Metabolic costs associated with seawater acclimation in a euryhaline teleost, the fourspine stickleback (Apeltes quadracus).

The cost of osmoregulation in teleosts has been debated for decades, with estimates ranging from one to 30 % of routine metabolic rate. The variation in the energy budget appears to be greater for euryhaline fish due to their ability to withstand dynamic salinity levels. In this study, a time course of metabolic and physiological responses of the euryhaline fourspine stickleback (Apeltes quadracus) acclimated to freshwater (FW) and then exposed to seawater (SW) was examined. There was 18% mortality in the first 3 days following exposure to SW, with no mortalities in the FW control group. Gill Na+/K+-ATPase (NKA) activity, an index of osmoregulatory capacity, increased 2.6-fold in SW fish peaking on days 7 and 14. Gill citrate synthase activity, an index of aerobic capacity, was 50-62% greater in SW than FW fish and peaked on day 7. Tissue water content was significantly lower in the SW fish on day 1 only, returning to FW levels by day 3. Routine metabolic rate was decreased within 24 h of SW exposure and was maintained slightly (8-22%) but significantly lower in SW compared to FW water controls throughout the 2-week experiment. These results indicate that elevated salinity resulted in increased SW osmoregulatory and aerobic capacity in the gill, but with a reduced whole animal metabolic rate to this euryhaline species.

Assessment of seasonal relationship between polycyclic aromatic hydrocarbon accumulation and expression patterns of oxidative stress-related genes in muscle tissues of red mullet (M. barbatus) from the Northern Adriatic Sea.

In this study, we examined the seasonal association between Polycyclic Aromatic Hydrocarbon (PAH) concentrations and mRNA expression profiles of some antioxidant genes (i.e. CAT, GST and SOD), as well as lipid peroxidation (LPO), in muscle of sexually inactive females of red mullet (Mullus barbatus). Fish were captured in a fishery area of the Northern Adriatic Sea during both winter and summer. We found significantly (p < 0.05) higher ∑HMW-PAHs concentrations in muscle of specimens caught during winter than summer. On the basis of sampling season, red mullets exhibited different gene expression profiles of antioxidant enzymes showing lower levels of both CAT and GST in winter than in summer. Accordingly, CAT was found to be negatively associated with ∑PAH concentrations, especially ∑LMW-PAH, in individuals collected during winter. Seasonal-related downregulation of some oxidative stress biomarker expression is suggestive of greater susceptibility of red mullets to PAHs during winter.

Water quality of the Meuse watershed: Assessment using a multi-biomarker approach with caged three-spined stickleback (Gasterosteus aculeatus L.).

The use of a multi-biomarker approach with three-spined sticklebacks (Gasterosteus aculeatus) through an active biomonitoring strategy appears to be a promising tool in water quality assessment. The present work proposes to assess the efficiency of these tools in the discrimination of some sites in a large scale on the Meuse basin in Europe. The study was part of an EU program which aims to assess water quality in the Meuse across the French-Belgian border. Sticklebacks were caged 21 days upstream and downstream from the wastewater treatment plants (WWTPs) of Namur (Belgium), Charleville-Mézières (France), Bouillon (Belgium) and Avesnes-sur-Helpe (France). First, the state of a variety of physiological functions was assessed using a battery of biomarkers that represented innate immunity (leucocyte mortality and distribution, phagocytosis activity, respiratory burst), antioxidant system (GPx, CAT, SOD and total GSH content), oxidative damages to the membrane lipids (TBARS), biotransformation enzymes (EROD, GST), synaptic transmission (AChE) and reproduction system (spiggin and vitellogenin concentration). The impacts of the effluents were first analysed for each biomarker using a mixed model ANOVA followed by post-hoc analyses. Secondly, the global river contamination was assessed using a principal component analysis (PCA) followed by a hierarchical agglomerative clustering (HAC). The results highlighted a small number of effects of WWTP effluents on the physiological parameters in caged sticklebacks. Despite a significant effect of the "localisation" factor (upstream/downstream) in the mixed ANOVA for several biomarkers, post-hoc analyses revealed few differences between upstream and downstream of the WWTPs. Only a significant decrease of innate immune responses was observed downstream from the WWTPs of Avesnes-sur-Helpe and Namur. Other biomarker responses were not impacted by WWTP effluents. However, the multivariate analyses (PCA and HAC) of the biomarker responses helped to clearly discriminate the different study sites from the reference but also amongst themselves. Thus, a reduction of general condition (condition index and HSI) was observed in all groups of caged sticklebacks, associated with a weaker AChE activity in comparison with the reference population. A strong oxidative stress was highlighted in fish caged in the Meuse river at Charleville-Mézières whereas sticklebacks caged in the Meuse river at Namur exhibited weaker innate immune responses than others. Conversely, sticklebacks caged in the Helpe-Majeure river at Avesnes-sur-Helpe exhibited higher immune responses. Furthermore, weak defence capacities were recorded in fish caged in the Semois river at Bouillon. This experiment was the first to propose an active biomonitoring approach using three-spined stickleback to assess such varied environments. Low mortality and encouraging results in site discrimination support the use of this tool to assess the quality of a large number of water bodies.

Survey on Heavy Metals Contamination and Health Risk Assessment in Commercially Valuable Asian Swamp Eel, Monopterus albus from Kelantan, Malaysia.

This work investigates the metals concentration in the tissues of Asian swamp eel, Monopterus albus. Five selected tissues, including liver, gill, bone, skin, and muscle were examined for the concentration of Zn, Cu, Cd, Pb, and Ni. The concentrations of Cd and Pb were found high in the muscle tissues of the eels. Additionally, high amounts of Zn and Cu metals were observed in the liver, whereas the Cd, Pb, and Ni metals were highly detected in gill. The accumulation of Zn, Cu, Cd, Pb, and Ni in both skin and bone of the eel seems to vary between seasons. Low levels of Zn, Cu, and Ni were identified in the muscle tissues of the eels. This study revealed that the concentration of Cd and Pb in the muscle tissues of Asian swamp eels exceeded the permissible limits by the US EPA, suggesting the consumption of the muscle may be hazardous and can severely affect one's health.

Heavy metals and minerals contents in pikeperch (Sander lucioperca), carp (Cyprinus carpio) and flathead grey mullet (Mugil cephalus) from Sidi Salem Reservoir (Tunisia): health risk assessment related to fish consumption.

The aim of this study was to investigate heavy metals and selected minerals contents in filets of pikeperch (Sander lucioperca), carp (Cyprinus carpio) and flathead grey mullet (Mugil cephalus), the major fish species produced in Sidi-Salem reservoir; the largest Tunisian freshwater ecosystem. Concentrations of Ca, Mg, Fe, Zn, Cd, Pb and Hg were determined by inductively coupled plasma-optical emission spectrometry, while concentrations of Na and P were determined by flame photometry and spectrophotometry, respectively. Results concerning heavy metals are considered quantitatively reliable for Hg and Cd but must be taken with precautions concerning Pb levels as the LOD (limit of detection) of the analytical process was higher than acceptable limit. They showed greater accumulations of both Hg and Cd in filets of pikeperch than in filets of carp and mullet, but none of the values exceeded the normative maximum levels (0.500 and 0.050 mg kg-1 w.w., respectively). Considering provisional intakes, target hazard quotient and hazard index, estimated for a fish portion per week, consumption of any of the species did not appear to be potentially hazardous for the health as they were far below threshold values. A fish portion would provide substantial amounts (>15% of daily requirements) in essential mineral nutrients (P, Mg and Fe) and thus should be considered an interesting contribution to a healthy diet. It is strongly advocated to authorities including freshwater fish in the official national annual control survey of contaminants in fishery products, which in addition to guaranteeing security of consumers, would also allow diversifying valorisation opportunities and thus increase the economic value of this fish production.

Total mercury in muscles and liver of Mugil spp. from three coastal lagoons of NW Mexico: concentrations and risk assessment.

Total mercury (Hg) concentrations were determined by atomic absorption spectrophotometry in muscles and liver of composite samples of Mugil cephalus and M. curema collected during November 2013 and in January, April, and July 2014 from the coastal lagoons Altata-Ensenada del Pabellón (AEP), Ceuta (CEU), and Teacapán-Agua Brava (TAG) of Sinaloa State. The mean Hg contents and information on local consumption were used to assess the possible risk caused by fish ingestion. Mean total mercury levels in the muscles ranged from 0.11 to 0.39 µg/g, while the range for liver was 0.12-3.91 µg/g. The mean Hg content of the liver was significantly (p < 0.001) higher than that of the muscles only in samples collected from AEP. Although total Hg levels in the muscles were lower than the official permissible limit, the HQ values for methyl mercury calculated for the younger age classes of one fishing community were >1, indicating a possible risk for some fishing communities of the Mexican Pacific coast.

Assessment of trace element contamination and bioaccumulation in algae (Ulva lactuca), mussels (Perna perna), shrimp (Penaeus kerathurus), and fish (Mugil cephalus, Saratherondon melanotheron) along the Senegalese coast.

Concentrations of 11 elements were quantified in five marine species from different trophic levels of a food web (algae, mussel, shrimp and fish), representative for shallow Senegalese coastal waters, and including species of commercial importance. Significant differences in element concentrations and bioaccumulation were demonstrated, revealing the utility of employing a suite of organisms as bioindicators to monitor metal contamination in coastal areas. There was no clear seasonal pattern in concentration of elements, however inter-site differences were observed. Calculations of transfer factors for all the studied elements showed that transfer factors from water were greater than those from sediments. For shrimp and mussel, the concentrations of Pb and Cd were below the EU's maximum level for human consumption, however high concentrations of arsenic in shrimp were recorded at all sites.

Assessment of biological effects of environmental pollution in Mersin Bay (Turkey, northeastern Mediterranean Sea) using Mullus barbatus and Liza ramada as target organisms.

The increasing emphasis on the assessment and monitoring of marine ecosystems has revealed the need to use appropriate biological indicators for these areas. Enzyme activities and histopathology are increasingly being used as indicators of environmental stress since they provide a definite biological end-point of pollutant exposure. As part of an ecotoxicological assessment of Mersin Bay, EROD enzyme activity and histopathological response in selected organs and tissues of two species of fish, Mullus barbatus (red mullet) and Liza ramada (thinlip grey mullet), captured from area were examined. Pollutant (Organochlorines (OC), alkylphenols (APs) and BPA) levels and biomarker responses in tissue samples were evaluated together for their potential to alter the metabolism and cellular aspects in liver and gonad. Elevated induction of EROD activity and histopathological alterations in contaminated samples from Mersin Bay was observed compared to reference site indicating the exposure to potential pollutants.

Preliminary assessment of contaminants in the sediment and organisms of the Swartkops Estuary, South Africa.

Urban estuaries are susceptible to metal and organic pollution, yet most remain understudied in South Africa with respect to the presence, concentrations and distribution of contaminants. Metal and organic chemical concentrations were assessed in sediment and organisms from different trophic levels in the lower reaches of the Swartkops Estuary. Species sampled included Upogebia africana (Malacostraca: Upogebiidae), Gilchristella aestuaria (Clupeidae), Psammogobius knysnaensis (Gobiidae), Mugil cephalus (Mugilidae), Lichia amia (Carangidae), Argyrosomus japonicus (Sciaenidae), Pomadasys commersonnii (Haemulidae) and Larus dominicanus (Avis: Laridae). This study is one of the most comprehensive studies to date assessing pollution levels in a food web in estuaries in South Africa. Due to biomagnification, higher concentrations of Arsenic, Lead, Mercury and Cadmium were found in the juveniles stages of popular angling fishes. High concentrations of Cadmium and Arsenic were recorded in the liver of L. amia, A. japonicus and P. commersonnii which exceed international quality food guidelines. Eggs from the gull, L. dominicanus, showed detectable concentrations of PCBs.

Aboriginal Consumption of Estuarine Food Resources and Potential Implications for Health through Trace Metal Exposure; A Study in Gumbaynggirr Country, Australia.

Fishing and resource use continues to be an essential aspect of life for many Aboriginal communities throughout Australia. It is important for dietary sustenance, and also retains deep social, cultural and economic significance, playing a fundamental role in maintaining group cohesion, transferring cultural knowledge and affirming Indigenous identities. We surveyed approximately 20% of the Gumbaynggirr Aboriginal community of Nambucca Heads, New South Wales, Australia. This paper explores Gumbaynggirr Connection to Country and engagement in cultural practice. It quantifies fishing efforts and consumption of seafood within the community. We found 95% of the sample group fish, with the highest rate of fishing being 2-3 times a week (27%). Furthermore, 98% of participants eat seafood weekly or more frequently, up to more than once a day (24%). Survey results revealed that Myxus elongatus (Sand mullet) and naturally recruited Saccostrea glomerata (Sydney rock oysters) continue to be important wild resources to the Gumbaynggirr community. Trace metals were measured in M. elongatus and S. glomerata samples collected by community participants in this study. Maximum levels prescribed in the Australia New Zealand Food Standards Code were not exceeded in the edible tissue for either species, however both species exceeded the generally expected levels for zinc and copper and S. glomerata samples exceeded the generally expected level for selenium. Furthermore the average dietary exposure to trace metals from consuming seafood was calculated for the surveyed population. Trace metal intake was then compared to the provisional tolerable weekly intake prescribed by the Joint Expert Committee on Food Additives. This process revealed that copper and selenium intake were both within the provisional tolerable weekly intake, while there is no guideline for zinc. Furthermore, participants relying heavily on wild resources from the Nambucca River estuary may exceed the provisional tolerable weekly intake for cadmium. This suggests the need for further investigation of this issue to minimize any possible health risk.

The assessment of trace metals at gill, muscle and liver tissue in Mugil cephalus.

In this paper, concentrations of trace metals such as Cr, Mn, Fe, Ni, Cu, As, Se, Ag, Cd and Pb were determined in Mugil cephalus of the middle Black Sea coasts by employing inductively coupled plasma mass spectrometry (ICP-MS) and microwave digestion technique. Different parts of fish samples were analysed separately such as the gill, muscle and liver. The accuracy of the results has been checked by using a certified reference material (DORM-4). The highest trace metal values determined in different parts of fish were Cr in muscle tissue (0.416 µg/g), Mn in gill tissue (52.246 µg/g), Fe in muscle tissue (11.899 µg/g), Ni in muscle tissue (108.057 µg/g), Cu in liver tissue (261.911 µg/g), As in liver tissue (4.162 µg/g), Se in liver tissue (11.418 µg/g), Ag in liver tissue (0.323 µg/g), Cd in liver tissue (1.11 µg/g) and Pb in gill tissue (3.047 µg/g). These results were also compared with various relevant literature and guidelines.

Bioaccumulation and ecological risk assessment of heavy metals in the sediments and mullet Liza klunzingeri in the northern part of the Persian Gulf.

The concentrations of some heavy metals (Cu, Zn, Pb and Cd) were investigated in the sediments and in the mullet Liza klunzingeri from the northern part of the Persian Gulf. The levels of Cu, Zn and Pb in the sediment varied significantly among the sampling sites (P<0.05). Sediments from the northern part of the Persian Gulf had serious ecological risk when considering PER. The ranges of the average concentrations of Cu, Zn, Pb, and Cd in the tissue of L. klunzingeri were 10.00-16.66 mg/kg, 18.75-32.50 mg/kg, 3.25-14.16 mg/kg and 0.37-3.33 mg/kg, respectively. The health risk analysis of individual heavy metals in the fish tissue indicated dangerous levels of Pb and Cd for the general population at some sampling sites.

An assessment of heavy metal bioaccumulation in Asian swamp eel, Monopterus albus, during plowing stages of a paddy cycle.

Livers and muscles of swamp eels (Monopterus albus) were analyzed for bioaccumulation of heavy metals during the plowing stage of a paddy cycle. Results showed heavy metals were bioaccumulated more highly in liver than muscle. Zinc (Zn) was the highest bioaccumulated metal in liver (98.5 ± 8.95 µg/g) and in muscle (48.8 ± 7.17 µg/g). The lowest bioaccumulated metals were cadmium (Cd) in liver (3.44 ± 2.42 µg/g) and copper (Cu) in muscle (0.65 ± 0.20 µg/g). In sediments, Zn was present at the highest mean concentration (52.7 ± 2.85 µg/g), while Cd had the lowest mean concentration (1.04 ± 0.24 µg/g). The biota-sediment accumulation factor (BSAF) for Cu, Zn, Cd and nickel (Ni) in liver tissue was greater than the corresponding BSAF for muscle tissue. For the three plowing stages, metal concentrations were significantly correlated between liver and muscle tissues in all cases, and between sediment and either liver or muscle in most cases. Mean measured metal concentrations in muscle tissue were below the maximum permissible limits established by Malaysian and U.S. governmental agencies, and were therefore regarded as safe for human consumption.

Assessment of reproductive biomarkers in three-spined stickleback (Gasterosteus aculeatus) from sewage effluent recipients.

The aim of this study was to examine the occurrence of endocrine disruption close to sewage treatment plant effluent discharges along the Finnish Baltic Sea coast using a set of reproductive biomarkers present in adult three-spined stickleback (Gasterosteus aculeatus). Possible variation and sensitivity of the biomarkers during an entire reproductive period were also examined. The analysis of vitellogenin (VTG) for estrogenic activity and spiggin for androgenic activity, together with histopathological analysis indicated that sticklebacks were exposed to estrogenic loads sufficient to cause inappropriate production of VTG and to disrupt normal testicular structure in adult male sticklebacks. No androgenic disruption was observed. The results emphasize the need of a combination of several reproductive biomarkers in fish and repeated sampling for the detection of potential endocrine modulating substances under field condition.

Assessment of microcystins in lake water and fish (Mugilidae, Liza sp.) in the largest Spanish coastal lake.

Cyanobacteria dominance and cyanotoxin production can become major threats to humans and aquatic life, especially in warm shallow lakes, which are often dominated by cyanobacteria. This study investigates the occurrence and distribution of microcystins (MCYST) in water, cell-bound and in the tissues of the commercial mugilid Liza sp. in the largest, coastal, Spanish Mediterranean lake (Albufera of Valencia). This is the first report concerning microcystin accumulation in tissues of mugilid fish species. Considerable amounts of microcystins were found in the water and seston, which correlated with development of Microcystis aeruginosa populations in the lake. The MCYST concentrations found in Lake Albufera (mean 1.7 and 17 µg/L and maximum 16 and 120 µg/L in water and seston, respectively) exceeded by one to two orders of magnitude the guideline levels proposed by the World Health Organization and were higher than that reported in other lakes of the Mediterranean zone. The presence of MCYST was found in all the fishes studied and accumulated differently among tissues of the commercial species Liza sp. Toxin accumulation in fish tissues showed that although the target organ for MCYST was the liver, high concentrations of microcystins were also found in other analysed tissues (liver>intestine>gills>muscle). Human tolerable daily intake for microcystins is assessed relative to the WHO guidelines, and potential toxicological risks for humans, wildlife and related ecosystems of the lake are discussed.

Costly major histocompatibility complex signals produced only by reproductively active males, but not females, must be validated by a 'maleness signal' in three-spined sticklebacks.

Olfactory information about individual major histocompatibility complex (MHC) immune genotypes is important for mate choice in several species. For example, during the mate choice decisions of three-spined sticklebacks, females assess males on the basis of odour cues that convey information about their MHC diversity. Here, we show that an additional 'maleness' signal is needed to validate the MHC signal. Furthermore, using interaction between natural odour of sticklebacks and synthetic MHC-ligand peptides, we show that MHC signals are conditional on the reproductive state in males. By contrast, we find that gravid females do not produce such signals. Since MHC olfactory signals relevant to mate choice decisions are conditional upon gender and reproductive state, we suggest that their manufacture is likely to be costly to senders, and therefore, potentially conditional on the health/parasitization status of the sender. We hypothesize that shedding of peptide-MHC complexes compromises immune function, selecting against unconditional use of these signals.

Performance assessment for determining malachite green and leucomalachite green in swamp eel (Monopterus albus) muscle using assigned reference values in a proficiency test.

This paper presents the results of a proficiency test (APLAC T058) for malachite green (MG) and leucomalachite green (LMG) in swamp eel (Monopterus albus). The programme was organized by the Hong Kong Government Laboratory and Hong Kong Accreditation Service (HKAS), under the auspices of the Asia-Pacific Laboratory Accreditation Co-operation (APLAC) in 2007. Results submitted by participants were compared with the assigned reference values, which were determined by an accurate liquid chromatography-isotope dilution mass spectrometry (LC-IDMS) technique, and their performance was evaluated on the basis of z-score index. The distribution of data was very wide and discrepancy from the assigned reference values was found to be method dependent. Only 48% and 62% of participants achieved satisfactory z-scores (i.e. |z|

Contamination assessment of a coastal lagoon (Ria de Aveiro, Portugal) using defence and damage biochemical indicators in gill of Liza aurata--an integrated biomarker approach.

Fish gill importance in toxicants uptake, bioconcentration and excretion allied to meagre knowledge on branchial damage/protection responses substantiate this study. Five critical sites in Ria de Aveiro (Portugal) were assessed in comparison with a reference site (Torreira), focusing on Liza aurata gill antioxidant defences versus damage (oxidative and genetic). Only in Barra fish displayed damage (lipid peroxidation) though no differences were found in antioxidants. In all other sites, except Rio, antioxidant alterations were found. Thus, fish from Gafanha, Laranjo and Vagos showed higher total glutathione, glutathione peroxidase and catalase. Higher glutathione reductase and glutathione S-transferase activity was also found in the first and the last sites, respectively. In Laranjo, metallothionein levels were higher though lower in Gafanha and Vagos. In general, damage was not accompanied by defences weakening confirming that predicting damage based on antioxidants depletion is not straightforward. The integrated biomarker response index ranked sites as: Gafanha>Barra>Laranjo>Vagos>Rio>Torreira.

Assessment of seasonal variability of biomarkers in three-spined stickleback (Gasterosteus aculeatus L.) from a low contaminated stream: implication for environmental biomonitoring.

In this study, wild three-spined sticklebacks were sampled every six weeks, between April and October, in a low contaminated stream. For all fish, physiological indexes, such as condition factor, hepato-, gonado- and nephro-somatic index were calculated to determine fish condition and reproductive status. Moreover, a set of biomarkers including biotransformation enzymes, oxidative stress parameters, neurotoxicity and endocrine disruption markers was measured. The results allowed to determine biomarker variability due to fish gender or sampling season. For example, 7-ethoxyresorufin-O-deethylase activity, glutathione peroxidase as well as vitellogenin and spiggin exhibited strong gender differences. Conversely, lipoperoxidation and acethylcholinesterase activity were characterised by a lack of gender and seasonal variation, and can be considered as more robust parameters for a field application. The present work allowed to establish practical guideline for biomarker measurements in wild sticklebacks and to define a reference system which can be used to analyze variations in future monitoring studies.

Detection and assessment of androgenic potency of endocrine-disrupting chemicals using three-spined stickleback, Gasterosteus aculeatus.

The male three-spined stickleback (Gasterosteus aculeatus) produces a glue protein named "spiggin" that is used as a cementing substance for building its nest. The synthesis of spiggin is under the control of androgenic stimulation. Therefore, spiggin is an effective biomarker of any androgenic activity displayed by environmental chemicals, similarly to the use of vitellogenin as an estrogenic biomarker. The aim of this study was to establish a quantification system for spiggin mRNA to develop a highly sensitive system for evaluating environmental androgens. In this process, two different types of cDNA encoding spiggin (SPG-1 and SPG-2) were isolated. They closely resemble each other in primary structure and features. In addition, the transcriptions of both spiggin gene were induced by only androgenic stimulation in a receptor-mediated manner. These findings suggest the multiplicity albeit specificity of spiggin in the stickleback. The quantification system for spiggin mRNA was established using a real-time RT-PCR technique. This system enables accurate quantification within a wide range of spiggin mRNA from 10(1) to 10(6) copies.