جستجوی مقالات مرتبط با کلیدواژه « Caspian kutum » در نشریات گروه « محیط زیست »

The Caspian kutum is a economic precious species in Caspian sea. It is very important to maintane the nutrition value with increasing of shelf-life until marketing. Determining the best method of slaughtered in this species and proper marketing of fish with acceptable freshness in the consumer market are the main aims of this study. 4 treatments including fish with rapid death (due to branch cut) with visceral emptying (treatment 1), rapid death without visceral emptying (treatment 2), common death with visceral emptying (treatment 3) and common death without visceral emptying (Control treatment, 4) all  stored in ice. and from phase 0 to 16 days were evaluated for freshness by performing qualitative tests. The results showed that the fish entered the rigor mortis stage at a later time in emptying the visceral and rapid death method and left later than other treatments. Also, the amount of TVN-N in this treatment reached an acceptable level of 19.26 mg / 100 g by day 8 and the amount of TBArs reached 1.5 mEq of malon dialdehyde/1000 g, the pH of the treatments from 5.75 to 5.76 were variable. The most total bacterial count was observed in control treatment (6.6 log cfu/g). Primary processing in post harvest is effective on quality parameters. In terms of freshness evaluation in the (treatment 1) until the 8th day was acceptable in all quality indicators, but other treatments before that were spoiling and exceeded the acceptable level.

Microplastics exists in marine habitats all over the world, and laboratory studies show that, this substance can be swallowed up by fish and transmitted through human consumption of fish. However, data on its abundance in lakes are limited. The purpose of this study is to determine the amount of micro-plastic accumulation on Caspian kutum as a seafood. This study was carried out on 51 whitefish collected during the fishing season (February to March) 2017 at six stations (Gomishan, Babolsar, Mahmoudabad, Tonekabon, Chamkhaleh, Bandar Anzali) on the southern shores of the Caspian Sea. The results showed that in the gastrointestinal tract, 66.6% of the fish were micro plastics. On average, each fish was swallowed by 1.47 pieces of micro plastics the most of these micro plastics were fibers (38.75%), then fragments (42.31%), films (30%) and beads (11.42%). These data show that there is a significant amount of micro plastics contamination in the Caspian Sea fish. The consumption of this fish may transfer micro plastic to humans. The results of this study were compared with reports from other parts of the world indicating that more study in the Caspian Sea should be conducted.

Seafood are considered as the important sources of high-quality protein, but they can contribute significantly to human dietary risk. The aim of the present study was: detecting of the concentrations of cadmium (Cd) in skin and muscle tissues of rutilus kutum; comparing the concentration of Cd in tissues of male and female; and finally assessing the food consumption risk in southern coast of the Caspian Sea. The thirty specimens of Caspian kutum were obtained from southern coast of Caspian Sea. After digestion of specimens, concentration of Cd were detected by atomic absorption spectrophotometer. The mean concentration of Cd in skin and muscle tissues were 0.45±0.38 and 0.38±0.06 µg/g wet weight, respectively. The result of statistical analyze showed deference in Cd concentration in skin and muscle tissues (p<0.01). Also, there was no any significant deference in Cd concentration between male and female. THQ (2×10-4) was lower than allowable dose proposed by EPA. Daily and weekly intake of Cd in edible tissues were 1.42 µg per day and 9.97 µg per week, respectively, that showed that the estimated amount of Cd intake is lower than the maximum acceptable level permitted by the joint FAO/WHO expert committee. The maximum allowable consumption rate for adults and children were 0.16 and 0.03 kg per day, respectively. The maximum allowable consumption rate in meal were 21.79 and 4.51 meal per month for adults and children, respectively. The present study showed that Caspian kutum meat is safe to consume and does not threaten the health of consumer with current consumption rate.

Habitat loss is one of the most serious threats to the recovery of fish stocks and can jeopardize the ability of marine coastal areas to support artisanal fisheries. On the other hand, habitat species modeling is a practicable solution for conservation and protection of marine ecosystems and habitats. In the present study, species suitability modeling was applied to determine habitat of Caspian kutum in southern Caspian Sea that five environmental variables include depth, chlorophyll a, photosynthetically active radiation, sea level anomaly and sea surface temperature were used. The results show that the most habitat suitability of Caspian kutum was in southwest Caspian Sea (include 8c, 25 and 15b indices) and depth and chlorophyll a are the most important environmental variables for the Caspian kutum to modeling its habitats. The results of accuracy assessment for weighted scenarios show that best scenario considering the AUC ROCs of 0.69. According to suggests that output of present study used a criteria for identifying marine protected areas, site selection of aquaculture and others Ecosystem Services Models in southern Caspian Sea.

To determination the toxic effects of atrazine on Caspian kutum, the 96-h LC50 of atrazine was measured for newly hatched larvae as 18.53 ppm. Toxicity of atrazine herbicide on Caspian kutum larvae was investigated using concentrations: 9.25ppm, 4.62 ppm and 2.31 ppm for 7 days. Comparison of the length, weight and condition factor showed that no significant differences between atrazine exposed and control groups. The concentration of Na+, K+, Ca2+, Mg2+ and Cl- in whole body of larvae in control and atrazine exposure groups were measured and the results showed that concentrations of all these ions is higher in atrazine exposure group than control group. Results of the present study showed that atrazine could affect the ion compositions of the body even at sublethal concentration and acute exposure but at this kind of condition have no effects on growth parameters of the body.