Bioaccumulation of heavy metals Cu, Zn, and Hg in muscles and liver of the stellate sturgeon (Acipenser stellatus) in the Caspian Sea and their correlation with growth parameters

Bioaccumulation of Cu, Zn, Hg in muscles and liver tissues of stellate sturgeon (Acipenser stellatus) from the southern Caspian Sea was measured. Effects of condition factor (CF), age and hepatosomatic index (HSI) on metal accumulation were also determined. Some 40 stellate sturgeons were collected using gill nets in winter and spring 2007-2008 from the southern shores of the Caspian Sea. Total (TL) and fork (FL) length and weight of all specimens were measured. Cross sections of first ray of pectoral fins were used for age determination. Muscle and liver samples were taken and transported to the laboratory in ice packs and kept in -20 °C prior to analyses. In the laboratory samples were oven dried, digested with HClO3 and HNO3 and diluted with dionized water to 50cc to measure Cu, Zn, and Hg concentration with a flame spectrophotometer. Sequence of metals in Acipenser stellatus was Zn>Hg> Cu in muscle tissues and Zn>Cu>Hg in liver samples. Concentration of Zn was slightly in correlation with age (R= 0.3). A negative correlation was observed between Zn concentrations with condition factor (R = -0.3). Zn concentrations were negatively correlated in muscle tissues (R = -0.3). The results were compared to international standards proposed by MAAF, EEC and NHMRC. Our study showed that accumulation of heavy metals in sturgeon tissues was influenced by concentration of metals in sediment and the physiological state of fish

Concentration of heavy and toxic metals Cu, Zn, Cd, Pb and Hg in liver and muscles of Rutilus frisii kutum during spawning season with respect to growth parameters

Concentration of heavy and toxic metals Cu, Zn, Cd, Pb and Hg were determined in liver and muscles of Rutilus frisii kutum and their relationships with growth parameters (length, age, condition factor) and hepatosomatic index were examined. Thirty-six fish samples were collected from February through March 2009 caught by beach seine in the southwest parts of the Caspian Sea. Atomic absorption and Hg determined concentrations of Cd, Pb, Zn and Cu by vapor method. Cadmium was recorded only in liver samples. Range of other metals in muscle tissue were ND-0.591, 0.001-0.013, 11-26 and 0.729-7.261 µg/g dw for Pb, Hg, Zn and Cu respectively. Highest levels of Pb, Zn, and Cu were recorded in muscles Hg and Cd in liver samples. Growth parameters showed a significant relationship with Zn and Cd concentrations in liver samples and only Zn concentrations in muscle samples. There was a positive significant correlation between concentration of Cd in liver and physiological indices (p<0.05). Although higher concentration of Pb was recorded in this study in comparison to previous studies, based on Provisional Tolerable Weekly and daily Intake of fish for human health, kutum is considered safe for human consumption. Considering the results of this study it seems reproductive status of the fish influences heavy metals concentration in liver and muscles of kutum and therefore concentrations of some metals such as Zn and Cu in liver samples may not be a reliable bioindicator for environmental pollution

Benthic macroinvertebrate distribution in Tajan River using canonical correspondence analysis

The distribution of macroinvertebrate communities from 5 sampling sites of Tajan River were used to examine the relationship among physiochemical parameters with macroinvertebrate communities and also to assess ecological classification system as a tool for the management and conservation purposes.The amount of variation explained in macroinvertebrate taxa composition is within values reported in similar studies. Results of CCA ordination showed that the dissolved oxygen, water temperature, turbidity, pH and TSS were the most important physicochemical factors to affect distribution of macroinvertebrate communities. The study revealed that macroinvertebrate communities of Tajan River may be explained by physiochemical parameters. Mean values of Shannon–Wiener diversity index calculated for macroinvertebrates ranged from 1.35± 0.07 (S5) to 1.86± 0.10 (S1). According to the Shannon–Wiener diversity index the S1 sampling site was categorized in ‘‘good‘‘ and the sampling sites S2 and S3 in ‘‘moderate’’ and S5 in ‘‘moderate to substantially polluted” classes. The anthropogenic disturbances (e.g. trout farms and effluents from factories) impacted abundance and diversity of macroinvertebrate

Assessment of fish farm effluents on macroinvertebrates based on biological indices in Tajan River (north Iran)

Impacts of effluent from fish farming activities on fluvial ecosystems lead to deterioration of water quality and changes in the macroinvertebrates assemblage. In this study, the influence of fish farm effluents on water quality and macroinvertebrates communities of Tajan River was investigated to evaluate the suitability of macroinvertebrates based on biological metrics and indices. Benthic macroinvertebrate communities were analyzed seasonally for a period of one year . Five sampling stations were selected along the study reach of 50 km. Station 1(S1) which is located upstream from the fish farm, was used as the reference site. Station S2 and S3 were located downstream from the fish farm outlet; S4 and S5 were further downstream. In order to assess the changes in diversity and richness in relation to water quality,two major groups of sites based on similarity between macroinvertebrate communities identified by cluster analysis. Diversity of macroinvertebrates, EPT richness and EPT/CHIR indices significantly decreased toward downstream stations except for station S4. Conversely, values of HFBI and Jacard index significantly increased in the downstream stations. The present study revealed significant differences in water quality parameters between the stations located above and below the fish farms. Owing to the relatively high diversity of benthic macroinvertebrates inhabiting rivers, use of macroinvertebrate based biological indices is recommended for assessment of water quality and pollution in fluvial systems

Heavy metals Cu, Zn, Cd and Pb in tissue, liver of Esox lucius and sediment from the Anzali international lagoon- Iran

Levels of contaminants in fish are of particular interest because of the potential risk to humans consuming them. This paper examines the levels of cadmium, lead, zinc and copper in liver and muscle tissue of Esox lucius and in sediments from the Anzali international wetland in Iran. The wetland is a nursery and feeding habitat for fish species both from the lagoon and the Caspian Sea, which are consumed by the local inhabitants and others. Eleven main rivers discharge agricultural, industrial, urban and municipal wastes into this wetland. Twenty five Esox lucius specimens, with a mean weight of 804.6±121g and mean length of 430.7± 2mm were collected from the wetland by multi mesh gill nets in September and December 2007.. The age was determined from scale samples according to the annual ring structure. Average concentrations of Cd, Cu, Pb and Zn accumulated in the mid-dorsal muscle tissue (filleted and skinned) of fish were 0.001, 0.21±0.02, 0.13±0.01 and 2.55±0.18 µg.g-1, respectively. The concentrations of these metals in liver samples were Cd: 0.0014± Cu: 0.96± 0.61, Pb: 0.11 ± 0.04 and Zn: 2.46±1.5 µg.g-1. Significant positive correlations were detected between Zn and Cu with body weight, while negative correlations were found between Pb and body weight. The concentrations of Zn, Cu and Cd were below the maximum allowable concentrations for fish proposed by WHO and MAFF (safe for human consumption) but concentration of Pb exceeded the standard levels

Histopathological changes in liver and gill of Acipenser persicus fry in short term exposure to Nodularia spumigena

Persian sturgeon, Acipenser persicus is a native, commercially important and highly steemed fish species in the Caspian Sea. In this study, effects of Nodularin (NODLN), a cyclic pentapeptide hepatotoxin, on liver and gill tissues of A. persicus were studied. Nodularin was produced in high amounts by Nodularia spumigena, a cyanobacterium species during the algal bloom in the Caspian Sea and was accumulated in biota of the Sea. Persian sturgeon were exposed directly to NODLN as prolonged immersion containing N. spumigena in two different doses (1×104 and 1× 108 cells.ml-1) for 24, 48 and 96 hours to examine its histopathological effects on fish liver and gill. Histopathological examinations revealed loss of liver architecture, degeneration of hepatocytes, nuclear pyknosis, karyolysis and finally necrosis of the cells over the time. Observation of gill tissues following immersion in algal cells treatments showed hypertrophy, fusion of secondary lamellae due to proliferation (hyperplasia) of branchial epithelium in low dose and vacuolization of epithelial and pilar cells, tellangiectasis, fusion of secondary and primary lamellae, complete necrosis and sloughing of secondary lamellar epithelium in high dose

Length-length, length-weight relationship and relative condition factor of pike, Esox lucius Linnaeus, 1758, in Anzali Wetland (Southwest of the Caspian Sea)

The length-length (LLRs), length-weight (LWR) relationships and relative condition factor (Kn) of 505 specimens of pike, (Esox lucius Linnaeus, 1798) from Anzali Wetland, southwest of the Caspian Sea, were studied from April 2012 through March 2013. The length-length relationships among total length (TL), fork length (FL) and standard length (SL) for pike were found to be highly significant (r2>0.986, P<0.001). The values of b in length-weight relationship in males (3.1495), females (3.1843) and for all specimens (3.2137) indicated isometric growth. Mean relative condition factor for male, female and all specimens were 1.003, 1.004 and 1.008 respectively. The result of LWR could be used for fishery managers to approve appropriate regulations for sustainable fishery management. Few studies have been conducted on these parameters of pike and this is the first report on LLRs, LWR and Kn of pike from Iranian waters

Effects of Substrate Type on Benthic Diatom Assemblages of a Masooleh Rud River – Guilan

The present study was conducted to evaluate the effects of some physical and chemical parameters of water e. g. pH, temperature, electron conductivity (EC), Fe, silicate, orthophosphate, Nitrate on diversity and abundance of periphyton diatoms in a tributary of the Masooleh River (located 37o 22’ to 37o 23’ northern latitude and 49o17’- 49o19’ eastern longitude in Guilan Province, north of Iran) in summer, autumn and winter, 2011. The study area was 15 km in area, and 5 sites were chosen for diatom sampling. The average depth of the river was 0.5 m with temperature ranging from 14 to 31 0C. Elevation from the sea level and all parameters mentioned above were measured for each sampling site. The samples were collected from surface layer of Epilithon, Epidendron, Epipssamon and Epipelon as natural substrates. The results showed the following ranges: EC: 617-1370 S.cm.-1 pH: 7.82- 8.81 and nutrients: PO43-: 0.02- 0.21mg.l-1, NO3: 1.2- 3.5 mg.l-1, SiO2: 0.02- 6.5 mg.l-1and Fe2+ < 0.02- 0.1 mg.l-1 as an indicator of trophic status of the river. The collected samples were processed and slides were prepared for LM examination. In this study, 23 genera of diatoms were identified. The least and most abundant diatoms were observed on muddy (12.52) and stony (30.86) substrates, respectively. Comparison of mean abundance of diatom population on different substrates (muddy: 23.95± 4.08, gravel: 15.52± 0.97, woody: 17.71± 0.62 and stony: 23.95± 4.08) revealed statistically significant differences between stony, gravel, muddy, and woody substrates (P<0.05). The distribution of diatoms on coarser substrates (wood, stone and gravel) was higher than on softer ones (muddy). Based on the obtained results, woody and stony substrates seem to be more suitable for ecological monitoring of streams than muddy and gravel substrates

Reproductive biology of Caspian vimba, Vimba vimba (L.), in the coastal waters of the southwestern Caspian Sea

The reproduction biology of Caspian vimba, Vimba vimba (L.), was investigated on the southwestern coast of the Caspian Sea using 712 fish specimens collected at three fisheries catch stations located in Talesh, Anzali, and Kiashahr over a two-year period from April 2012 through June 2013. Seasonal changes in the gonadosomatic index, gonad histological status, size frequency distribution of oocytes, and the fecundity of the species were studied. The peaks of the gonadosomatic index (GSI) were observed both in females and males in June 2012 and May 2013 indicating the variable peak spawning time of this species. Histological examinations and oocyte frequency distribution patterns showed synchronous oocyte development in the Caspian vimba. Absolute fecundity ranged from 5873 to 35421 eggs. The size at first maturity for females was 120 mm FL. We concluded that the Caspian vimba is a total spawner with variable spawning dependent on environmental factors

Reproductive characteristics of northern pike, Esox lucius (Actinopterygii: Esociformes: Esocidae), in the Anzali Wetland, southwest Caspian Sea

Background. Temporal variability in fish reproductive features is influenced by environmental and spatial variations. Given the wide distribution of northern pike, Esox lucius Linnaeus, 1758, in the northern hemisphere, important reproductive features such as the initiation of the spawning activity are likely to vary with latitudinal gradients. The overall goal of the presently reported study was to answer basic questions regarding the reproductive biology of the pike and to discuss changes in the timing of the onset of spawning activity in relation to geographical locations and the water temperature in the Anzali Wetland compared to higher latitudes. Materials and methods. Monthly samples (537 specimens in total) were collected from the Anzali Wetland (southwest of the Caspian Sea) from July 2012 through July 2013. Samples were macro- and microscopically examined, and their maturity stages were identified, so that spawning season, monthly distribution of maturity stages, oocytes development, spawning strategy, length at 50% maturity, and fecundity were estimated. Results. The gonadosomatic index, oocyte size-frequency distribution, and histological examination suggested a relatively short spawning season, from February through March. The short annual spawning period and the oocyte size-frequency distribution demonstrated that pike is a total spawner with group synchronous oocyte development. The length at 50% maturity was 28.5 and 33.9 cm FL for males and females, respectively. Absolute fecundity values ranged from 4423 to 48471 oocytes, with mean (± standard error) of 16481 ± 2705 oocytes and the relative fecundity was estimated as 26.9 ± 1.6 oocytes per gram of mature female. Conclusion. The most important findings of this study are: the earlier initiation and relatively shorter duration of the reproductive activities of pike in the south Caspian region compared to northern geographical regions. The results emphasize the need for specific management strategies based on seasonal measures for pike such as: fish size limits, limitation of catches during the spawning season, limitation of the boat number, and closure of the spawning area during spawning months