نشریه پژوهش های ماهی شناسی کاربردی
سال نهم شماره 3 (پاییز 1400)

This study aimed to investigate the effects of different alkalinity levels on growth performance, carcass analysis and blood parameters of kutum fingerlings. The examined fish samples were reared in five levels of alkalinity including a Hall water (control) with an alkalinity of 250 mg/l, 50% distilled water+50% Hall water (110 mg/l alkalinity), Hall water + 10 g sodium bicarbonate (soda, 350 mg/l alkalinity), Hall water + 20 g sodium bicarbonate (450 mg alkalinity), and Hall water + 30 g sodium bicarbonate (550 mg alkalinity) with three replications for 8 weeks. Results of the present study showed that with increased concentration of backing soda, levels of water pH, salinity, EC and TDS increased. Concentrations of ammonia and nitrate in water increased followed by increased concentration of backing soda and the lowest ammonia and nitrate levels were recorded in the treatment containing 110 mg/l CaCO3 and treatments with no backing soda addition, respectively (P<0.05). Contents of blood glucose and serum cortisol increased significantly with increasing soda-induced alkalinity. Changes in alkalinity level did not led to any significant changes in growth performance and feeding indices of the fingerlings. The increased level of backing soda significantly elevated the contents of hemoglobin, hematocrit, red and white blood cells. Results of carcass analysis detected significant differences among various treatments. Considering the non-significant differences among treatments with respect to growth indices, it can be concluded that this valuable species can be farmed in waters with alkali conditions similar to the present study.

Golden barb, Carasobarbus luteus (Heckel, 1843), belongs to the Barbus genus and is one of the freshwater species of Iran and native to Shadegan wetland. Some biological characteristics of Carasobarbus luteus were studied in Shadegan Wetland. Monthly samples were collected from five stations; Doragh (Mahshahr), Rogabe, Khorosy, Salmane and Atish from April 2013 to Mars 2014. 1608 specimens (276 males and 1332 females) were collected and measured. Results showed Mean±s.d length values for the male and female were calculated as 161±28(110-222), 174±38(95-280) mm respectively and mean±s.d weight values were 60±31(15-175), 80±39(15-370)g respectively. The length-weight relation were calculated as W=0.00003L2.83 (R2=0.84) for males, and W=0.0001L2.80 (R2= 0.86) for female; that determined negative allometeric model. The mean values of condition factor (K) were 1.77± 0.14 in males and 0.78± 0.27 for females and have no significant different (P>0.05). The spawning peak was determined in April, and length at maturity (LM), consume per biomass (Q/B) and production per biomass (P/B) were calculated for males and females as below LM=152, 139 mm; P/B= 0.71, 0.52 and Q/B=15.41, 12.37 respectively.

With the increasing use of water resources, increasing population, urbanization, identification and conservation of aquatic ecosystems have received much attention. To this end, researchers consider the use of remote sensing techniques and GIS to be appropriate and efficient. In this study, habitat susceptibility of fish to the Choghakhor wetland in the central plateau of Iran was investigated. After integrating layers of effective parameters (chlorophyll a and water surface temperature), the final map was obtained based on fuzzy logic in Arc GIS 10.3. To better evaluate the final map, it was divided into five classes of very low, low, medium, high and very high potential. Areas that are closer to blue have a higher potential for nesting and fish life, and as we get closer to yellow, their potential is diminished. This study demonstrated the ability of the fuzzy method and remote sensing techniques and geographic information systems to distinguish and identify susceptible areas.

Aquaponic is considered a sustainable semi-closed system for food production that combines aquaculture and hydroponics. The aims of this study were to evaluate the influence of aquaponic on the growth and feed performance, digestive enzyme activity and blood parameters of Common carp juveniles for 60 days. This experiment consisted of three groups (three replications per group) which included; cultivation of common carp without plants (T0), use of aquaponic system for culturing common carp with lettuce (TL) and cucumber (TC). A total of 225 carp (initial body weight: 11.59 ± 0.41g) were randomly distributed in nine 60-L tanks. Results showed that aquaponic system in TL and TC groups could increase the weight gain (WG) and specific growth rate (SGR) and reduce the feed conversion ratio (FCR) of common carp. Total protease, amylase, and lipase activities were also significantly higher in TL and TC groups than control group, respectively. After 60 days, serum lysozyme activity and total immunoglobulin were significantly higher and serum cortisol and glucose levels were lower in aquaponic groups than the control group. The highest serum catalase and superoxide dismutase were observed in TL and TC group. The best effect on growth, digestive enzymes, and immune response were shown in TL and TC groups (Aquaponic system) compared to control.

The present study was performed to measure heavy metals (Pb, Zn, Cd and Cu) in the muscle, liver, gonad, intestine and digestive parasites of Pike (Esox lucius) in Anzali wetland. For this purpose, 90 fish Pike were sampled from Anzali wetland during 2020 and in the reproductive season (winter). During the experiment, total length, fork length, standard length and total weight were measured. The age and sex of the fish were also determined. After emptying the viscera, muscle tissue, gonads, intestines, liver, and parasites were isolated. Then, chemical digestion and metal analysis were performed. The results showed that liver (especially copper: 220.270 mg / kg and zinc: 99.199 mg / kg) and intestine (especially copper: 650.1 mg / kg and zinc: 605,014 mg / kg) had the highest levels of metals. It was heavy in duck fish (P<0.05). The study showed that there was no significant difference between males and females in most cases (P>0.05). Also, middle-aged fish had higher amounts of heavy metals (P<0.05). However, this was not accurate and in many cases the same age did not have a significant effect (P>0.05). In addition, high amounts of heavy metal were observed in fish parasites (P<0.05). Parasites appear to act as absorbers of heavy metals or transport them from the outside environment to the fish body. In terms of heavy metals, the amount of lead (average of total organs: 0.005 mg / kg) and cadmium (average of total organs: 0.0105 mg / kg) was lower than the other two heavy metals. Copper, lead, and cadmium levels were in most cases below the WHO standards. Since the amount of heavy metals in the muscle and even the gills of duckfish (in terms of food) is much less than the allowable limit, it can be said that there is no problem in terms of human consumption and to some extent the presence of these elements in The fish ignored. But oral consumption of the liver and intestines has the highest risk among the organs. In addition, the oral consumption of two different species of duck fish does not differ in the rate of absorption of heavy metals and its effect on humans.

The bony fishes of the Caspian Sea are the species whose reserves are decreasing due to Pollution, habitat destruction, exploitation and illegal fishing. Regarding the extent of illegal fishing in Golestan province and lack of sufficient studies in this regard, this study examines the changes in illegal fishing and identifies the factors involved in its occurrence. Using descriptive-analytical method, designing a questionnaire and questionnaire in person, the factors affecting the incidence of illegal fishing in the southern part of the Caspian Sea, Golestan province, were identified and ranked in two regions of Turkmen and Gomishan. Required information was collected by completing 50 questionnaires and questions related to social, economic and hunting causes during a one-year period (1395) was answered. The results showed a significant difference in illegal fishing between Bandar-Torkman and Gomishan (p ˂0.05, t- test= 3/3). Also, there was a significant difference between the winter and the rest of the seasons in the illegal fishing survey (p ˂0.05, ANOVA= 2/15). Analysis of illegal catch data by using linear regression model showed that there was a significant correlation between the probability of illegal catching of all trapped bones (in kilograms) and independent variables, including information from fish, establishment of trapping in sea, total number of traps, The main motive for hunting and the distance of the sea. This study showed that the rate of catches and reserves of bony species in the Caspian Sea has decreased, which has been accompanied by an increase in illegal fishing activities.

This study aimed to investigate the effects of different temperatures (20, 27 and 33 °C) and two feeding rates (2.5 % biomass per day and satiation) on growth performance, body composition, hematology and blood biochemistry of Asian sea bass (Lates calcarifer). For this purpose, 8 fish with an average initial weight of 99.55 ± 0.24 g were randomly transported to 200 liters tanks (6 treatments with three replicates) and fish feeding was done using a commercial feed for 6 weeks. At the end of the experiment, the growth performance, blood indices and chemical composition of fish carcasses were measured. The results of this study showed that the feeding rate of biomass (2.5%) and satitation had no significant effects on growth performance and nutrition of this fish (P<0.05). However, different levels of temperature showed a significant effect on these indices (P <0.05). The average final weight of fish grown at 33 °C and fed at the biomass level was higher than other treatments, although this difference was not significantly different from that of the stored group at 27 °C. Among the hematology parameters, the number of red blood cells showed significant changes among treatments (P<0.05). Plasma biochemical parameters such as triglyceride, glucose and cholesterol level were significantly affected by water temperature and feeding rates (P <0.05). The activity of liver enzymes in plasma was not significantly different in different treatments (P <0.05). The protein and lipid content of fish carcasses increased with increasing temperature so that the group stored at 33 °C had the highest protein and lipid content (P <0.05). In general, the results of this study showed that temperatures above 27 °C are more optimal for this species and the feed rates of biomass and satiation have no significant effect on the growth and health performance of this fish in this temperature range.

The aim of this study was to determine the effect of anthocyanin from roselle (Hibiscus sabdariffa) supplemented diets on growth, survival and body composition of rainbow trout (Oncorhynchus mykiss) for 60 days. Fish were fed 0 % (control), 0.5 %, 1 %  and 2 % anthocyanin extract in complete random design.  Fifteen fish with the same initial weight (14 ± 0. 1 g) were selected and randomly distributed into experimental treatments in triplicates and were fed 4 % biomass. Growth performance, feed efficiency, survival and body composition were assed at the end of the rearing period. The result showed that there were no significant difference between the control and anthocyanin treatments in final weight, weight gain (%), specific growth rate (SGR % day-1), protein efficiency ratio (PER), feed conversion ratio (FCR)  and feed intake (% day-1), although, growth performance and feed efficiency were  higher in anthocyanin 0.5% compared to the other treatments. Morever, There was no significant difference in survival rate between the control and anthocyanin treatments.  No significant differences was observed in nutritional carcass between the control and anthocyanin supplement. No significant differences was observed in AST, ALP and LDH between anthocyanin treatments and control group, although ALT significantly increased in 1% anthocyanin extract.The present study demonstrates that anthocyanins from roselle has no effect on growth performance, feed efficiency and body composition of rainbow trout.