NEW TECHNOLOGIES IN AQUACULTURE DEVELOPMENT (JOURNAL OF FISHERIES)
Year:2015 | Volume:9 | Issue:2 |Papers Count:14

Formalin is a disinfectant which is widely used to control fungal diseases in fish eggs, but its acute toxicity to the surgeon fingerlings has less been studied. OECD standard method was used to determine the acute toxicity of formalin to Persian sturgeon and stellate fingerlings in this study. After primary experiments, 8 concentrations with a control and 3 replicates apiece were established for each species. Mortalities were recorded every 24 hours and at the end of 96 hours, the values of LC10, LC50 and LC90 were calculated using Probit analysis. The results showed that LC10, LC50 and LC90 values of formalin during 96 hours for Persian sturgeon fingerlings were 4. 81, 24. 58 and 125. 57 mg/l and for stellate fingerlings were 11. 48, 20. 32 and 35. 99 mg/l, respectively. Also, MAC value, LOEC and NOEC were calculated 2. 46, 4. 81 and 2. 46 mg/l for Persian sturgeon and 2. 03, 11. 48 and 2. 03 mg/l for Stellate. The sensitivity factor showed that stellate fingerlings are 1. 2 times more sensitive to formalin compared with Persian sturgeon fingerlings.

The effectiveness of different feeding regimes for black lip pearl oyster spat (Pinctada margaritifera) based on a concentrated diet of microalgae Isochrysis galbana and Chaetoceros muelleri (singly or mixed) cultured with f/2 medium were evaluated for 30 days under laboratory conditions. Five distinct food cases (3 replications), use for testing the impact of microalgae as a concentrated form on growth and survival of pearl oyster spat. The results of present study showed that pearl oyster spat fed on mixed microalgae had relatively greater growth rate and equal survival rate compared to those fed exclusively on C. muelleri or I. galbana either when microalgae were used a concentrate diet and in particular with mixed algae when microalga I. galbana was used as a main part of diets (70% I. galbana + 30% C. muelleri). The overall growth performance clearly showed that P. margaritifera spat were successfully reared using microalgae diets tested and the pearl oyster spat fed on mixed microalgae (I. galbana + C. muelleri) showed better growth and survival rate than those that were fed on single microalgal diet.

This study was carried out to examine reproduction characteristics of Kura Barbel, Barbus lacerta from August 2010 to July 2011, in the Tajan River (Northern Iran) using electro-shocker. Totally, 234 specimens were caught. The variables of total length, fork length, standard length, body weight, age, gender, gonad’ s weight, egg’ s diameter and liver’ s weight were measured and recorded. To determine the fish’ s age, their scale was used. The total length and weight of males and females were104. 23± 1. 86 (SD) mm and 13. 7± 1. 25 g and 122. 18± 1. 41 (SD) mm and 25. 82± 1. 62g, respectively. Age readings showed that age composed of four age groups of (0+, 1+, 2+ and 3+). The gender ratio of female to male was 1. 8 to 1. The egg’ s diameter was ranged from 0. 08 until 1. 08 mm. The mean of ova diameters was 0. 54± 0. 04 mm (SD). Absolute fecundity ranged from 206 to 8689 and mean absolute fecundity was 3876. The mean GSI for males and females was 2. 34 (SD) and 2. 48 (SD) respectively. Mean condition factor (CF) was estimated 1. 12± 0. 12 (SD) for the males and 1. 16± 0. 15 (SD) for the females. The mean of HIS (hepatic index) was calculated from males and females, 1. 16± 0. 11 (SD) and 1. 12± 0. 12 (SD), respectively.

In this study, the effect of Aleo vera extract on some hematological indices of Barbus grypus were investigated. For these purpose three concentrations of Aloe vera extract, 0. 1, 0. 2 and 0. 5% (in 3 triplicates) were mixed with the food and the fish were fed with this diet for 60 days. Control group was fed with the control diet without Aloe vera extract. Blood parameters include number of white cell (WBC), red blood cells (RBC), hematocrit (PCV), hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin content (MCH) and mean of corpuscular hemoglobin concentration (MCHC) were measured. Results showed index of RBC count (RBC×106), hematocrit and hemoglobin in treatments that fed with Aloe vera extract different significantly compared to control group (P<0. 05). MCHC index in 0. 2 and 0. 5% treatments compared to control was different significantly (P<0. 05). WBC and neutrophils in that group that fed with 0. 5% Aloe vera extract were different significantly compared to control group (P<0. 05). Altogether we can say that the better doses of Aloe vera in diet for growth excitement and blood parameters are 0. 2 and 0. 5%.

This study was carried out in order to determination dominant phytoplankton species in Iranian costal waters of the southern Caspian Sea (coastal of Mazandaran) in summer and winter, 2010. The sampling was done at surface layer of 5, 10, 20, 50 and 100 m depths at 4 transects including Tonekabon, Noshahr, Babolsar and Amirabad. The results of this study showed the Cyanophyta and Bacillariophyta were dominant phyla in term of abundance in summer and winter, respectively. However, Bacillariophyta contained the highest number of species in both seasons (summer and winter). Oscillatoria sp. and Pseudonitzschia seriata (harmful and toxin producer species) had the highest abundance and frequency in summer and winter, respectively which are changed in compare to pervious studies. It seems that Mnemiopsis leidyi invasion, anthropogenic activities, discharge of organic matters and nutrients through riverine runoff have been effective factors in phytoplankton community in term of abundance and species composition.

Sampling was done from skin and gills of 420 ornamental fish, from 7 species including: gouramis (Osphronemus gouramy), guppy (Poecilia reticulate, Poecilia latipinna), Brachydanio rerio, Barbus hexazona, Xiphophorus maculatus and Xiphophorus hellerii to survey the status of their fungal infection in reproduction and breeding centers in Golestan province. Samples were cultured on Sabaroud Dextrose agar (SDA) containing chloramphenicol. Then culture mediums were incubated at 23-26 ° C for 10-14 days. Fungal colonies grown were evaluated both macroscopic and microscopic methods. In this study, four types of fungi were isolated based on morphological characteristics that included: Aspergillus flavus Yeast, Mucor spp and Alternaria sp. The highest and lowest fungi infection that observed in the skin of the fish was Yeast, Alternaria sp. (10%) and Mucor spp (4%), respectively. Also, the highest and lowest fungi infection that observed in the gill of the fish was Yeast, Alternaria sp. (5%) and Mucor spp (4%), respectively. Most of the fungal infection in the skin was observed in X. hellerii, B. hexazona and O. gouramy (10%), also, minimum fungal infection in the skin was observed in Brachydanio rerio and Xiphophorus maculates (4%). Most of the fungal infection in the gill was observed in P. latipinna, X. hellerii and O. gouramy (5%) and minimum fungal infection in the gill was observed in P. reticulata and B. hexazona that no fungi was observed.

Effect of dietary prebiotics mixture (A-max) and mannan oligosaccharide (MOS), on growth performance, survival and body composition in Grass carp juvenile (Ctenopharyngodon idella) were investigated for 56 days. Practical diets were supplemented with 0, 0. 5, 1. 5, 2. 5 and 3. 5 g/kg A-max and MOS in a totally randomized design trial in triplicate groups. The experiment carried out in 36 fiberglass tanks with filled with 1400 lit water. 50 Grass carp juveniles with initial average weight 12. 54 ± 0. 42g were stocked and fed up to satisfy. The results showed that usage of dietary A-max lead to significant differences in body weight increase, percentage of body weight increase, length increase, specific growth rate, feed conversion ratio, feed intake and protein efficiency ratio between treatments and control (P<0. 05). The best position was observed in the treatment which fed 1. 5 g/kg A-max. On the other hand the treatments which fed A-max had no significant differences in survival rate with the control (P>0. 05), even if the treatment which fed 1. 5 g/kg prebiotic A-max showed significantly better position in body composition in comparison with the control and had significantly the most protein and less lipid amount (P<0. 05). In this study, the treatments which fed with MOS had no significant differences with control in any of growth, nutrition, survival and body composition factors (P>0. 05). The experiment indicated that 1. 5 g/kg dietary prebiotic A-max has benefit effects on juvenile grass carps.

Phenotypic plasticity of body shape in five populations of the Southern kingfish (Alburnus mossulensis) was studied using geometric morphometric technique. Totally, 200 fish specimens were collected from five rivers of the Tigris basin including the Kashkan, Sepidbarg, Karun, Gamasiab and Khersan Rivers using electrofishing. The left side of collected specimens was photographed using a digital camera and 15 homologous landmark points were selected and digitized on 2D pictures using tpsDig2 software. Landmark data after GPA, analyzed using PCA, CVA and Cluster analysis and the patterns of population’ s body shape were illustrated in relation to consensus configuration of all specimens. Results revealed significant differences between all populations based on CVA. Based on cluster analysis, the populations according to their body shape were divided into three clusters including (1) Kashkan, Gamasiab and Sepidbarg Rivers, (2) Khersan River and (3) Karun River. Based on ecological similarity between rivers Sepidbarg, Kashkan and Gamasiab and their differences with rivers Karun and Khersan it can be inferred that these differences are due to their ecological conditions. Therefore, our finding can confirm phenotypic plasticity of body shape among the studied populations affected by environmental conditions.

The present paper aimed at evaluating nutritional value and fatty acid profile of muscle textures of Caspian Sea wild carp and farmed wild carp. No significant differences were found between chemical composition indices (total lipid, crude protein, moisture and ash contents) (P>0. 05). Following determination of fatty acid profiles in the Caspian Sea wild carp and farmed wild carp, fatty acid compositions in two groups of fish were found to be significantly different in terms of various fatty acid groups and ratios. In both fish, Palmitic acid (C16: 0) and Oleic acid (C18: 1 ω-9 cis) were found to be the most abundant saturated and monounsaturated fatty acids, respectively. Saturated fatty acid (SFA), monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) rates were estimated to be 26. 71%, 52. 57% and 17. 68% in farmed wild carp and 22. 78%, 40. 53% and 25. 06% in Caspian Sea wild carp, respectively. Oleic acid was significantly higher in farmed wild carp than the Caspian Sea one (P≤ 0. 05). Linoleic acid (C18: 2 ω-6) and decosahexaenoic acid (DHA, C22: 6 ω-3) were the most abundant PUFA in farmed wild carp and Caspian Sea wild carps, respectively. ω-3 fatty acids were measured to be 15. 79 and 6. 16 gr/100 gr lipid in wild and farmed carps, respectively. ω-3 fatty acids content in Caspian sea wild carp was significantly higher than that of farmed wild carp (P≤ 0. 05). ω-3/ω-6 ratio 1. 69 and 0. 76 in Caspian sea wild carps and farmed carps, respectively, that in both group exceeded the eligible rates proposed by nutritionists. PUFA/SFA ratios were 1. 10 and 0. 66 in Caspian sea wild carp and framed one, respectively; the rates exceeded the eligible rate (0. 45) recommended by HMSO. Considering exceeding PUFA/SFA and ω-3/ω-6 ratios in both Caspian Sea wild carp and farmed wild carps, both fish were considered invaluable fisheries and nutritional resources. It is noteworthy that Caspian Sea wild carp is more nutritious than farmed counterparts thank to its higher rates of PUFA, ω-3, EPA+DHA, ω-3/ω-6 and PUFA/SFA.

This study, at the time of releasing kutum (Rutilus frisii kutum) fingerlings in two Tajan River and Surkh Rud leading to the Caspian Sea for protect survival and investigated water quality was carried out with aim survival suitable and the health releazed fishes. Physico-chemical parameters of water and organochlorines pesticides were studied and compared in the range of two river estuaries from May to September. In each of river were taken three stations respectively in estuaries, location of the release kutum and upstream the water were sampled. The results showed that the electrical conductivity, total dissolved salts, salinity, ammonium, calcium, magnesium and total hardness as CaCO3 in the water Surkh Rud and Tajan River the release of kutum fingerlings is statistically significant (P<0. 05). Mean values of factors: water and air temperature, pH, dissolved oxygen water, biological oxygen, phosphate, nitrite, nitrate is not statistically significant (P>0. 05). The results investigation on water in period of release of kutum fingerlings in Surkh Rud and Tajan River some organochlorines pesticides were observed, including: Aldrin, DDD, -BHC, -Endosulfan, Endosulfan sulfate, Heptachlor, Lindane. Values measured in these rivers the concentration changes from 0. 10 to 0. 22 in micrograms per liter. Overall, results showed that more suitable Surkh Rud to the Tajan River water parameters were to release and life the kutum fingerlings.

This study was conducted to evaluate the effects of different levels of vitamin C on the minimum inhibitory concentration of mucus of Caspian roach, Rutilus rutilus caspicus. Six hundred and sixty fish were obtained from Sijaval aquaculture center (Torkemen Port) and after 2 weeks acclimation, were distributed in 12 tanks with 4 treatments and 3 replicate (55 fish in each tank). Vitamin C with 0, 1000, 1500 and 2000 mg/ kg diet doses were added to food for 60 days. At the end of trial mucus were diluted with distilled water that was 200, 100, 50, 25 and 12. 5 micro liter/ ml liter and they were put against gram-positive bacteria Streptococcus faecium, Micrococcus luteus and Gram-negative bacteria Serratia marcescens and Escherichia coli. The results by disc diffusion method were showed that 200 µ l/ml concentration of mucus have minimum antibacterial activity against two strains of bacteria. Dilution of mucus decreased the antibacterial activity. Inhibition zone diameter in fish fed with different levels of vitamin C significant increase compared to control group (P<0. 05). The results of this study were showed that increase of mucus immunity by means of disease decrease was obtained with vitamin C as an immune stimulant that is influence affects.