نشریه پژوهش های ماهی شناسی کاربردی
سال یازدهم شماره 4 (زمستان 1402)

This research was conducted in order to investigate the effect of adding salt and Bacillus subtilis bacteria (IS02) to the diet on the survival, cortisol response and antioxidant indices of sea carp, Cyprinus carpio, under salinity stress. Baby carp fish (average 1.1 g) were fed with diets containing 5 and 10% salt or 108 x 5.2 and 109 x 5.2 colony grams (cfu/g) of probiotics for 15 days and then to They were directly transferred to saline water with a concentration of 13 grams per liter and samples were taken after 3 and 10 days. Survival in all treatments was above 96%. The amount of cortisol at baseline and after salinity stress in probiotic treatments was significantly lower than other treatments. Superoxide dismutase activity was higher in probiotic treatments than other treatments. Diets had no significant effect on catalase activity. Based on the results of this research, the use of B. subtilis in the diet can reduce stress and increase the antioxidant capacity in juvenile Norse carp.

A experiment was carried out to evaluate the effect of four levels of stocking density (30, 45, 60 and 75 fish/m3) on growth parameters and biochemical factors of blood serum of Oncorhynchus mykiss larvae with average mean weight 0.235±0.08 g were stocked in 12 fiberglass tank (10 L) was studied for a period of 45 days. At the end of the experiment, were observed no significant differences between growth parameters and feed efficiency among treatments (p>0.05). However, Analysis of biochemical factors of serum blood showed significant difference between treatments (p<0.05). The highest amount of blood serum of total protein (7.40±0.10), ALT (23.00±1.00) and ALP (243.00±8.18) activity enzymes, amylase (23.66±1.52), lipase (111.00±6.55) and calcium (15.66±0.05), as well as the lowest amount of cortisol (36.00±1.73) and albumin (10.76±0.11) was observed in treatment containing maximum stocking density level at 75 fish larva per m3 (p<0.05). Also, the highest amount of glucose (139.00±5.56) was observed in treatment at 60 fish larva per m3 and the highest AST activity enzyme (7.33±0.57) was observed in two treatment at 30 and 45 fish larva per m3 (p<0.05). Finally, according to the results, an increase in stocking density of O. mykiss larvae cannot be affected the efficiency of fish farming. But, this increasing density had significant effect on immune factors and stressors.

Fish transportation and catching is a common activity in aquaculture that induces stress and immunosuppression. The aim of this study was to investigate the effects of using Sanyar prebiotic (powder and liquid) in biofloc environment on metabolic activity, stress indices, and hematological of common carp (Cyprinus carpio) under catching and transporting stress. Diets containing prebiotic (0.1 and 0.2 g powder; FP1 and FP2) and (1 and 2 ml liquid, FL1 and FL2) and control group without additive (FC) in biofloc system and the control group without additive with clean water (C) were fed to common carp for 60 days. At the end of the rearing period, to simulate catching stress, the fish were followed in the tanks with hand fishing nets for 10 minutes. For stress caused by long transportation with a stocking density of 1 kg (6 treatments and each with 3 replications), plastic bags (20 liters of water and 20 liters of oxygen) were used for 12 hours. After applying stress, blood sampling was done separately from the fish in two groups (catching and transportation). Metabolic activities (hepatic enzymes, urea, and creatinine), Red blood cells, hemoglobin, and hematocrit had a significant decrease in prebiotic treatments under stress. Cortisol concentration in the FC treatment (catch) and in the control treatment (transportation) significantly increased compared to other experimental treatments. In general, the results showed that using Sanyar commercial prebiotics in the biofloc environment reduces the stressful effects of catching and transportation for common carp.

Three species Rutilus frisii, Alburnus chalcoides and Vimba persa are the most valuable fish that migrate to southern Caspian rivers especially Sefidroud river. In this study, the temporal and spatial distribution of was investigated based on presence and abundance of fingerling fish in 8 stations of the Sefidroud River, from the estuary to the Sangar Dam, during one year from March 2021 to December 2022. According to the environmental conditions of stations, the sampling was done with an electrofishing instrument and a throwing net with mesh size 6 mm. The results showed that the abundance of fish fingerlings is minimal in the winter and their maximum abundance coincides with the reproduction time and after their adult spawning. The maximum abundance of these fingerlings along with their spatial distribution, also shows their migration pattern towards the Caspian Sea. The abundance of Rutilus frisii in the pebble and gravel beds of the upstream stations was the highest in April and the abundance of the Alburnus chalcoides and Vimba persa in the gravel-mud beds of the middle stations up to the estuary was the highest in August-September. The presence of Rutilus frisii fingerling, with an average weight of 2 g. was high in near to estuary in August while the other two species were present in the middle stations with high abundance until November. Rutilus frisii with weigh more than 3 grams in different stations in autumn and winter indicate the adaptability and residency of a number of fish in the river. The present study can provide some guidelines to the fish stocks restoration centers of Caspian Sea for releasing Kutum fry in the upstream areas, or fish fingerling in the middle of the river at an earlier time. This plan can be tested in a pilot program.

Blacktip Sea Catfish (Plicofollis dussumieri) is one of the most abundant commercial species along the coast of the Oman Sea. In this study, with the aim of an investigation some biological parameters of Blacktip Sea Catfish using gillnet and purse seine in coastal waters of Sistan and Baluchistan province (Oman Sea). Sampling was conducted from January to March 2020 and 818 P. dussumieri were collected using gillnet and 300 P. dussumieri were collected using purse seine and the fork length range of P. dussumieri was 22.10-62.10 cm and 17.30-10.37 cm in gillnet and purse seine, respectively. The Asymptotic length (L∞) was estimated at 64.41 cm and the optimal catch length was 34.41 cm. The length maturity (Lm50) of P. dussumieri was calculated to be 32.5 cm. The results show 38.10% of the fish caught were immature and did not have a chance to spawn. Most of the P. dussumieri that were caught by purse seine were smaller than length at maturity (Lm50). Obtaining such parameters with studies and long-term planning of these stocks and the information related to the length frequency, Asymptotic length, optimum catchable length and length at maturity can have a great impact on the knowledge of the stocks and fishing pressure on aquatic stocks such as P. dussumieri in Sistan and Baluchistan province.

With the rapid expansion of the aquaculture industry, in order to meet the protein needs of humans, stress and susceptibility of fish to disease in the intensive system has increased. Therefore, the use of many dietary supplements such as feathers probotics, safety stimulants, and plant products have been developed to combat the side effects associated with growing conditions. This experiment was conducted to evaluate the effect of of bioherbal feed supplement on the liver (aspartat amimotrasferase (ASP), alaninaminotransferase (ALT) and alkanin phosphatase (ALP)) and digestive enzymes (amylase, protease and lipase) and chemical parametese (glucose (GLU), cholesterol (CHO), triglyceride (TRI), total protein (TP), albumin (ALB) and globulin (GLO) of Mugil cephalus for 60 days. The experiment was conducted in a completely randomized design with 450 of grey mullet larvae (with average weight of 0.72±0.01g) in 5 treatments and 3 replicates (n=30 in each replicate) and included: control group without using bioherbal, an another groups (treatment 2, 3,4 and 5) the amounts of this herbal supplement were 5,10,15 and 20 g/kg food. At the end of experiment , the results showed that the highest the activity of protease (341±12.08U/mg protein), amylase (404.67±11.23 U/mg/protein) and lipase (5.76±0.18 U/mg protein), the lowest ASP (92.66±13.05U/mL), ALT (15.33±1.15 U/mL) and ALP (66.33±2.51 U/mL) enzymes were observed in the diet containing 20 g /kg bioherbal supplement in all of these parameters, treatment 5 (20 g/kg) (4) showed a significant difference compared with control treatment (P<0.05). Also, the lowest serum CHO (120.66± 3.78 mg/dL), GLU (80.33± 1.57 mg/dL) and TRI (120.06±9.01 mg/dL), the highest GLO (1.52±0.15 g/dL) were recorded in treatment 4. Finally, the present results suggest that diet containing 20 g/kg bioherbal supplement (ginger and fennel powder) could improve digestion and liver function index enzymes and biochemical parameters of Mugil cephalus larvae.

Freshwater fishes have great importance in freshwater ecosystems and play various roles in ecosystems. Measuring the biodiversity of these fish is a key focus in many ecological studies. The measurement of biodiversity depends on the type of data and the study objectives and various methods have been developed to calculate it. This study aimed to calculate the biodiversity of fish in the Lake Urmia basin using fractal analysis based on fish presence data. Additionally, the calculated fractal dimension was obtained with simulation, which determined the range of fractal dimension variations. The results indicated that the fractal dimension of freshwater fish in the Lake Urmia basin is at an average level. Considering the drying of Lake Urmia, these results suggest that the biodiversity of these fish is highly sensitive and may tend towards negative changes. The average level of biodiversity among fish in the basin can also indicate an average level of population connectivity and gene flow. The methodology used to study biodiversity and its changes can be applied to other aquatic ecosystems and watersheds. These findings highlight the importance of conservation efforts and further research to mitigate potential negative impacts on freshwater fish populations and their ecosystems.