet. • Amino acids, methylated, energetic and citric acid metabolites affected by Pb (NO3) 2 • Pb (NO3) 2 induced lipid peroxidation [ABSTRACT FROM AUTHOR]

Producing food according to the sustainability and "circular economy" principles is considered a strategic goal by several world Institutions. Integrated Multi-Trophic Aquaculture (IMTA) responds to these criteria and stemming from it, the "Self-sufficient Integrated Multitrophic AquaPonic" (SIMTAP) aims to drastically reduce production inputs and waste outputs while maximizing the total food production. In order to succeed, proper selection of the most suitable fish, intermediate organisms and plant species to be grown in the system plays a fundamental role. To validate the SIMTAP concept and experimental prototype, the biological characteristics of fish and other species should be assessed taking into account their complementarity and adaptability to the physical and technical traits of the considered system. This study aimed to identify the most suitable marine organisms for food production within the SIMTAP system and to create a decision model via the DEXi decision support system. Hence, in the present work a brief description of the SIMTAP concept, as well as the biological, zootechnical and commercial characteristics of several candidate fish species, are discussed. The criteria considered to address the species selection were: natural geo-distribution, domestication degree, environmental requirements, feeding regime, growth performances, and market value. The candidate species were: Sparus aurata , Dicentrarchus labrax , Mugil cephalus , Diplodus puntazzo , Seriola dumerili , Umbrina cirrosa , Argyrosomus regius, Psetta maxima, Acipenser spp., Solea spp., Octopus vulgaris. Finally, it seems that the DEXi approach increased the objectivity of the species selection process. Gilthead Sea Bream, European Sea Bass and Flathead Grey Mullet resulted to be the most suitable species for SIMTAP production. • Selecting suitable fish species for marine/brackish water land based IMTA systems • Literature review of the most common aquaculture species in the Mediterranean area • Multi-criteria decision method (DEXi) to select the suitable species • The suitable species selected by DEXi are Sparus aurata and Dicentrarchus labrax • DEXi represents a comprehensive tool for species selection in aquaculture and IMTA [ABSTRACT FROM AUTHOR]

Abstract: The Greek grey-mullet roe is produced from the fully developed gonads of the female mullet (Mugil cephalus) couth in lagoons during their reproductive migration. The traditional processing method of the roe includes, air drying, salting, shape formation and covering with multiple layers of natural beeswax for preservation and distribution. Fish Roe brands have been a staple in local diet and is increasingly becoming popular in the international market. As a ready-to-eat food it’s microbial quality should be of concern for the protection of consumers health. In this study, 48 samples of fish roe, just before waxing, were collected from various local processors for microbiological examination by using selective media and incubated under aerobic and anaerobic conditions. The identification of the bacteria was carried out according to the Bergey’s manual. Microscopic examination of Gram stained cells, catalase, oxidase and biochemical tests were performed when necessary to further identify. V. parahaemolyticus, Vibrio spp., Salmonella spp., and Aeromonas hydrophila were detected in one sample (2%). Shigella spp., and Flavobacterium spp. in two samples (4%), Clotriduim perfringens (vegetative forms), E. coli, and spores of Bacillus spp., were detected in three samples (6%), Staphylococcus aureus in four samples (8%). Various Micrococcus spp., and spores of C. perfringens in 16% and 35% of the samples respectively. From the Listeria genus, only the species Listeria innocua, Listeria welshimeri, Listeria seeligeri Listeria ivanovii and Listeria grayi were recovered from 2 to 10% of the samples. Microbiological analyses revealed the presence of a small number of pathogens in grey-mullet roe samples which are in accordance with the findings of similar studies. Traditional processing of the fish roe, seems inadequate to ensure the food safety and even waxing isn’t expected to fully protect them against facultative anaerobes with salt tolerance. Therefore, additional measures should be taken during processing and marketing of fish roe to minimize potential health risks for the consumers. [Copyright &y& Elsevier]

The activity concentrations of natural radionuclides (210Po and 210Pb) and residual pesticide levels were determined from the fish (red mullet, common sole, anchovy, horse mackerel, gray mullet, and sardine) and mussel samples collected in İzmir Bay seasonally from October 2012 and July 2013. The 210Po and 210Pb concentrations varied between 5.7 ± 4.0 Bq kg−1 dry weight (dw) to 353.7 ± 45.0 Bq kg−1(dw) and 0.7 ± 0.2 Bq kg−1 (dw) to 4.3 ± 0.8 Bq kg−1 (dw), respectively. From a public health point of view, the fish and mussel collected from the İzmir Bay are not harmful to consumers. [ABSTRACT FROM AUTHOR]