نشریه آبزیان دریای خزر
سال چهارم شماره 2 (پاییز و زمستان 1398)

The present study intends depicting of the future sight of Iranian sturgeon relying on economic utilization. This crucial issue would be necessary to rehabilitate the vanishing stocks of these species in the Caspian Sea and Iranian caviar brand around the world. To achieve this goal, a semi-structured interview was conducted with 20 managers and experts of the specialized agricultural service company at different levels were selected by a targeted method with a maximum difference in their overview. Then, the questionnaire of designing model was implemented. Furthermore, the documents and resources related to sturgeon and caviar, the websites of the Iranian fisheries organization and the specialized agricultural services company was investigated. Afterward, the concepts were identified by analyzing the content of oral and written resources, and they were classified to two principal factors including natural stocks and aquaculture development, six main factors such as management system, enhancement the fry production, restriction of pollution releasing, accentuation on structural issues, emphasizing on scientific-technical issues and standardization, plus 73 sub- factors. In the final stage, validity and reliability of the model were confirmed and a future delineation model of these valuable stocks with emphasis on economic exploitation was designed and presented.

Fish protein hydrolysate (FPH) from lizardfish (Saurida tumbil) using papain enzyme at two concentrations of 2 and 4% at two hydrolysis times of 90 and 180 min was prepared and its antibacterial and antioxidant activity were evaluated. The antibacterial activity of FPH against pathogenic bacteria including Escherichia coli, Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Streptococcus iniae and Pseudomonas aeruginosa at different concentrations of peptide (2.34, 4.68, 9.37, 18.75, 37.5, 75, 150, 300 and 600 mg / ml) were studied using agar disc diffusion method. Also, the antioxidant activity of FPH was investigated by measuring DPPH, ABTS and OH free radical scavenging activity. Hydrolyzed proteins by the papain enzyme did not show any antibacterial activity against studied bacteria even at the highest studied FPH concentrations (3300 and 600 mg/ml). Protein hydrolysates showed remarkable antioxidant activity and the highest DPPH (43.72%), ABTS (78.64%) and OH (46.03%) free radical scavenging were observed respectively in 4% enzyme and 180 min treatments. The hydrolyzed protein of Saurida tumbil did not show antibacterial activity, but it can be considered as a natural antioxidant.

, Cheshmehkileh River and its branches in the southern Caspian Sea region display an important role in migration and breeding of Caspian fishes. In this study the hydro chemical parameters were monthly sampled in 13 stations. The results showed that the mean values of water temperature, Electrical Conductivity and pH were 12.2±4.7 ºC, 369±67 μS/Cm and 8.24±0.16, respectively. The mean values of total Hardness, Dissolved Oxygen, Phosphate, N-Nitrate. N-Nitrite, Bicarbonate were 185±25, 9.7±0.9, 0.024±0.029, 0.567±0.284, 0.006±0.006 and 183±68 ppm, respectively. Some parameters such as Ca, Mn, CO3, HCO3, CO2 and Chloride were not significantly different between stations (p>0.05). The water quality index (NSFWQI) varied between 63 and 75 in different stations. According to WQI, Cheshmeh Kileh River was classified as poor to good water quality. The environmental considerations are recommended to decrees of pollutant sources along Cheshmehkileh Rive

In the present study, the feasibility of producing superfine fried fish using Carboxymethyl cellulose coated and Anethum graveolens extract was studied. For this purpose, control samples (without any additive), treatment 2: Carboxymethyl cellulose)18 g (, treatment 3: Carboxymethyl cellulose + Anethum graveolens extract 500 ppm, treatment 4: Carboxymethyl cellulose + Anethum graveolens extract of s 1000 ppm and treatment 5: Carboxymethyl cellulose + Anethum graveolens extract of 2000 ppm. Oil absorption, moisture content, peroxide value and Sensory analysis of fried fish were evaluated. The results of physicochemical test showed that Carboxymethyl cellulose + Anethum graveolens extract increased the moisture content and reduced the fat absorption of oil compared to control treatment, and also more effective to delayed lipid oxidation in fried fish fillet by decreasing peroxide. The best results in relation to these parameters were observed in treatment 5 and then in treatment 4. Sensory score of treatment 4 was higher than the sensory rating of treatment 5. In conclusion, the results of this study indicate that the use of Carboxymethyl cellulose and Anethum graveolens extract with a concentration of 1000 ppm can improve the organoleptic properties and oxidation spoilage of Bighead carp (Aristichthys nobilis) fried fillet.

Natural antioxidants have received much attention due to consumer health and food safety. These antioxidants are found in fruits, plants and bioactive peptides. This paper is going to study the extracts hydrolyzed protein of rainbow trout (Oncorhynchus mykiss) using alkalase and flavorzime enzymes and investigates its antioxidant properties. The antioxidant activity of the hydrolyzed protein was calculated using DPPH free radical scavenging assay and iron ion reduction assay. The results showed that the protein hydrolyzed by alkalase and flavorzime had antioxidant activity and the flavorzime enzyme was able to produce higher protein hydrolysis than the alkalase enzyme. The DPPH radical scavenging ability of the protein hydrolyzed by alkalase was significantly higher than flavorzime (p<0.05). The study of iron reduction power showed that the protein hydrolyzed with flavorzimm had higher reduction power than alkalase (p <0.05). Therefore, the hydrolyzed proteins (less than 3KD) prepared from skin Rainbow trout can be considered as a natural antioxidant.

Heavy metals have a long half-life in the environment. They have the ability to transfer into the food chain. Therefore, their increase (because of mainly discharge of wastewater to aquatic ecosystems) is important for fish and other aquatic organisms. Due to the importance of Cyprinus Carpio fish in food basket of the people in the north part of Iran, this study intends to determine the amount of consumption of this fish without hazards to health, based on the amounts of lead (Pb), cadmium (Cd), and total mercury (Hg) in the muscle tissue of Cyprinus Carpio fish. 45 fish samples were collected at several fishing seines cooperation in the eastern part of the southern Caspian Sea. After the preparation of the muscle tissue, the amounts of Pb, Cd and Hg were measured by atomic absorption instrument. The heavy metals concentration was in order of: Hg >Pb>Cd. Mean concentration (±SE) of Pb, Cd and Hg were obtained 0.089±0.01, 0.013±0.002 and 0.411±0.09 μg/g.dw, respectively. The accumulation of lead, cadmium and total mercury in the muscle tissue of Cyprinus Carpio were in the range of EC, WHO, FDA and FAO safety standard levels. Target Hazard Quotation (THQ) indicated that all metals were in standard threshold in muscle tissue of Cyprinus Carpio and Hazard Index (HI) was recorded below the hazard level. Based on this study, consuming 123 grams per week of muscle tissue of Cyprinus Carpio for adult person do not lead to significant health risk