نشریه بهره برداری و پرورش آبزیان
سال دوم شماره 1 (بهار 1392)

The spatial distribution of the macrobenthic community was studied along the Bushehr Province coasts of Persian Gulf in February 2009. Samples were collected with van Veen grab, from intertidal to subtidal (depths 5 m and 10 m) zones at 16 stations determined in 6 transects, including of harbors (Genaveh, Bandargah, Rostami and Asaluyeh) and creeks (Farakeh and Shif). A total of 17 groups (taxa) of macrobenthos were identified so that the most dominant assemblages belonged to Mollusca, Annelida, Crustacea and miscellaneous groups, respectively. Generally, the environmental parameters such as water depth, sediments texture and organic matter (OM) found to influence the biological indices (density and biomass) and ecological indices (diversity and richness) of macroinvertebrates. In conclusion, with increase depth and soft sediment was observed high density and decrease biomass. Also, statistical analyses showed that density and biomass varied significantly (P<0.05 and P<0.01) which could be correlated with combination of different factors such as depth, sediment characteristics, hydrodynamic conditions.

In this study a combination of light salting and different hydrocolloids as the pre-dust on the quality of trout nugget filets and amount of its oil absorption was evaluated. After the salting, in order to apply the coated, fish pieces were pre-dust with wheat flour (control- fillet without salting, pre-dust with wheat flour) and carrageenan, alginate, isolate soy protein and hydroxypropyl methyl cellulose gums, and after battered and breaded were firying in sunflower oil. The samples were analyzed for moisture, fat, ash, water holding capacity, product yield, color and microscopic evaluation of distances between the substrate (fish) and coated. Hydroxypropyl methyl cellulose treatments showed the highest moisture content (0.05˂ P), while the fat content do not showed any significant difference between treatments (0.05˃ P). The amount of ash was highest in alginate treatments and do not showed significant difference between treatments in terms of water holding capacity and product yield (0.05˃ P). the highest amount of the lightness was observed in the hydroxypropyl methyl cellulose and control treatments, and isolated soy protein showed the highest value of the redness (0.05˂ P). The results indicated that combination of light salting and different hydrocolloids as pre-dust were affected on the amount of the moisture and ash of the products and the best materials for pre-dust fish nuggets filet, are wheat flour and hydroxypropyl methyl cellulose gum.

Activity of Cooperative Companies is among important ones in the fisheries sector and the awareness of the condition and amount of economic efficiency can be effective in making decisions about investment and economic planning of this section. In this study, it was tried to investigate profitability of these activities by estimating financial and economic indicators (stable and temporary expenditures, profitability, and payback period). The data has been collected through survey research and questionnaires. Results showed that payback period was 0.42-2.55 years and mean yearly profit for each fisherman ranged from 4719870/351 to 47787736/34 Rl. Additionally, It was observe that the profitability rate of Cooperatives in Miankaleh region is higher than in Gomishan region. It seems that fishing ground in Miankaleh is more suitable than Gomishan because of its floor type. It is necessary to optimal use of water resources, that are renewable resources, economic theory and the safe management of these resources in concerning ancient history of fisheries industry as traditional methods.

This study was conducted to determine the effect of fishmeal replacement by soybean meal on carcass composition and plasma biochemical parameters of stellate sturgeon (Acipenser stellatus). Five experimental diets formulated by substitution of 0, 10, 20, 30, and 40% of fishmeal by soybean meal. At the end of experiment, blood samples were taken from three fish of each tank and plasma glucose, cholesterol, total protein, calcium, albumen, magnesium and triglyceride in different treatments were determined. Based on the results, significant differences were found in carcass protein, lipid, and moisture content in fish fed diets with different SBM levels (P<0.05), but there were not significant difference in ash contents of different treatments (P>0.05). There were not significant differences in calcium and total protein of plasma, among treatments (P>0.05). Triglyceride levels were highest in the S10 treatment and there were significant difference between S10 and other treatments, except of F treatment. There were significant differences in plasma cholesterol, among treatments (P< 0.05) and F treatment had maximum amount. Significant differences were found in plasma albumen between S10 treatment with S20 and S40 treatments (P< 0.05). Glucose in fish fed F treatment was significantly higher than other treatments and it had statistically significant difference with other treatments, except of the S10 treatment (P<0.05). There were significant differences in plasma magnesium among treatments (P<0.05) and S40 had lowest amount. The results of the present study showed that replacing fish meal with soybean meal in juvenile stellate sturgeon diets can effected on carcass composition and plasma biochemical parameters.

The main objective of the present study was assessment of stock status of sharpnose mullet by using indicators of overfishing, condition factor and relative weight in Iranian waters of the Caspian Sea during 1991-2011. Three fisheries indicators in catch were: 1. percentage of mature fish, with 100% as target; 2. percent of specimens with optimum length, with 100% as target; and 3. percentage of mega-spawners, with 0% as target. Over this period, the condition factor and relative weight had a decreasing trend. The range of length with optimum yield was between 28 and 34 cm. The mega-spawner measured as fish a size larger than 34 cm. According to these three indicators, the percentage of mature (fork length>28 cm), optimum size and mega-spawners were 8.9-72.4%, 8.8-50.4% and 0%-23.9%, and 39.5%±16.1, 30.7%±11.8 and 9.2%±7.7, respectively in average (±S.D). This length structure is a matter of concern. Therefore, for reservation and rebuilt of sharpnose mullet in the Caspian Sea, the target would be to all (100%) fish spawn at least once, using bigger mesh size in cod end (e.g. 33 mm, during whole fishing season), also, the aim would be to implement a fishing strategy that result no (0%) mega-spawners being caught, and the main catch focus on optimum length.

The objective of this study was to examine composition of fatty acids in the muscle tissue of common carp (cyprinus carpio), silver carp (Hypophthalmichthys molitrix), bighead carp (Arigtichthys nobilis) and grass carp (Ctenopharyngodon idella), with the aim to find out to what extent the fatty acid compositions is capable to distinguish these freshwater fish. Among all the samples, palmitic and oleic acids were the principal saturated and monounsaturated fatty acids. The dominant polyunsaturated fatty acids (PUFA) in bighead and grass carp were docosahexaenoic acid and in common and silver carps were linoleic and linolenic acids, respectively. The results of principle component analysis showed that among studied variables (fatty acids), C18:1, C18:2, C18:3, C20:5, C22:5, C22:6, MUFA, PUFA6, PUFA/SFA, EPA+DHA, n3/n6 and n6/n3 had the most influence on species differentiation. The composition of fatty acid in different carp species is likely to be determined by differences in the nutrition of food sources and the enzymatic activity of fatty acid biosynthesis.

In this study, the effects of electrofishing stress on hematological parameters of wild carp (Cyprinus carpio, L.) were investigated. For this purpose, 10 fishes were considered as treatment and 10 fishes as control. Treatment fish’s were impressed by electrical shock for 5 second and blood was sampled from caudal vein via streel syringes and hematological parameters were investigated. Results showed that electrofishing had significant (P<0.05) impact on leukocyte number, but no significant (P>0.05) changes showed in other parameters. Based on results, increasing the number of leukocyte is the first and quickest reaction of carp to electrofishing.

In this study, 374 specimen of mullet, belonging to Liza aurata and Liza saliens species, were collected from 4 different stations of southern coasts of the Caspian Sea including Anzali, Kiashahr, Bablsar and Bandar torkaman. Different parameters such as Length-weight relationship, Growth pattern, condition factor, Von Bertalanffy growth parameters, age and sex were investigated in the present study. ANOVA revealed no significant difference as regard to the length and weight among 4 investigated locations (P>0.05). L∞ was estimated 54.7 cm and 40.07 for Golden and Sharpnose mullets respectively. The significant differences among some factors like condition factor (K) could attributed to environmental variation in the Caspian Sea.

The purpose of this study was to study of the behavioral responses of Rutilus frisii kutum to various concentrations of stimulant taste substances. 20 fish with average weight 1.5 ± 0.5g placed in individual aquarium with a volume of 5 liters. After the fish adapted to laboratory conditions, we investigated their behavioral responses to different concentrations of taste materials (Acid citric, Calcium chloride, Sodium chloride, Sucrose), control and extract of chironomid. During the first minute of experiments Granules containing the mentioned materials were given to the fish and the behavior of fish was recorded by a camera. Taste preferences were determined according to behavioral responses of fish to granules. None of the concentrations of acid citric was deterrent. Concentration of 0.026 M was most attractive with 48.49±7.1 of consumption and attractiveness index 59.87±9. Percent of consumption and attractiveness index of Sodium chloride in all concentrations were not statistically significant compare to control treatment (P>0.05). Percent of consumption and attractiveness index of Sucrose was more than those of Sodium chloride and Calcium chloride. The number of grasps in concentration of basic (10%) Sucrose, Sodium chloride and Calcium chloride was statistically significant compare to control treatment (P<0.05). There was a positive correlation between the attractiveness index and retention times in the mouth but not for number of grasps. The results of the present study can be applicable for feeding and providing suitable and appropriate diets consistent with taste preferences for this species.

The objective of this research was to evaluate the effects of LHRAH-A2 alone and in combination with pimozide (dopamine antagonist) on percentage of ovulated females, latency period, ovulation index, work fecundity, egg weight to body weight ratio, fertilization success and Hatching rate of kuttum. 63 fish were treated and hormone treatments included: 1- LHRAH-A2 (1µg kg-1 bw), 2- pimozide (5 mg kg-1 bw), 3- combination pimozide and LHRAH-A2 (5 mg kg-1 bw + 1µg kg-1 bw), 4- carp pitatury extract (positive control), 5- saline solution 0.7% (negative control) 6- untreated group (without injection). The injection was performed intramuscularly. fish ovary in each treatment were analyzed using classical histology. The highest percentage of ovulated females (77.8 %), lowest latency period (34.2 ± 4.7), highest egg weight to body weight ratio (14.2 ± 1.3), fertilization success (95.9 ± 0.8) and hatching rate (44.2 ± 10.4) were observed in treatment 3. In ovulated fish, histological analysis revealed six stages in ovaries, while ovaries in non-ovulated ones were developed only in fourth stage. It seems that Because of ovulation can be induced successfully in kutum broodstocks with 1µg kg-1 bw LHRAH-A2+ 5 mg kg-1 bw pimozide treatment in a single injection with high percentage of ovulated females, lowest negative effect on propagation quality and its more cost-effectiveness than CPE, so Application of this combination could be beneficial for the development of artificial propagation methods in kutum brood stocks.

Compensatory growth, feed efficiency and body composition of rainbow trout larvae (mean weight 300±10 mg) were investigated for 40 days with three feeding conditions: one group control (fed every day) and the other two groups as 5+2 (fed 5 days, staved 2 days) and 2+2 (fed 2 days, starved 2 days). The trout larvae were feed on 10 percentage of their body weight. At the end of the experiment changes in growth parameters, feed performance and body composition were evaluated. These results indicate that reduced significant were found in growth parameter between the deprived and control fish during experiment (P<0.05). Body weight increased (BWI) was significantly higher in control treatment than in experiment treatments. No differences of condition factor (CF) in between two starvation treatments compensated with control. Average feed conversion ratios were between 1.32 and 2.42. The amounts of PER, LER and EER in control treatment were significantly promoted in comparison with experimental treatments (p<0.05). In the termination of the experiment, the whole body samples of fish larvae were body composition analyzed. The result indicate that short term starvation significantly decreased levels of crude protein in experiment treatments in comparison with control treatment (p<0.05). Average protein crude was between 60.99 to 72.54%. Overall, the result showed that alternative feeding due to particle compensatory growth in rainbow trout larvae.