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Alosa braschnikowi and Vimba persa are commercially important fish species in the southern part of the Caspian Sea. However, little is known about the trace element (TE) concentrations in their muscles. To this end, a total of 82 pieces of V. persa and 74 A. braschnikowi were caught at three different fishing areas (Astara, Anzali, and Kiashahr) around the southwestern shorelines of the Caspian Sea from September 2017 through June 2018. An inductively coupled plasma optical emission spectrometry (ICP-OES) was used to measure the accumulation of 34 traces and macro elements in some tissues of the fish species. Then, comparisons of the element levels in these tissues were made for the three different fishing areas. Overall, in the case of A. braschnikowi, 30, 30, and 28 elements were detected in its skin, gonads, and kidneys, respectively, while in the case of V. persa, 27 and 28 elements were found in its muscle and liver, respectively. The majority of element levels measured in these tissues indicated no significant differences among the sampling areas (P>0.05) except for such elements as copper, lanthanum, and tungsten in skin, lanthanum, rubidium, and vanadium in gonads, as well as molybdenum and zinc in kidney (P

The trace elements (TEs) in aquatic environments due to anthropogenic activities are readily available to aquatic organisms. There are 153 fish species inhabiting the Caspian Sea. However, little is known about TE (TE) concentrations in these species. In this study, we investigated the effects of TEs levels in the brain of some bony fish species inhabiting the Caspian basin. Totally, 405 fish from nine species with different feeding behaviors including Leuciscus aspius (n = 20) and Perca fluviatilis (n = 37) as piscivores, Rutilus kutum (n = 27) and Rutilus caspius (n = 71) as carnivores, Vimba persa (n = 56), Ponticola caspia (n = 25) and Tinca tinca (n = 31) as mollusivores, and Alburnus chalcoides (n = 77) and Alosa braschnikowi (n = 61) as zooplanktivores were collected from the southwest of the Caspian Sea basin from September 2017 to June 2018. The ICP-OES was used to measure TEs in the brain tissue of fish. The variability of TEs concentrations in the brain tissues of these fishes by principal component analysis (PCA) was decreased to 63.59% and 17.68% for PC1 and PC2, respectively, exhibiting that 81.27% of the total variability is associated with K, Mg, P, S, Zn, and Al. The two-dimensional diagrams showed the weight of each component in PCA. The PC1 was mostly influenced by P, Mg, K, and Zn, while the greatest value in PC2 belonged to Al. Furthermore, the entire number of elements determined in this study was found to be a suitable indicator for the distinction between fish species based on their feeding items.

Background: Herbicides are usually used to control weeds and some of them like glyphosate are nonselective herbicides. Aquatic environments are usually the last destinations of agricultural pesticides, which disrupt the metabolic processes of organisms. Thus, the aim of this study was to evaluate acute toxicity of glyphosate on the survival rate of common carp, Cyprinus carpio. Methods: A total of 135 common carp averaged 7 ± 0.8 g in weight were exposed to 0, 25, 50, 75, 100, 125, 150, 175 and 200 mL.L-1 glyphosate (15 fish in each treatment, with triplicates) for 96 hours. The aquariums capacity was 98 L in volume (80 × 35 × 35 cm) and physicochemical parameters were the same for all groups (pH 7.4-8, temperature = 26 ± 1oC, DO = 7 mg.L-1 and total hardness of 190 mg CaCO3). LC10, LC20, LC30, LC40, LC50, LC60, LC70, LC80, LC90 and LC95 of glyphosate were calculated at 24, 48, 72 and 96 hours after adding glyphosate using probit test. Results: Mortality was observed in all treatments which exposed to higher than 50 mL.L-1 after 96 hours. The results showed that 96-hour LC50 of glyphosate for common carp was 92.71 mL.L-1. The fish exposed to different concentrations of glyphosate showed clinical signs such as increased mucus secretion, skin darkening and death with mouth open. Conclusion: Glyphosate disrupts the synthesis of amino acids in plants by inhibiting enzymatic activity of 5-enolpyruvylshikimate-3-phosphate synthase (EPSP). This enzyme is absent in animals. However, glyphosate is toxic for common carp. Keywords: Animals, Herbicides, Glyphosate, Carps, Excitatory postsynaptic potentials