Seawater Fish Research Articles

Genotype by environment interactions of harvest growth traits for barramundi (Lates calcarifer) commercially farmed in marine vs. freshwater conditions

Barramundi (Lates calcarifer), also known as Asian seabass, is a commercially important tropical aquaculture species farmed in diverse culture production systems and salinities (marine to freshwater). Despite adaptability to different culture conditions, selective breeding programs to improve growth rates in barramundi should consider the impact of genotype by environment (GxE) interactions on genetic gains. Barramundi juveniles from 144 families, originating from 24 dams and 54 sires were farmed in a seawater (SW) raceway in Bowen (QLD, Australia) and a freshwater (FW) pond environment in Townsville (QLD, Australia) - both operated under commercial culture conditions. Fish were sampled at 15 months post-hatch (mph) in the SW raceway (mean 1718 ± 309 g weight (W), 454 ± 28 mm total length (Lt) and 141 ± 11 mm body depth (BD) (n = 752)) and at 21 mph in the FW pond (mean 1905 ± 426 g W and 451 ± 39 mm Lt and 144 ± 15 mm BD (n = 752)). DNA parentage analyses were used to assign progeny to their respective parents, and the final dataset comprised of 1116 offspring. Moderate-low heritability estimates were found for body traits (W h2 = 0.46 ± 0.10; Lth2 = 0.41 ± 0.12; BD h2 = 0.49 ± 0.13; body shape H h2 = 0.41 ± 0.12; and Fulton's K condition factor h2 = 0.15 ± 0.07). Deformities (Def) were observed in 1.8% of fish in SW and 25.1% of fish in FW, although negligible additive genetic effects were evident (Def h2 = 0.05 ± 0.04). GxE interactions were found to be moderate for harvest growth traits (W GxE rg = 0.81 ± 0.11; Lt GxE rg = 0.64 ± 0.18; BD GxE rg = 0.78 ± 0.13; H GxE rg = 0.71 ± 0.17), and high for Fulton's K condition factor (K GxE rg = 0.36 ± 0.31; P > 0.05). This study reveals the presence of weak to moderate re-ranking of genotypes for harvest growth traits in L. calcarifer farmed in marine and freshwater conditions, suggesting that GxE interactions should be taken into account in a breeding program servicing multiple environments. Incorporation of sib-information from extreme salinity environments into the selection criteria of a breeding program may therefore optimize the realization of genetic gains across distinct commercial conditions.

Shifts in Herring and Mackerel Resources in the North Sea under Global Warming

Zeng, Y., 2020. Shifts in herring and mackerel resources in the North Sea under global warming. In: Yang, D.F. and Wang, H. (eds.), Recent Advances in Marine Geology and Environmental Oceanography. Journal of Coastal Research, Special Issue No. 108, pp. 151–155. Coconut Creek (Florida), ISSN 0749-0208.The shift of habitats for economic marine species may pose a great challenge to the existing fishing industry. Under the current business model, fish populations may migrate too far to be caught by small fishing companies. Herring and mackerel are two extremely important species in the North Sea fisheries. This research takes herring and mackerel as examples to establish mathematical models to find out why and how small fishing companies near the North Sea should prepare for the potential challenges due to global warming. The annual change of seawater temperature in the next 50 years is predicted based on CMIP6. Combining seawater temperature prediction and fish life patterns, the migration prospects of fish populations are obtained. Results are carefully charted on the map using MATLAB, making the findings vivid and precise. The extent to which fish may move north is different in selected scenarios, which is analyzed and discussed. This study provides valuable insights into how climate change may affect the North Sea's ecosystem and fishing industry.

An osmolality/salinity-responsive enhancer 1 (OSRE1) in intron 1 promotes salinity induction of tilapia glutamine synthetase

Euryhaline tilapia (Oreochromis mossambicus) are fish that tolerate a wide salinity range from fresh water to > 3× seawater. Even though the physiological effector mechanisms of osmoregulation that maintain plasma homeostasis in fresh water and seawater fish are well known, the corresponding molecular mechanisms that control switching between hyper- (fresh water) and hypo-osmoregulation (seawater) remain mostly elusive. In this study we show that hyperosmotic induction of glutamine synthetase represents a prominent part of this switch. Proteomics analysis of the O. mossambicus OmB cell line revealed that glutamine synthetase is transcriptionally regulated by hyperosmolality. Therefore, the 5′ regulatory sequence of O. mossambicus glutamine synthetase was investigated. Using an enhancer trapping assay, we discovered a novel osmosensitive mechanism by which intron 1 positively mediates glutamine synthetase transcription. Intron 1 includes a single, functional copy of an osmoresponsive element, osmolality/salinity-responsive enhancer 1 (OSRE1). Unlike for conventional enhancers, the hyperosmotic induction of glutamine synthetase by intron 1 is position dependent. But irrespective of intron 1 position, OSRE1 deletion from intron 1 abolishes hyperosmotic enhancer activity. These findings indicate that proper intron 1 positioning and the presence of an OSRE1 in intron 1 are required for precise enhancement of hyperosmotic glutamine synthetase expression.

Comparison of the distribution and diversity of antimicrobial resistance genes between wild and commercially available Atlantic Mackerel

The global uncontrolled rise of antimicrobial resistance (AMR) is a major societal threat and it is well documented that AMR is already negatively affecting healthcare and intensive livestock farming systems. Nonetheless, capture fisheries are still essential to the global food supply providing over 50% of the world’s aquatic organism production. To facilitate improved management, it is therefore imperative that we better understand reservoirs of AMR and how gene transmission occurs in the aquatic environment. In order to discern which AMR bacteria and genes are present in the marine environment, sediment and seawater samples were collected and Atlantic Mackerel were captured at the beginning of summer and autumn in the Solent Strait (Portsmouth, U.K). In addition, commercially available Atlantic mackerel were purchased at a local fish market. Using culture-dependent techniques we obtained more than 700 bacterial and 20 fungal isolates from skin, intestinal lining, and intestinal content. Ten different cefotaxime-resistant Pseudomonas spp. were isolated from the seawater and market fish skin samples, and one cefotaxime-resistant Rhanella sp. was isolated from wild fish digesta. Results from ongoing whole-genome shotgun metagenomics analysis will be discussed, as well as the connection between AMR bacteria and AMR gene presence within the marine coastal environment and the local fish markets, which are the last link between capture fisheries and consumers.

PROTEOLITIC BACTERIA CULTURE OF ISOLATION RESULTS IN ORGAN LIVING OF FISHING GROUPER CULTURE RESULTS

The grouper is a sea water fish that is often cultivated. But in digesting feeds is often not optimal. To improve feed efficiency, one effort that can be done is to know the activity of proteolytic bacteria in milkfish digestion. The purpose of this study was to determine the presence and activity of proteolytic bacteria. The method used is the observation method with a purposive sampling technique. The abundance of bacteria in the digestive tract is calculated by the TPC (Total Plate Count) method. Based on the research results, it is known that there are proteolytic bacteria in the digestion group which are indicated by the presence of a clear zone around the bacterial colony that is grown on specific media (skim milk). There is also the activity of proteolytic bacteria in the digestion grouper by measuring the hydrolyzed clear zone with an average in the anterior part of the intestine 2.3 mm, middle 2.6 mm, posterior 2.65 mm. The results of this study indicate that the bacteria bacillus sp with sorbitol media, molasses and nutrient broth with a storage time of 40 days at 4 0C did not experience a decrease in bacterial density that was significantly different.

Lipid profile and health benefit of commonly consumed fresh water and sea water fish species in the population of Serbia

Background/Aim. Dietary intake of n-3 long-chain polyunsaturated fatty acids (LC-PUFA) is important in prevention and treatment of different diseases. In general population, the average intake of n-3 LC-PUFA is often significantly lower than recommended levels. Fish lipids are rich sources of these fatty acids, of which the most important are eicosapentaenoic (20:5 n-3, EPA) and docosahexaenoic (22:6 n-3, DHA) fatty acids. This study was designed to determine and compare fat, fatty acids and lipid quality indices in 10 commercial fish species available on the Serbian market, as well as relation between their price and nutritional value. Methods. Freshwater fish originated from the Danube River in the Belgrade Region, while seawater fish were mostly from the Adriatic Sea. A gas chromatography method was used to define fatty acids in 40 fish samples after lipid extraction. Cost-minimization analysis was conducted to assess the economic utility. Results. Seawater fish had a significantly higher value of flash lipid quality compared to the freshwater fish (p < 0.05). Value of hypercholesterolaemic fatty acids (OFA) for the freshwater group was 18.70 (17.40?21.30) while the seawater group had a similar range of values 18.90 (17.55?22.75). Hypocholesterolaemic fatty acids (DFA) also showed similar ranges for both groups: 68.80 (66?70.20) for freshwater and 68.40 (64.85?73.05) for seawater group. The ratio of DHA/EPA ranged from 1.8 for sardine samples and up to 10 for tuna samples, indicating that the amount of DHA in natural samples exceeds the amount of EPA in many cases. The values of atherogenic (AI) and thrombogenic index (TI) were lower than 1 for all analysed samples. Conclusion. Sardine and mackerel had the highest content of n-3 LC-PUFA and presented the least expensive sources of EPA and DHA. The low values of AI and TI obtained from studied fish indicate its benefits from a health point of view.

Choline and phosphatidylcholine, but not methionine, cysteine, taurine and taurocholate, eliminate excessive gut mucosal lipid accumulation in Atlantic salmon (Salmo salar L)

Excessive enterocyte lipid accumulation, with the suggested term lipid malabsorption syndrome (LMS), is frequently observed in Atlantic salmon (Salmo salar L), in small fish in fresh water as well as in large fish in seawater. The symptoms indicate insufficient supply of components involved in lipid assimilation. The questions addressed in the present work were whether dietary supply of components involved in phospholipid and sterol metabolism might prevent LMS. Atlantic salmon (35 fish, 330 g per 600 L tank) were fed a low fish meal diet (LF) as such or supplemented with taurocholate at two levels (3.5 and 6.9 g/kg), cholesterol (2.0 g/kg), taurine (0.8 g/kg), phosphatidylcholine (15.1 g/kg), choline (3.7 g/kg), cysteine (0.8 g/kg) or methionine (1.0 g/kg). A high fish meal diet (HF) was also included. The overall growth rate of the fish was high (TGC>4.2) with no significant effects of diet. Fish fed the LF diet showed increased relative weight of the pyloric and mid intestine and excessive lipid accumulation in the enterocytes, characteristics which were nearly absent in fish fed the HF diet and the LF diet supplemented with choline and phosphatidylcholine. The phosphatidylcholine supplemented diet showed significantly higher lipid digestibility than the LF diet. None of the other supplements eliminated the signs of excessive enterocyte lipid accumulation. Phosphatidylcholine down-regulated pcyt1a, involved in the phosphatidylcholine synthesis, and both choline and phosphatidylcholine induced apoaIV, important in lipoprotein assembly, and markedly suppressed the lipid droplet marker plin2. Methionine supplementation did not stimulate endogenous synthesis of choline. Cholesterol supplementation suppressed sterol uptake and de novo cholesterol synthesis, and induced sterol efflux from the intestinal mucosa. Taurocholate and taurine induced their respective metabolic pathways. All feed supplements, in particular cholesterol and cysteine, down-regulated genes related to antiviral, chemokine, antigen presentation, immunoglobulinfunctions, as well as of extracellular proteases. The results of this study confirm the results from our previous study showing that choline or phosphatidylcholine is a necessary ingredient in low fish meal diets.

Monitoring pharmaceuticals and personal care products in water and fish from the Gulf of Urabá, Colombia

Gulf of Urabá is considered a tourist zone of Antioquia Department attracts a large number of visitors to explore the aquatic ecosystem and beaches thus offering a large economic benefit. However, this region has been affected by various anthropogenic effects thus generating an environmental problematic that affect aquatic ecosystem. Over the years, several research has been evaluated pollutant such as pesticides, metals and physicochemical parameters, even our laboratory had found several toxic metals in fish from this same area.The presence of emerging pollutant in matrices such as seawater and fish from Gulf of Urabá have not been reported, and to the best of our knowledge, this is the first study. This work presents important aspects relating to sampling, monitoring and surveillance of seawater and several fish species caught in the area in order to determinate the content of emerging pollutant (triclosan, ibuprofen, diclofenac) using UPLC-QqQ/MS. In general, all three pharmaceuticals in different sampling sites were detected and total concentrations ranged from 0.10 to 1.54 μg/L in surface water. However, emerging pollutants content in fish muscle was not detected. In addition, a high variability in triclosan, ibuprofen and diclofenac concentrations according to the season of sampling was found. Regarding to seasonal variations, most emerging pollutant in the surface water had variation in levels both dry and wet season. Better removal was presented in the dry season, due to stronger irradiation and greater activity of microorganisms.

Calycomorphotria hydatis gen. nov., sp. nov., a novel species in the family Planctomycetaceae with conspicuous subcellular structures

A novel strain belonging to the family Planctomycetaceae, designated V22T, was isolated from sediment of a seawater fish tank in Braunschweig, Germany. The isolate forms pink colonies on solid medium and displays common characteristics of planctomycetal strains, such as division by budding, formation of rosettes, a condensed nucleoid and presence of crateriform structures and fimbriae. Unusual invaginations of the cytoplasmic membrane and filamentous putative cytoskeletal elements were observed in thin sections analysed by transmission electron microscopy. Strain V22T is an aerobic heterotroph showing optimal growth at 30 °C and pH 8.5. During laboratory cultivations, strain V22T reached generation times of 10 h (maximal growth rate of 0.069 h−1). Its genome has a size of 5.2 Mb and a G + C content of 54.9%. Phylogenetically, the strain represents a novel genus and species in the family Planctomycetaceae, order Planctomycetales, class Planctomycetia. We propose the name Calycomorphotria hydatis gen. nov., sp. nov. for the novel taxon, represented by the type strain V22T (DSM 29767T = LMG 29080T).

Modification of Chicken Egg Shell and Lime Extract (Citrus amblycarpa) for Minimizing Lead (Pb) Level on Blood Cockles (Anadara granosa).

Heavy metal in human body generally is from food consumed by the human either through fish or other aquatic animals in fresh water or seawater which are polluted by heavy metal. The presence of heavy metal in human body in certain level can cause several diseases, such as kidney disease, liver, nerve, and brain disease. Moreover, this research aimed at analyzing the decrease of lead (Pb) level on blood cockles (A. granosa) through engineering of stirring time, adsorption temperature, and variation of lime extract (C. amblycarpa) concentration by using Stirring Chamber tools through using chicken egg shell adsorbent. The research design used simple experiment in posttest only control group design. Meanwhile, the subject in this research was divided by two groups randomly in which a treatment was given to one group as control group and experiment group. Sample of blood cockles that was used was in 72 samples. Lime extract concentration in 1%, 1.5%, and 2% in stirring time of 5 minutes, 10 minutes, and 15 minutes before and after heating in 35°C utilized stirring speed in 150 rpm. Meanwhile, the chicken egg shell adsorbent was in 50 gram for each treatment. The sampling technique in this research utilized purposive sampling and data was analyzed by utilizing Statistic test of Two-Way Anova. Result showed that Pb level in fresh blood cockles before heating was 0.223 ppm and after heating, it reduced to be 0.062 ppm. Result of hypothesis test was obtained p-value <0.05, which was 0.000, and it indicated that there was a significant enhancement of chicken egg shell adsorption capacity in minimizing Pb level on blood cockles after being conducted the addition of lime extract with temperature variation and stirring time in certain stirring speed through engineering tool of Stirring Chamber. All in all, conclusion of this research was there was a significant enhancement of modified chicken egg shell adsorption capacity and lime extract in minimizing Pb level on blood cockles. Moreover, it was expected that this research could give contribution to food technology in reducing heavy metal of Pb level in pre-treatment of blood cockles (Anadara granosa) with modifying lime extract and chicken egg shell through Stirring chamber tool.

Molecular cloning of insulin-like growth factor 3 (igf3) and its expression in the tissues of a female damselfish, Chrysiptera cyanea, in relation to seasonal and food-manipulated reproduction

Food availability is a permissive determinant that drives gonadal activity in fish. The present study aimed to clarify the interactions between reproductive and nutritive statuses in the sapphire devil (Chrysiptera cyanea), a tropical damselfish with a long-day preference for reproduction. Insulin-like growth factor 3 (IGF3), a novel IGF that likely plays a role in gonadal maturation, was closely monitored in the sapphire devil. The cDNA of sapphire devil igf3 had an open reading frame of 443 base pairs (146 amino acid residues). Phylogenetic analyses revealed that sapphire devil IGF3 was clustered within the teleost IGF3 family. The transcript levels of sapphire devil igf3 increased in the brain, liver, and ovary of the fish during the late vitellogenic phase, suggesting that it plays a role in reproduction. Immersion of the fish in seawater containing estradiol-17β suppressed transcript levels of sapphire devil igf3 in the liver, but not in the brain, suggesting that intensive protein synthesis in relation to vitellogenesis negatively impacts somatic metabolism in this tissue. When fish were reared with high or low food under conditions of photoperiod (LD = 14:10) and temperature (at 25–28 °C) during the non-reproductive season, ovarian development was induced in high-food fish. Furthermore, prior to ovarian development in the high-food fish, the transcript levels of sapphire devil igf3 increased in the brain, liver, and ovary. These results indicated crosstalk between the reproductive and growth networks and suggested that a metabolic shift, from growth mode to reproductive mode, occurs in peripheral tissues when nutritive status is improved under suitable conditions of photoperiod and water temperature.

The acute toxic effects of hexavalent chromium on the liver of marine medaka (Oryzias melastigma)

Chromium is toxic to marine animals and can cause damage to many of their organs, including the liver. To test the toxicity of chromium on marine organisms, we exposed the liver of the marine medaka (Oryzias melastigma) with hexavalent chromium [Cr(VI)]. Our results show that Cr enrichment in the liver demonstrates a positive correlation to the exposure concentration. With the increase of Cr(VI) concentration, pathological changes including nuclear migration, cell vacuolization, blurred intercellular gap, nuclear condensation, become noticeable. To further study changes in gene expression in the liver after Cr(VI) exposure, we used RNA-seq to compare expression profiles before and after Cr(VI) exposure. After acute Cr(VI) exposure (2.61 mg/l) for 96 h, 5862 transcripts significantly changed. It is the first time that the PPAR pathway was found to respond sensitively to Cr(VI) exposure in fish. Finally, combined with other published study, we found that there may be some difference between Cr(VI) toxicity in seawater fish and freshwater fish, due to degree of oxidative stress, distribution patterns and detailed Cr(VI) toxicological mechanisms. Not only does our study explore the mechanisms of Cr(VI) toxicity on the livers of marine medaka, it also points out different Cr(VI) toxicity levels and potential mechanisms between seawater fish and freshwater fish.

Salinity-dependent pharmacokinetics of florfenicol in Nile tilapia (Oreochromis niloticus) and its implication in optimal dosing regimen

Nile tilapia has been cultured in a wide salinity range, from freshwater to up to 15 ppt brackish water due to its euryhaline characteristics. As salinity profoundly affects the physiology of freshwater and seawater fish in a different way, it is conceivable that pharmacokinetic (PK) behavior should also exhibit salinity-dependency. The current study aimed to investigate the effect of salinity on PK of florfenicol (FF) in Nile tilapia reared at 0, 2, 4, 8, and 15 ppt after a single intravenous (IV) or oral (PO) administration of 15 mg/kg at 28 °C. The implication of salinity-dependent PK in the optimal dosing regimen determination was also examined. The serum concentrations of FF were analyzed by HPLC-UV method and PK parameters were determined by the 2-compartmental model. Following IV injection, increasing water salinity from 2 to 15 ppt lead to a shorter elimination half-life (t1/2β) from 11.22 to 9.03 h, faster drug clearance (CL) from 0.047 to 0.056 L/kg/h, and smaller area under the serum concentration-time curve (AUC) from 326.19 to 267.74 h·μg/mL, suggesting a more rapid elimination at a higher salinity level. The results from PO study were generally consistent with the IV experiment except for the unchanged AUC over a salinity range of 0 to 15 ppt likely due to greater bioavailability at higher salinity. However, the absorption rate of FF was not significantly influenced by salinity as there were no significant differences in t1/2Ka, Cmax, and Tmax among the 5 salinity levels. The optimal dosing regimens were determined by the pharmacokinetic-pharmacodynamic approach for each salinity level and it was revealed that the calculated dosages were similar between 0 and 8 ppt salinity, but a higher dosage was required at 15 ppt (from 7 to 10 mg/kg/day at the MIC of 2 μg/mL). Therefore, Nile tilapia reared at saltwater required a higher FF dosage than those cultured at freshwater.

UTILIZATION OF SAMBUNG NYAWA LEAF EXTRACTS Gynura procumbens (Lour) Merr. FOR TREATMENT OF Vibrio alginolyticus IN TIGER GROUPER (Epinephelus fuscoguttatus Forsskal, 1775)

Tiger Grouper is one of the sea water fish commodities that is quite popular with the community and has a high economic value. The problem faced by farmers is the attack of Vibriosis, one of which is caused by the Vibrio alginolyticus bacteria. The use of synthetic antibiotics has been widely used but has many adverse effects, so it needs new alternatives for the treatment of Vibriosis disease. One of them is by using the extract of lifelong leaf extract. Life-sustaining plants (Gynura procumbens) contain secondary metabolites such as flavonoids, tannins, and antibacterial saponins. This study aims to determine the best dosage of lifelong leaf extract for the treatment of Vibriosis disease in tiger grouper. The study was conducted in two stages, namely in vitro and in vivo. Before the fish were treated with feed that had been given a sambung deca leaf extract, the fish were challenged using Vibrio alginolyticus with a density of 108 CFU / mL as much as 0.1 mL / head and then fed with treatment and maintained for 21 days. The results of the in vitro study showed that the life of sambung leaf extract at a dose of 700 ppm had a broad inhibitory effect on V. alginolyticus, which amounted to 10.47 mm compared to other treatments. Whereas when continued for in vivo testing, a dose of 350 ppm in general has been applied for the treatment of attacks of Vibrio alginolyticus in tiger grouper.

Anatomical and Histological Study of Shark (Carcharhinus sorrah) Kidney

Sharks are sea water fishes belong to the class Chondrichthyes, Subclass Elasmobranchii. Sharks are cartilaginous fish that have a different osmoregulation process than any other sea water fish. Cartilaginous fish is the only vertebrate that can maintain urea. This study aims to determine the anatomical and histological structure of the kidney in the anterior, medial and posterior parts of kidney. The study was conducted by observing anatomy of the kidney. Histological preparations were made using the paraffin method. Qualitative descriptive data analysis was done. Research results show that shark kidneys consist of three parts, namely the head kidney, the body kidney, and the tail kidney. Kidney sharks are brownish red with a size of 18 cm long. Histological observations of shark kidney in the head kidney reveals many glomerulus, body kidney reveals many distal and tubule proximal contractile tubules whereas tail kidney reveals stroma that is rarely found in vertebrate kidney.

Animal utilization based on local knowledge in Ciletuh Geopark, Ciemas Subdistrict, Sukabumi, West Java, Indonesia

Abstract. Wulandari I, Shanida SS, Husodo T, Megantara EN, Tresna D. 2019. Animal utilization based on local knowledge in Ciletuh Geopark, Ciemas Subdistrict, Sukabumi, West Java, Indonesia. Biodiversitas 20: 2781-2789. Ciletuh Geopark has high biodiversity but has not been supported by local knowledge about the use of animals to support sustainable development. This study aims to investigate: (i) the number of species that are used, (ii) distribution of local knowledge about animals using, and (iii) the dependency of communities on creatures in Ciletuh Geopark, Ciemas Subdistrict, Sukabumi. Mixed methods of qualitative (semi-structured interviews) and quantitative methods (proportional random sampling) were applied in this study. The community uses 153 species, consisting 58 Avifauna species, 13 mammals species, nine Herpetofauna species, three insects species, 16 species of freshwater fish, 43 species of seawater fish, two Mollusca species, and nine crustacean species. Utilization of fauna is not distributed in each village. Animals using of Avifauna, Herpetofauna, insects, and mammals tend to be utilized by people of Girimukti Village. Seawater fish, Mollusca, and crustaceans tend to be utilized by Ciwaru Village, while freshwater fish tend to be used in each village, except Girimukti and Cibenda Village. Utilization of fauna in Ciemas Subdistrict has begun to be abandoned, although several people still use them.

First polychlorinated biphenyls (PCBs) monitoring in seawater, surface sediments and marine fish communities of the Persian Gulf: Distribution, levels, congener profile and health risk assessment

Polychlorinated biphenyls (PCBs) are persistent organic pollutants that, due to their high toxicity, lipophilic property and widespread dispersal in the global environment, present a danger for human health and ecological systems. Although the inventory and use of PCBs are extensively reported worldwide, the status of PCBs in Iran is still unknown. In this study, the concentrations of PCBs were determined in the environmental matrices and in five commercially important fish species from Larak coral Island, Persian Gulf, Iran, in winter and summer 2015. A positive correlation was found among PCBs levels and congeners profiles in seawater (0.97–3.10 ng L−1), surface sediments (2.95–7.95 ng g−1dw) and fish samples (7.20–90.19 ng g−1dw), indicating fish as suitable bioindicator of environmental PCBs contamination. In all matrices, a high contribution of light and medium chlorinated congeners was detected in both seasons. In fish, the higher PCBs levels were found for both sexes in both seasons in liver and kidney than other tissues (skin, gonad, muscle) due to their high lipid content and PCBs lipophilicity. More importantly, the risks for human health associated with fish consumption were also evaluated, and it was found that all the toxicity indices measured for PCBs were within the World Health Organization (WHO) permissible limit of food consumption. However, it is highly recommended to inform the local population about potential risks attributable to dietary incorporation of locally caught fish, and establish a surveillance monitoring programme on PCBs in this region.

Current state and trends in the content of 137Cs and 90Sr in abiotic and biotic components of Arctic ecosystems (Barents and Kara Seas case study)

This publication summarizes long-term data on radioactive contaminants in seawater, bottom sediments, and marine fish and describes current patterns in radionuclide distribution using data collected by the Murmansk Marine Biological Institute during cruises to the Barents and Kara Seas in 2015–2017. During the study period, no short-lived artificial radionuclides were found in the Barents and Kara Seas. 137Cs and 90Sr isotopes with a longer half-life are still registered in Atlantic waters that are the main source of radioactive contamination in these Arctic seas. Volumetric activity of 137Cs and 90Sr was compared at different depths. A uniform distribution of 137Cs in the vertical column of water and a tendency to increase the volume activity of 90Sr from surface to bottom were observed in the Barents Sea. Bottom sediments in the Kara Sea contain on average 2 times more 137Cs than the Barents Sea. Atlantic cod is characterized by an extremely low concentration of 137Cs in muscular tissue, about an order of magnitude lower than in the period of maximum contamination of Barents Sea waters observed in 1982. Currently there is a decreasing trend in concentrations of anthropogenic radioisotopes in the environment and biota. Processes of 137Cs and 90Sr removing from biotic and abiotic components are described with exponential functions. Due to natural marine purification processes, the decrease of 137Cs and 90Sr concentrations in the Barents and Kara Seas occur 2–4 times faster than the physical radioactive decay of these radionuclides.

Interactive effects of strontium and barium water concentration on otolith incorporation in juvenile flounder Paralichthys olivaceus.

Although the relationship between the incorporation of an element into otoliths and the concentration of the element in water has been extensively investigated in many fish species, the interactive effects of multiple elements in water on the otolith incorporation of an element are not adequately explored or well understood. In this study, 16 treatments in triplicate using strontium (Sr; 1, 2, 3 and 4 times the ambient baseline, 6.5 mg l-1) and barium (Ba; 1, 2, 4 and 6 times the ambient baseline, 40 μg l-1) as categorical variables in an orthogonal design were established to evaluate the relative or interactive effects of water elements on otolith elemental incorporation in juvenile flounder Paralichthys olivaceus (from 15 to 116 days post hatching). The results revealed that otolith incorporation (Me:CaOtolith) of Sr and Ba were positively dependent on the concentrations of the elements in water (Me:CaWater). Overall, Sr was incorporated into otoliths more efficiently than was Ba, and the partition efficiency (DMe) of both elements decreased with increasing water elemental concentrations. Increasing Sr concentrations in water appeared to negatively affect the uptake of Ba into otoliths rather than facilitate it, as previously reported in fish reared in freshwater and brackish water, or showed no effect on fish in seawater. Conversely, the Ba concentration in water did not influence the otolith uptake of Sr, which agrees with the findings for other fish species. When applying otolith microchemistry to fish ecology studies, it is essential to cautiously address the interactive effects of multiple elements in the environment on otolith elemental incorporation.

Parasites Inventory in Freshwater and Seawater fish at Fish Quarantine Center and Quality Control of Fisheries Product in Surabaya II

One disease that often attacts fish is a group of parasites or parasitic diseases, parasites are not only dangerous because they are related to their activities, but also trigger the emergence of other pathogenic organisms and cause infections. Therefore, it is necessary to take fish quarantine measures to prevent the spread of diseases carried out by fish quarantine centers. This study was conducted to determine the type of parasite that infested fish samples and determine the prevalence and intensity of fish samples. A total of 48 sample fish consisting of freshwater and seawater fish were analyzed in the laboratory of Balai Karantina Ikan, Pengendalian Mutu dan Keamanan Hasil Perikanan Surabaya II during December - January 2019, either directly or directly (ectoparasites and endoparasites). Parasitic identification was carried out visually and microscopically with an approach based on identification books. The types of parasites that we found during the study consisted of Argulus sp, Trichodina sp, Anisakis sp., Gnathostoma spinigerum, and Gnathostoma spinigerum. The highest prevalence in Scomber Scombrus with Anisakis sp. Amounting to 77.8%, mean while, the lowest prevalence and the intensity is found in Thunnus sp. The prevalence and intensity of parasites are influenced by water quality and pollution.