نشریه بهره برداری و پرورش آبزیان
سال دوم شماره 2 (تابستان 1392)

This study was conducted on population dynamics of giant sea cat fish, Arius thalassinus in the Eastern coastal of Qeshm Island, Persian Gulf. Age of fish was estimated by second pectoral radial bone. Growth was estimated by the Von Bertalanfy growth model. The results showed that growth parameters for A. thalassinus were: Lt=90.36{1-exp [-0.17(t-0.07)]} and Lt=101.89{1-exp[-0.20(t- 0.41)]} for female with a growth performance index of ǿ=3.423. The meane lenght of A. thalassinus specimens caught in the study area 47.63±13.64 cm for males and 52.17±12.4 for females. The weight meanes for males and females were 1.34±1.10 and 1.67±1.27 respectively. The b was 2.99 and 2.20 for male and female that shows growth in A. thalassinus is allometric. Sex ratio during the study was 1:1.77 (χ2=1.75, P<0.05). The instantaneous natural mortality coefficient was 0.36 and 0.33 in female and male. According to the results of this study. A. thalassinus have low growth rate, high L∞ and common recruitment pattern the same of tropical fishes.

The hematological indices of Siberian sturgeon Acipenser baerii were studied in the different stages of sexual maturity (stages II, III and IV) in both genders. Red blood cells (RBCs), white blood cells (WBCs), haematocrit (Hct), hemoglobin (Hb), Mean Corpuscular Volume (MCV), Mean Corpuscular Haemagolobin (MCH) and Mean Corpuscular Haemagolobin Concenteration (HCHC) were measured in different seasons (from summer 2009 to spring 2010). RBC counts and Hct varied significantly (P<0.05) among different seasons in all three different stages of maturity. WBC counts showed considerable variations in stages II and III of maturity (P<0.05). MCV changed significantly (P<0.05) during different seasons in all three stages of maturity. The highest value for MCV (676.86±23.45 fl) was found in winter. MCHC had no variation during different seasons (P>0.05). Hb was lowest (4.95±0.98 gr/dl) in stage II of maturity in spring. The results of this study showed seasonal variations in haematological parameters of blood in Siberian sturgeon kept in captivity and should be considered when these parameters are utilized to evaluate fish health status. But sexuality did not effect on haematology parameters.

In the present study, the population structure of 128 specimens of Vimba persa was investigated from Talesh, Anzali, Kiashahr, Langroud and Chalus shores in Caspian Sea, accompanied with Tonekabon river using the morphometric and meristic characters. Altogether, 24 morphometric features including 20 truss distances as well as eye diameter, interorbital width, snout length and cheek length and also 10 meristic counts were measured on each individual. Our results revealed significant differences with varying degrees between the means of the samples for 18 standardized morphometric measurements and 5 meristic counts (P<0.05) that showed high significant differences between the studied vimba samples. In discriminant analysis, the average of correct assignment of individuals into their original samples for morphometric and meristic characters was 76.6% and 50.8% respectively. Plotting discriminant functions 1 and 2 for morphometric measurements revealed a high discrimination between the samples of Anzali shore compare to other areas. In this regard, the samples of Langroud shore had a close morphometric similarity to Western Mazandaran (Chalus shore and Tonekabon river) while, the samples of Western Mazandaran were tightly close to each other. For the meristic characters, the amount of discrimination was low and the samples showed a high overlap revealing the less efficiency of meristic characters in separating the populations compare to morphometric features.

In the present study, for the first time in a primitive fish species, the possibility of ascorbate biosynthesis during early development of Persian sturgeon was investigated via the evaluation of mRNA expression and GULO enzyme activity. The results showed that GULO gene is expressed in all developmental time-points of Persian sturgeon from eyed eggs (embryonic stage) to juvenile fish in both mRNA and protein levels. This suggests that: (i) Persian sturgeon can synthesize ascorbate; (ii) The ascorbate synthesis probably starts already before hatching. The mRNA expression of GULO was highest at embryonic stage (two days before hatching; P<0.05) and started to decline from hatching of larvae to the rest of developmental time-points. The GULO activity was detected in all developmental time-points of Persian sturgeon. However, Statistical analysis of the results indicated that the observed changes in the GULO activities were not significant (P>0.05). Our results suggest that some parts of vitamin C requirement must be fulfilled by endogenous formation of ascorbic acid during early larval development stages of sturgeon fish.

The purpose of this study was to evaluate the anesthetic effects of three plant extracts on common carp (Cyprinus carpio). Melissa officinalis and Valeriana officinalis extracts were prepared by the method of Maceration and Salvia officinalis extract was purchased from market. Different concentrations of those extracts were used on common carp with a mean total length of 12.48±1.85 cm and mean body weight of 27.25±7.99 g. Melissa officinalis concentrations were used 25.5, 51 and 76.5 g/l, Valeriana officinalis concentrations were used 4.15 and 6.81 g/l and Salvia officinalis concentrations were used 0.075, 0.125, 0.175 and 0.225 g/l. During the experiment, physicochemical factors including water temperature, pH, salinity and water hardness, were measured 21 oC, 6.7, 1.02 ppt and 651 mg CaCo3/lit, respectively. Statistical analysis of all data was performed using ANOVA and Duncan test was used for determining of significant differences between treatments (P<0.05). Comparing of three extracts can be concluded that the application of low concentrations of all three extracts showed significant differences (P<0.05) and at higher concentrations, the significant trend is reduced. The shortest time to complete anesthesia was 253.3±0.5 seconds in concentrations of 0.225 g/l of Salvia officinalis and for full recovery was 210±30 seconds in concentration of 76.5 g/l of Melissa officinalis. The maximum time for full anesthetic was 1170±30 seconds in concentration of 25.5 g/l of Melissa officinalis and maximum time for full recovery was 490.3±3.51 seconds in concentration of 0.075 g/l of Salvia officinalis.

A 60 days feeding experiment was carried out on kutum (Rutilus frisii kutum) with 1.21±0.02 g (Mean±SD) to invastigate the effects of different levels of High unsaturated fatty acids (HUFA) on fish growth, hematocrit and some biochemical blood parameters. Six-hundred kutum were randomly distributed between four groups. Fish were fed with diets containing different levels (1.56, 3.26, 6.89 and 6.9 % of total fatty acids) of n-3 HUFA in diet. Weight gain, feed conversion ratio, specific growth rate and survival (%) were not significantly different in treatments (P>0.05). There was no significant difference between hematocrit, plasma protein, glucose and cholesterol contents of dietary treatments (P>0.05). The results of this study showed that diets with a minimum amount of HUFA, had no effect on kutum growth and n-3 HUFA was not a limiting factor in this fish.

Although there is no much information about shrimp industrial trawler, the aim of this study was to estimate the catch composition and Catch per Unit of Area (CPUA) of Penaeid shrimps from the bottom trawls of Bushehr coastal waters. Sampling was carried out by stratified sampling producer in the three strata: <10 m, 10-20 m and 20-30 m. The catch composition included: 95.93% Green tiger shrimp (Penaeus semisulcatus), 3.17% Jinga shrimp (Metapenaeus affinis), 0.37% Peregrine shrimp (Metapenaeus stebbingi), 0.37% Kiddi shrimp (Parapenaeopsis stylifera) and 0.18% Fiddler shrimp (Metapenaeopsis stridulans) during the 44 haul. The overall CPUA index for shrimp was 98.51±153.22 g/km2 in Bushehr coastal waters. Green tiger shrimp (P. semisulcatus) with 94.5±151.9 g/km2 was the dominated species and its distribution was significantly different between the north and south fishing grounds (P<0.05). One-way ANOVA test showed a significant difference between the CPUA index of different shrimp species (P<0.05). Also, the CPUA index was computed for each species from all the strata and the Two-way ANOVA test indicated no interaction between the depths and the shrimp species (P>0.05).

Being succeed in aquaculture is mainly dependents on environmental and cultural conditions. Density, temperature and water flow are the most important factors that influence water quality and aquatic conditions. This study conducted to evaluate the effects of mentioned factors on feed consumption, food conversion ratio and growth of rainbow trout (Oncorhynchus mykiss). According to the Response Surface Methodology (RSM), at a 60 day trial, 1400 fry (mean weight 10±1.5) exposed in different water flow (0.1, 0.2 and 0.3 l.s-1), density (50, 70 and 90 individuals) and temperature (10, 15 and 20 oC) and fed by commerical diet. At the end of trial, food intake, food conversion ratio and weight gain optimized according to the objected factors. After data analysed, results revealed that food intake affected by different densities (P<0.05) but temperature and water flow did not affect significantly (P>0.05). Food conversion ratio and growth significantly affected by density and water flow (P<0.05); but Water temperature did not affect on this factors (P>0.05). According to this experimental conditions 170 fish.m-3, 0.9 l.s-1 of water flow and temperature of 15 oC, will achieve best food intake, food conversion ratio and growth.

In this study that was done at Ornamental aquaculture center in Toushan village, acute toxicity test (LC50), NOEC and LOEC of Gold fish (Carassius auratus) were detected during exposure to diazinon and deltamethrin. These toxins are one of the most important organophosphate toxin in control of insects during agricultural and urban usage. Adult goldfish were exposed to different doses of toxins for 96h in group of 21 individuals and mortality rate was recorded. After 96h, there was 100% mortality at doses of 40, 80 ppm diazinon and 0.40 ppm deltamethrin. LC50-96h were 19±0.196 and 0.17±0.02 for diazinon and deltamethrin respectively.

This study was conducted to examine the effects of different content of vitamin E and highly unsaturated fatty acid on growth and some biochemical blood parameters in Goldfish. Goldfish with initial weight 0.69±0.12 gr were fed with diets which having different levels of vitamin E and highly unsaturated fatty acid (E100+HUFA, E50+HUFA, -E+HUFA, -E-HUFA) for 10 weeks. At the end of period the Final weight, specific growth rate, feed conversion ration, condition factor, survival and blood biochemical parameters were measured. The result of this study showed that the difference between the final weight, specific growth rate, feed conversion ratio, condition factor and survival between treatments were no significant (P>0.05). Moreover, Effects of the diet were significant on Cholesterol and Glucose (P<0.05). Diet with vitamin E and HUFA has good effect on blood parameter and growth factor in gold fish.

In order to investigation of acute toxicity heavy metal copper on blood biochemichal parameters of silver carp (Hypophthalmicthys molitrix), a total of 135 fish (with mean weight 52.6 ±8.1 gr and mean length 17.2 ± 2 cm) were exposed to 0, 5 and 10 mg/L of Cu (NO)2. Results of biochemical parameters showed significant changes, but not about cholesterole. Glucose levels were increased significantly (P<0.05) in 24 than 12 hours. Total protein levels were decreased significantly (P<0.05) at treatment 5 mg/L at both times. Albumon levels were decreased significantly (P<0.05) in 12 hours. Based on results, biochemichal parameters are useful to monitoring of copper acute toxicity in Sliver Carp.