Sampled Fish Species Research Articles

Growth Patterns, Status of Well-Being and Trend Analysis of Three Commercially Important Clupeid Species from Selangor Landing Port

Length-weight relationships (LWRs) and condition factors are vital to quickly understanding the fitness and well-being of fish. There is currently no available evidence on LWRs, condition factors and landing trend for these three species and an absence of this information will result in improper management and monitoring of fish species. In this study, the growth patterns, status of well-being and trend analysis of commercially important clupeid species from the west coast of Peninsular Malaysia were studied. Sardinella lemuru, Amblygaster sirm and Nematalosa japonica were selected due to high commercial value and conservation status. S. lemuru was specifically categorized as near threatened by the IUCN with decreasing global populations. Total length (cm) and body weight (g) of S. lemuru, A. sirm and N. japonica were accounted for in this study, which was obtained from the wet market in the west coast of Peninsular Malaysia. The relationships between length and, weight and, condition factors (Fulton’s, KF; relative condition factor, Kn; Allometric) were assessed. The allometric equation; W = aLb was used to evaluate the length-weight relationships while KF = 100W/Lb and Kn = W/aLb were used to estimate fish condition factor. ARIMA (1,1,1) and ARIMA (0,1,0) models were utilised to forecast the fish landing pattern until 2030. The results showed that the coefficient of determination R2 values varied between 0.263 (Sardinella lemuru), 0.5187 (Amblygaster sirm) and 0.8443 (Nematalosa japonica) and b values ranged from 0.0959 to 2.1005. From this, all three fish species have shown a negative allometric growth pattern b<3, reflecting a relatively slow growth rate and size of fish. No positive allometry was detected for any of the sampled fish species. A low value of relative condition factor (Kn < 1) suggests that all the fish species in this study have poor physical characteristics due to inadequate food resources, and unsuitable habitats for expansion of the fish population. Prediction based on Autoregressive Integrated Moving Average (ARIMA) model showed that N. japonica would increase gradually in the coming years, while S. lemuru would remain constant. This study contributes to the knowledge base for S. lemuru, A. sirm and N. japonica in the west coast of Peninsular Malaysia, and is crucial in terms of understanding the ecology of the habitat for supporting conservation strategies, and the restoration and management of these species in future.

A case study on blast fishing in illegal small scale fisheries in the Aegean Sea: Catch composition and observed external and internal abnormalities for 18 Osteichthyes fish species

Blast fishing is an illegal, ecologically destructive fishing method, fatal for many fish species at large scales. Blast fishing using dynamite is preferred by the fishers, especially small scale fisheries in Turkey, as it requires minimal effort but still results in higher catches. In the current study, demonstration of 20 controlled real-time blasting results involves species composition, size of fish, catch rates, catch composition, commercial/discard ratios, CPUE estimates and clinical observations of external and internal abnormality symptoms of fish species. Blasting trials were carried out with special permission in limited numbers because of its harmful effect. The collected data was tested using PRIMER v6 and diversity indices were also analysed. For the similarity between collected species cluster analysis was used to examine the stability of the results. Multidimensional scaling (MDS) was also applied for the assessment of fish species in the catch. A total of 1014 individuals (63.8 kg) were collected and 18 fish species belonging to seven families were examined. According to laboratory examinations, it was found that blasting caused different external and internal abnormality symptoms in the sampled fish species during the study.

Growth Performance and Muscle Composition of Carps (Labeo rohita, Catla catla, Cirrhinus cirrhosus and Hypophthalmichthys molitrix) at Different Protein Diets under Polyculture Farming

This study investigated the effects of three supplemental diets varying in protein percentage (T1- 28%, T2- 30%, and T3- 32%) on the fillet composition of Rohu (Labeo rohita), Catla (Catla catla), Mrigal (Cirrhinus cirrhosus), and Silver Carp (Hypophthalmichthys molitrix) reared in ponds with supplemental diets. The control treatment with no supplemental feeding was also included to conduct the experiment. Fish from control ponds had substantially lower mean muscle protein concentrations than fish from ponds that received supplemental feeding, with 28% and 30% protein diets producing the most muscle protein. Compared to other treatments, fish fed a diet containing 32% protein had significantly (p<0.05) higher muscle lipid concentrations (2.22%). The muscle carbohydrates were greater in fish from ponds fed 28% protein diets. The Rohu (L. rohita) had the highest percent of muscle protein among the three sampled fish species, while Silver carp (H. molitrix) had the lowest, with all other species having intermediate values. The Mrigal (C. cirrhosus) and Silver Carp (H. molitrix) had the highest carbohydrate in their muscles, while Rohu (L. rohita) had the least carbohydrate content. During polyculture of cyprinids in ponds, the supplemental feeding of diets with protein ranging from 28 to 30% protein can be recommended as an optimal protein diet to attain the higher growth performance of carps avoiding the wastage of feed at the farmer’s level in semi-intensive polyculture farming.

The trophic ecology of an invasive predator in a novel ecosystem: Green sunfish Lepomis cyanellus in a restored urban stream

Rapid urbanization will increase the number of novel stream ecosystems in the Southeastern United States. The green sunfish (Lepomis cyanellus) is a globally widespread, invasive species that is particularly well-adapted to urban stream conditions. The trophic ecology of green sunfish is understudied, especially in the novel ecosystems where they appear to thrive. We assessed predation by green sunfish in the food web of a heavily engineered and restored urban stream in Raleigh, North Carolina. We sampled fish species composition, size structure, abundance, the benthic macroinvertebrate assemblage, and fish diets during two seasons. Green sunfish was the sole species inhabiting the study stream, with the exception of a single goldfish. The population size structure indicated potential overcrowding in our study ecosystem. Chironomidae was the most common taxa in both the benthic macroinvertebrate assemblage and in fish diets during the summer. We observed a seasonal shift in diets to lesser prey-specific abundance of Chironomidae and a greater overall abundance of terrestrial prey from summer to winter. Green sunfish can persist in small restored urban streams of the Southeast US where virtually no other fish occur, and they utilize benthic invertebrates and terrestrial prey as resources.

Internal injuries in marine fishes caught in beam trawls using electrical versus mechanical stimulations

Abstract To improve the ecological and economic sustainability in the Dutch beam trawl fishery, tickler chains were replaced by electrical pulse stimulation to drive common sole (Solea solea) out of the seabed. Because electrical stimulation may cause internal injuries, we quantified this risk by sampling fish species from commercial beam trawlers and recording spinal injuries and haemorrhages from X-radiographs and autopsy. To distinguish mechanically-induced and electrical-pulse-induced injuries, we compared injuries in ten species sampled from pulse (PUL) and tickler-chain (TCK) trawlers and four species sampled from PUL trawlers with the stimulus switched on or off. Co-occurrence of a major spinal injury and major haemorrhage at the same location was only observed in PUL samples, and were frequently (40%) observed in Atlantic cod (Gadus morhua) and in low numbers (0–2%) in whiting (Merlangius merlangus), grey gurnard (Eutrigla gurnardus), and greater sandeel (Hyperoplus lanceolatus), but not in flatfishes and other species. In cod, injury occurrence correlated with fish length, with lower probabilities for small fish. Major spinal injury or major haemorrhage occurrence in PUL (range: <1–16%) was lower than in TCK (range: <1–42%) in eight of the ten species studied. Population level consequences of pulse-induced injuries are considered negligible.

Comparing novel shotgun DNA sequencing and state-of-the-art proteomics approaches for authentication of fish species in mixed samples

Replacement of high-value fish species with cheaper varieties or mislabelling of food unfit for human consumption is a global problem violating both consumers’ rights and safety. For distinguishing fish species in pure samples, DNA approaches are available; however, authentication and quantification of fish species in mixtures remains a challenge. In the present study, a novel high-throughput shotgun DNA sequencing approach applying masked reference libraries was developed and used for authentication and abundance calculations of fish species in mixed samples. Results demonstrate that the analytical protocol presented here can discriminate and predict relative abundances of different fish species in mixed samples with high accuracy. In addition to DNA analyses, shotgun proteomics tools based on direct spectra comparisons were employed on the same mixture. Similar to the DNA approach, the identification of individual fish species and the estimation of their respective relative abundances in a mixed sample also were feasible. Furthermore, the data obtained indicated that DNA sequencing using masked libraries predicted species-composition of the fish mixture with higher specificity, while at a taxonomic family level, relative abundances of the different species in the fish mixture were predicted with slightly higher accuracy using proteomics tools. Taken together, the results demonstrate that both DNA and protein-based approaches presented here can be used to efficiently tackle current challenges in feed and food authentication analyses.

Linking fish and crustacean taxonomic composition with seasonal contrasts in the soft-bottom intertidal zone.

The primary objective of this study was to investigate the seasonal fish and crustacean variations concerning taxonomic composition, species richness, and diversity in sandy beach habitat. For this purpose, we investigated the Sonmiani Hor lagoon area during four distinct seasons, i.e., northeast (NE) monsoon, pre-monsoon, south-west (SW) monsoon, and post-monsoon for one year. During each haul, the net was pulled about 100m along the beach in 0.5m depth. The results showed a strong linear correlation between the diversity index and equitability in fishes (r = 0.978). The diversity index was strong negatively correlated with the abundance and biomass (r = -0.978, -0.972, respectively). The physical attributes like sea surface water temperature and salinity showed a strong negative effect on species assemblages (r = -0.981 and -0.943, respectively). The mean air and water temperature illustrated approximately 3°C difference during NE and pre-monsoon seasons. However, salinity, pH, and electrical conductivity did not show any significant seasonal variabilities. Under the ecological indices, the fish species displayed higher diversity (H' = 3.19) during SW monsoon, whereas the lowest diversity was observed during pre-monsoon (H' = 1.58). The equitability and species richness, however, remained more noticeable during SW monsoon (J' = 0.81). The total number of individuals of fish and crustaceans reached 4799 with 3813 fish individuals and 986 individuals of crustaceans. A total of 27 families of fish while five crustacean families comprising of 30 genera and 38 fish species while ten genera and 17 species of crustaceans were recorded. Liza subviridis displayed the highest abundance among the sampled fish species. In conclusion, fish species constituted a significant part of the coastal fauna in the study area. The seasonal variations displayed distinct variations in fish species composition and diversity.

FOOD RESOURCE SHARING AMONG BENTHIC AND NEKTONIC STREAM FISH SPECIES

Several tropical freshwater fish species are generally generalistic feeders, sometimes followed by a diet reduction during the period of decreased resource availability. This study aimed to analyze the dietary overlap between nektonic and benthic fish species. The stomachs of 82 obligatory nektonics and 52 benthic were removed. The diet composition for each individual was determined based on the analysis of the stomach content, and the contents were grouped into 11 categories. For the analysis of food items, the method of degree of food preference was used. To verify the niche overlap between benthic and nectonic, the Pianka index was applied. Benthic species consumed items across all 11 food categories and nektonic species consumed nine. The diet composition of species with nektonic and benthic habits showed a significant difference. Dietary overlapping suggests a supply of the same resources, as they are shared by both groups. The high concentration of water insect larvae in the food content of all sampled fish species, regardless of the position in the water column, shows the importance of insects in the water ecosystems. The composition of ecosystem diets is helpful towards understanding the community structure and can explain the coexistence between different fish’s groups where live in different micro-habitats and how tactics used to capture food which may minimize the effects of overlapping and competitive exclusion.

Universal performance of benzalkonium chloride for the preservation of environmental DNA in seawater samples

AbstractEnvironmental DNA (eDNA) analysis allows noninvasive and cost‐effective monitoring of macroorganisms' distribution and composition in aquatic ecosystems. Benzalkonium chloride (BAC) is an inexpensive and simple preservative for eDNA in water samples and has been used in many eDNA studies for preventing its degradation during transportation. However, its preservation performance has limitedly been evaluated by species‐specific assays, targeting short fragments of mitochondrial DNA in freshwater and brackish ecosystems. Here, we examined the performance of BAC in preserving eDNA in seawater samples, targeting different fragment lengths of mitochondrial and nuclear eDNA, and community information inferred by eDNA metabarcoding. We quantified the time series changes of Japanese jack mackerel (Trachurus japonicus) eDNA concentrations in experimental tanks and inshore seawater to compare the yields and decay rates of eDNA between BAC treatments. For both tank and field samples, BAC treatment substantially suppressed the degradation of all types of target eDNA and increased the eDNA yields at the start of the experiment. In addition, we performed eDNA metabarcoding targeting fish community to compare the species richness and composition in seawater samples between BAC treatments, showing that the number of fish species in field samples hardly varied throughout a day by BAC treatment. Our findings indicate high versatility of BAC in preserving both the quantitative (copy number) and the qualitative (species richness) information on various types of aqueous eDNA in various environmental conditions. BAC should therefore be used to minimize the false‐negative detection of eDNA, regardless of target genetic regions, fragment sizes, environmental conditions, and detection strategies.

Seasonal comparision of levels of cadmium chloride in fresh water fish Catla catla of Bilawali and Sirpur Lake

Fresh water bodies are facing serious type of pollution of heavy metal. Heavy metals are a metal of relatively high density, relative atomic weight or atomic number. Heavy metal are either essential nutrients (like cobalt, zinc) and other may be toxic (like cadmium, mercury, lead). Heavy metals cannot be easily removed by processes like oxidation, precipitation or other processes because they are stable compounds. For aquatic organisms and humans, Cadmium is a toxic non-essential heavy metal that is introduced to environment as a result of the weathering of soil/ rocks, from volcanic eruption /from various human activities involving mining and processing of ore, use of fertilizers and pesticides. Cadmium can affect biological functions in fish and cause severe histopathological, biological and physiological changes in various fish species. The three body parts of fish had been taken gills, muscle and liver because the heavy metal enter in body by three possible ways gills, skin and digestive tract in fish and then transported by blood to either a storage point such as bone, or to liver for transportation. The mean highest values of concentrations of heavy metal in dry tissues of all sampled fish species collected from Sirpur Lake and Bilawali Lake is pointed out in results. These levels might be due to anthropogenic inputs and industrial activity around the lake. The change in season may also contribute to differences in uptake of heavy metal. The purpose of this study is to check the tissue-specific heavy metal accumulation in the fresh water fish (Catla catla) in two different seasons.

Comparative Assessment of the Nutritional Fitness of Wild and Cultured African Catfish (Clarias gariepinus)

The nutritional qualities of wild and cultured Clarias gariepinus from Oba Reservoir, Ikose, Ogbomoso, Oyo State, Nigeria, and the cultured fish from the Department of Fisheries and Aquaculture, Oyo State Ministry of Agriculture and Mineral Resources, Ogbomoso, Oyo State, Nigeria, were evaluated. The proximate composition, mineral element composition and essential amino acids profile of the sampled fish species were evaluated using standard laboratory procedures. The results of the proximate composition was observed to be high in cultured population compared to the Wild and there was a statistical significant difference in the amount of crude protein, fibres, carbohydrate, fat/lipid, ash and moisture contents across the two sampled populations (Wild; 17.94 ± 0.19, Cultured; 21.06 ± 0.51), t = -5.738, p-value =0.001. Mineral element content showed maximum amount of copper (Cu), Lead (Pb), Manganese (Mn) and Iron (Fe) in Wild population than in their cultured counterpart while the amount of Cadmium (Cd) and Nickel (Ni) observed in Wild population were undetected. It was also discovered that all amino acid analysed were found to be higher in the cultured group compared to the wild. There were varied levels of significant correlations among all the measured amino acids contents across the two sampled populations. This study showed that the proximate composition, elemental contents and amino acids profiles of both the cultured and wild fishes varies significantly and the results proofed that the cultured fish sample were more nutritious than the wild population, therefore, good monitoring system of Oba Reservoir should be encouraged with strict vigilance.

Better boundaries: identifying the upper extent of fish distributions in forested streams using eDNA and electrofishing

AbstractThe management of species that occur in low densities is a conservation concern worldwide across taxa with consequences for managers and policymakers. The distribution boundary at the upper extent of fish in North America receives extra attention because stream reaches with fish are managed differently and often have more protections than fishless reaches. Here, we examine the relative reliability of water environmental DNA (eDNA), polymerase chain reaction (PCR)‐amplified for Coastal Cutthroat Trout (Oncorhynchus clarkii clarkii) to detect the upper extent of fish across streams as a potential management tool compared to standard electrofishing methods. We provide estimates of fish detection probabilities from eDNA analyses, and probabilities of detection for both eDNA field samples and quantitative PCR (qPCR) given covariates of habitat characteristics and fish densities from electrofishing. We present a primer and probe based on the cytochrome oxidase I gene using qPCR to detect trout DNA across water samples from 60 forested streams in the Pacific Northwest, USA using high‐resolution spatial sampling. In 28% of streams, the upper extent of fish matches between methods. In over half of the streams, Coastal Cutthroat Trout eDNA was detected above the electrofishing last‐fish boundary. Although some detections could be attributed to false‐positive errors, eDNA results extend the upstream, leading edge of fish by 50–250 m from the electrofishing boundary. In 20% of the streams, detections of last‐fish occurred higher in the stream network with electrofishing rather than eDNA, but generally by only 50 m. Modeled results revealed that the occurrence of trout eDNA was higher in wider‐stream locations and that eDNA detections occurred at lower electrofishing densities (<5 trout per 50 linear m). We also showed that three replicate eDNA samples were sufficient to capture trout eDNA when eDNA was present. Although eDNA constitutes an effective addition to approaches to delimit the upper extent of fish, its effectiveness depends on previous knowledge of the last‐fish boundary to apprise where to start sampling and targeting fish species anticipated to be last‐fish. We present evidence that eDNA is a valuable tool in investigating fish distributions taking its place alongside traditional high‐effort catch–release tools.

Composition, structure and diversity of fish assemblages across seascape types at Príncipe, an understudied tropical island in the Gulf of Guinea (eastern Atlantic Ocean)

Coastal seascapes are often composed of a mosaic of interconnected habitats. Transitions between adjacent habitats are of special relevance to the ecology of many reef-associated organisms. In this study, we tested (i) whether the degree of similarity in the composition and structure of coastal fish assemblages differed between three interconnected seascape types, and (ii) whether differences in taxonomic and phylogenetic diversity of the fish assemblages were consistent between the seascape types. We sampled fish species from diverse habitats in the shallow coastal waters surrounding the island of Príncipe (Gulf of Guinea, eastern Atlantic Ocean), an understudied and remote tropical island. Specifically, video transects were carried out by SCUBA divers at three seascape types: rocky reefs, rocky reef–rhodolith bed transitions, and rocky reef–sandy bottom transitions, to extract presence/absence and ordinal abundance data, across a range of depths (9–31 m), covering the entire perimeter of the island. A total of 71 fish taxa were recorded. Both the composition and structure of the fish assemblages differed between the studied seascapes. The mean number of fish species (taxonomic diversity) was higher on ‘reefs’ than in both the ‘reef–rhodolith bed’ and ‘reef–sandy bottom’ transitions. In contrast, the taxonomic distinctness index (phylogenetic diversity) was higher for fish assemblages in both transitional seascape types than on rocky reefs. Hence, at the island-scale, the protection of local fish assemblages needs to consider a representative network of interconnected habitats, including at these seascapes boundaries where important ecological functions seem to occur.

Prevalence of nematode parasite, Contracaecum, in Nile tilapia, African catfish and Barbus species in Lake Hawassa, Ethiopia

A cross-sectional study was conducted from November 2017 to March 2018 at Lake Hawassa to determine the prevalence of larval Contracaecum infestation in Nile tilapia, (Oreochromis niloticus), African Catfish (Clarias gariepinus) and Barbus species (Barbus intermedius). Fifty-two point six per cent (52.6%) previous prevalence and 5% precision were used to estimate the sample size. Accordingly, a total of 383 randomly sampled fish species comprising of 163 (42.6%) C. gariepinus, 159 (41.5%) O. niloticus and 61(15.9%) B. intermedius were examined. The length and weight of each sampled fish were recorded. All the sampled fish were examined for the evidence of Contracaecum parasites in Hawassa University Veterinary Parasitology and Pathology Laboratory. Chi-square values and comparison of proportions were used to analyse the data. The overall prevalence of Contracaecum parasites of fish population was 31.6%. The distribution of parasite was significantly affected by fish species (p = .000), sexes (p = .018), length (p = .003) and weight classes of fish (p = .026). As a hygienic problem and gutting activity conducted at the sides of the Lake Hawassa and distribution of discarded fish wastes for surrounding piscivorous birds by butchers and other people, the life cycle of Contracaecum parasite was perpetuated. Thus, the parasite is of zoonotic significance. Therefore, awareness creation activities for societies and control of fish parasites should be conducted in the study area.

Chlorinated organic contaminants in fish from the South China Sea: Assessing risk to Indo-Pacific humpback dolphin

Indo-Pacific humpback (Sousa chinensis) dolphins are primarily exposed to chlorinated organic contaminants through the consumption of contaminated fish. We assessed the potential risk of chlorinated organic contaminants to Indo-Pacific humpback dolphins by determining the concentration of 21 organochlorine pesticides (OCPs) and 28 polychlorinated biphenyls (PCBs) in 14 fish species collected from the South China Sea coastal waters. The results of the study showed that bioaccumulation of OCPs and PCBs was influenced by sampling location, fish species, and fish niche. The average ∑DDT (Dichlorodiphenyltrichloroethane) concentration was 3 times higher in benthopelagic fish (488 ng/g) compared to pelagic-neritic fish (155 ng/g) from Jiangmen, whereas an opposite pattern of the lower DDTs concentration in benthopelagic and demersal fish compared to pelagic fish from Zhuhai (p < 0.05). Furthermore, the molecular diagnostic ratios using DDT and its metabolites (DDT/(DDD + DDE) were less than one, suggesting the DDT contamination at Zhuhai and Jiangmen may due to the historical agricultural usage of the lands. The reference dose-based (RfD) risk quotient (RQ) suggested that DDTs are potential risk in Qinzhou, which is in accordance with the high DDTs concentration found in fishes captured in Qinzhou. The RfD risk quotient of PCBs is at potential risk for all sites (RQ > 100), except Xiamen and Qinzhou. A highest average ∑DDT concentration was observed Qinzhou. This study showed that fish consumption might pose a health risk to Indo-Pacific humpback dolphins. However, further studies are required to determine the contribution of fish niche to the overall risk.

Epidemical study of third stage larvae of Anisakis spp. infection in marine fishes in China from 2016 to 2017

BackgroundAnisakis, a genus of parasitic nematodes, can infect fish and potentially cause diseases in human. Yet it has not drawn public attention in China. It is urgent to conduct the first epidemical study on third stage larvae of Anisakis spp. infection in marine fishes across most coastal regions of China from 2016 to 2017. MethodsIn this study, 2422 samples of marine fishes were collected from eight coastal regions in China from 2016 to 2017. The third-stage larvae of Anisakis spp. were examined under a light microscope. The chi-square test, the Fisher's exact test and the logistic regression were applied in this study. ResultsThe infection rate was 28.70% (695/2422). Compared with live fish, the infection rate of fresh fish was higher at 31.88% (577/1810). Statistical analyses showed that there existed a significant difference in infection rate of different sampling months, which could be explained by fishing ban. ConclusionsThe result showed that sampling region, fish status, fish species and sampling month were the main factors influencing infection rate. Regulations or guidelines are urgent in China for the control of Anisakis spp. infection in marine fish.

Concentration of heavy metals in edible fishes from Atlantic Coast of Muanda, Democratic Republic of the Congo

The present study aims to determine the levels of heavy metals in edible nine different commonly consumed fish species (Pseudotolithus elongatus, Pseudotolithus senegalensis, Cynoglossus senegalensis, Trichiurus lepturus, Galeoides decadactylus, Pentanemus quinquarius, Chrysichthys nigrodigitatus, Mugil curema, and Arius latiscutatus). Fishes were collected during August 2016 from five sites of West Atlantic Ocean Coast of the Democratic Republic of the Congo. Heavy metals (Cr, Cu, Zn, Ni, Sb, Cd, Pb, and Se) levels in fish muscle tissues were determined using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) whereas Hg analysis was carried out using atomic absorption spectrophotometry (AAS). Metal concentrations varied considerably among sampling sites and fish species (P < 0.05), with maximum values (in mg kg−1 wet weight) of 1.00 (Cr), 2.69 (Cu), 29.90 (Zn), 4.25 (Ni), 0.09 (Sb), 0.59 (Cd), 0.09 (Pb), 1.05 (Se) and 1.21 (Hg). Except for Hg, metal concentration in fish was within the permissible levels set by Food and Agriculture Organization, European Union, and World Health Organization for human consumption. However, taking into account the antagonistic effect of Se on Hg, analyzed fishes might have the protection from Hg toxicity. Thus, the results imply that investigated fishes from study area can be considered as safe for human consumption.

Levels, distribution, and ecological risk of organochlorines in red mullet (Mullus barbatus) and annular sea bream (Diplodus annularis) from the Gulf of Izmir, Eastern Aegean, in 2009-2012.

Organochlorine (OCs) concentrations were measured in two fish species, Mullus barbatus and Diplodus annularis, collected from Izmir Gulf during 2009-2012 in order to explain the status of these contaminants in edible fish. No data is available on the levels of organochlorines in marine organism from Izmir Gulf. In both fish species from the study area, Aroclors were determined in higher concentrations than organochlorine pesticides (OCPs). Maximum concentrations of OCPs and PCBs measured in the edible part of D. annularis were 45-165 and 530-1591ngg-1 lipid weight (lw), respectively. DDTs (sum of DDT and metabolites) and cyclodienes ranged from 4-56 to 16-110ngg-1 lw, respectively. The levels of DDTs measured in the present study were generally comparable or lower than those found in studies from other Mediterranean and non-Mediterranean regions. The potential risks for fish consumers were assessed. Although the estimated daily intake (EDI) for DDTs, heptachlor, and drins through the sampled fish species by Izmir inhabitants was quite lower than the ADI (acceptable daily intake) established by the FAO/WHO, EDI for Aroclor 1254 was close to the ADI value of 20ngg-1 recommended by the IPCS (2000).

Polychlorinated Biphenyls in Brackish Water Fish in the River Niger, Nigeria.

Background.Anthropogenic polychlorinated biphenyls (PCBs) in aquatic environments poses human and ecological health risks in Nigeria.Objectives.This study determined the concentrations of PCBs in brackish water fish in the River Niger to assess the contamination status of fish consumed by the local population.Methods.The sampled fish species included Drepane africana, Mochokus niloticus, Chrysichthys nigrodigitatus, Pristipoma jubelini, Vomer septapinis, Pseudotolithus senegalensis, Mugil cephalus, Pseudotolithus elongatus, Sphyraena piscatorum and Lutjanus goreensis, purchased from landing sites. Six fish from each species were sampled, for a total of 60 samples. Twenty-seven (27) PCB congeners, #8, #18 #28, #44, #52, #60, #77, #81, #101, #105, #114, #118, #123, #126, #128, #138, #153, #156, #157, #167, #169, #170, #180, #185, #189, #195, and #206 were screened in the fish samples using standard methods. The PCBs were identified and quantified using gas chromatography (GC) (Hewlett Packard GC 5890 series 11 with electron capture detector). Confirmation was performed using Shimadzu GCMS QP2010.Results.The sum of the National Oceanic and Atmospheric Administration Agency (ΣNOAA) PCBs occurred at the highest concentration of 1830.0±484.0 μg/kg detected in Vomer septapinis, and the lowest in Pseudotolithus senegalensis, with a mean concentration of 795±169.3 μg/kg. The concentration of dioxin-like (DL) PCBs was highest in Pristipoma jubelini (992.0±88.6 μg/kg) and lowest (285.6±81.5 μg/kg) in Drepane africana. The highest mean concentration (418.±177.6 μg/kg) of International Council for the Exploration of the Seas-7 (ICES-7) PCBs was observed in Vomer septapinis. The heavier ICES-7 congeners PCB-138, PCB-153, and PCB-180 occurred at higher concentrations compared to the lighter molecular weight ICES-7: PCB-28, PCB-52, and PCB-101. The European Union (EU) marker PCB limit of 335 μg/kg was exceeded in all the brackish water fishes with the exception of Mochokus niloticus, Pristipoma jubelini and Pseudotolithus senegalensis.Discussion.The total level of PCBs in the brackish fish samples was relatively high at >1000 μg/kg (above the World Health Organization (WHO) and Food and Agriculture Organization of the United Nations (FAO) guideline of 1000 μg/kg fresh weight). The EU guideline value for fish (220 μg/kg fresh weight) was exceeded in about 80% of the brackish fish samples studied.Conclusions.Consumption of fish from the River Niger may expose humans to polychlorinated biphenyls. In addition, since contamination of the fish samples is an indication of river contamination, river water quality is of great concern and there is a need for additional PCB data on water quality to be distributed to the community, followed by mitigation measures.Competing interests.The authors declare no competing financial interests.

Pesticide residues in muscles of some marine fish species and seaweeds of Iskenderun Bay (Northeastern Mediterranean), Turkey.

Pesticide residues in muscles of nine marine fish and four seaweed species of Iskenderun Bay (Northeastern Mediterranean) have been investigated. In sampled fish species, two herbicides, three insecticides, two fungicides, and one synergist were identified and quantified. Metribuzin DADK, propamocarb HCl, and piperonyl butoxide (PBO) were detected in all the muscles of sampled fish species. Metribuzin DADK was the most abundant pesticide residue in fish muscles and the highest metribuzin DADK concentration was found in sardine (311.20μg/kg). Propamocarb HCl concentrations varied greatly among species; from 0.530 ± 0.020μg/kg in striped sea bream to 34.170μg/kg in sea bass. The level of PBO ranged from 0.001μg/kg for fourlined terapon to 0.013μg/kg for sardine. No measurable oxamyl residue was found in any of the muscles of sampled fish species (except sardine). In seaweeds, two herbicides and two insecticides were identified and quantified. Metribuzin DADK was the most abundant and found in Cystoseira corniculata (5.01mg/kg), Corallina elongata (0.703mg/kg), and Jania rubens (3.85mg/kg). Molinate was a minor contaminant and only found in Corallina elongata (0.002mg/kg). Pyrethrin I was determined only in Padina pavonia to be 0.567mg/kg. Pyrethrine II was found in Padina pavonia and Corallina elongate to be 1.214 and 0.229mg/kg, respectively. The most hazardous pesticide residues of organochlorines and organophosphorus were not detected in both sampled fish muscles and seaweeds. There are no clear maximum residue limits for the detected eight pesticide residues declared for fish muscle by European Union MRL (2017). In conclusion, it can be considered that observed concentrations of pesticides in sampled nine marine fish species do not have a potential health risk for consumers. Some of the detected pesticide residues can be toxic for algae and aquatic life and regular monitoring studies are therefore essential to control the pesticide concentrations of aquatic biota in the region.