فصلنامه آبزیان و شیلات
پیش شماره 1 (بهار 1389)

In this study, handling conditions and harvesting process that could Effect on quality loses of cultured shrimps during the handling of shrimps to the shrimp processing factories, have been studied. Research inspection and assessments on culturing sites during harvesting and also unloading times in shrimp processing factories, have performed in Bandar Abbas. The results have taken from recorded times and temperature during preparing and handling the cultured shrimps after harvesting prosses.The measured indices were including: organeoleptical indices (The percentage of red heads, soft head and broken head disorders), the shrimp body temperature during handling to the factory, TVN (total volatile nitrogen), pH, the rate of metabisulfit absorption in shrimp muscle total count of micro organisms, total count of coli forms, E.coli and Vibrio parahemolyticus. In order to eliminate of some spare time and reduction the duration of preparing process and the handling and leaving shrimps, have been lived in cold water.The physical damages and finaly quality preservation of shrimp during transportation to the factory, a procedure depend on exploitation of CSW system accompanish with met.bi.sulfit in suitable concentration were recommend and compaired with current procedures (like handling).Total information and results indicated that, due to discorrect managements in shrimp handling in Hormozgan Province and other misapplications and unconventional stand stills, the times and temperature are not desirable. So this is necessary that these procedures would be reconsider and introduce the correct procedures. The problems were limited in recommended procedure stages and process and so the fals and human failures would be reduce. So with the CSW procedure, the shrimps could be preserved over 14 hours without organeoleptical damages.

One of the most effective factors in artemia cyst production on the semi intensive fertilized ponds is the number of reproductive females and also the density of Artemia biomass on the basis of adults weight per liter of ponds water. In this study، the effect of reproductive female''s abundance (Females/ lit-1) on cyst yields were assessed daily with ANOVA and Correlation Analytical Method. The results indicated that despite of few number of reproductive females (5 Ind/lit) and low Artemia density (0. 1 – 0. 15 g/ lit) on the culture ponds، the cysts yields at first two months of culture period (160 Kg. dw/ha) were more than the yields that harvested at three months later (47Kg. dw/ha); despite of the higher reproductive female''s abundance (more than 20 ind/lit) and a higher Artemia density (0. 2 – 0. 3g/ lit) during the last three months of cultur period، the cysts yields was declined. (Sig=0. 000).

This study was done to evaluate the effects of probiotic yeast on the growth، survival and stress resistance in Heros severus (severum) using three blends of diets containing Saccharomyces cerevisiae yeast. This experiment was done in a completely random design in four treatments. The blends of yeast such as C،T1،T2 and T3 were used in three concentration of 0. 5×1012، 1×1012 and 2×1012 cells per kg of diets. The control treatment was fed without yeast. The larvae were feed 3 times per day، every 4 hours. There were significant difference in growth factors، final weight، specific growth rate (%)، food convertion efficiency and survival rate in experimental treatments in comparison with controled treatment showed significant difference (p<0. 05). In the challenge test with ammonia stress of 3mgl-1، the severum larves which were fed on diets containing Saccharomyces cerevisiae in comparison with control group had higher survival rate (p<0. 01). The experiment indicated that the ability of yeast to influence the increase of the growth performance is relatively high.

Scombermorus commerson is one of the most important large pelagic fish species in Hormozgan Province. Nominal catch of S. commerson in 2007 was 5912 tonnes or 13% of total catch of large pelagic fishes. There was need to identify fishing pattern، maximum constant yield and recruitment pattern in order to exploitation of sustainable from stocks of S. commerson. So length and weight data were collected randomly from 3 major commercial fish-landing sites; Bandar Lengeh، Bandar Abbas and Bandar Jask in Hormozgan Province، 12 months from the beginning of April 2007. Growth parameters K and L∞ estimated 0. 66 (1/year) and 150. 24 cm respectively، so natural mortality calculated 0. 67 (1/year) and therefore maximum constant yield computed 1490 tonnes. Length-weight power relationship، W= aFLb، was W= 1. 86E-02FL2. 87 that showed S. commerson have isometric growth. Fishing pattern indicated that almost 50% of catch were under the size at first maturity. Maximum of recruitment pattern was in Mehr (October) with average fork length of 40 cm. For optimum exploitation from S. commerson stocks، two approaches are: Fishing forbidden in maximum recruitment time and gear (drift gillnet) modification.

Identification and classification of zooplanktons and determine their frequency in Iranian waters of Oman Sea before and after the Monsoon in the seasonally has been done from Hormoz strait to Pasabandar in Chabahar in the year 1386. During which 10 stations determined and collecting zooplankton with55 M closing net from the depth to the level of a vertical has been done in addition to the physical and chemical parameters such as temperature، salinity،solution oxigen and chlorophyl and pH with use of the CTD Module. In this study 62 genus of 11animal branches identified. Among the identified groups copepoda 25%، Tintinnida with 22%، Urochordata with5%، Mollusca with 2% were dominant groups. copepoda as the most important sea zooplankton in the study in 4order were identified as Cyclopoida compared to other order with one family and2 genus were the most dominant. 22% of total copepoda before and after the monsoon is allocated to Oithona genus. Distribution and accumulation of zooplankton in Oman Sea، effected by the southwest Indian Ocean monsoon wind. As far as to the result showed that the frequency of them before monsoon is the least amount of (17%) and after the monsoon the greatest amount of (83%).

The aim of this study was comparison of some postharvest handling methods، consisting of gutting، bleeding and transportation with ice and without it، in order to find the best way of handling in the studied fishes. In this study، 72 fish from three different species of Otholites ruber، Katasuwonus pelamis and Scomberomorus commerson and 24 fish from each species were selected randomly. Then each species was divided into 8 groups consisting of 3 bleeded fish، 3 gutted fish، 3 both bleeded and gutted fish and 3 unprocessed fish. These groups were transported with ice and other 12 fish with the same processing were transported without ice. Total bacterial count and coliform count were carried out on 8 groups in triplicate. The results showed that alone gutting or bleeding has no significant effect in some instances but using both methods in two different temperature of transportation have important role in decreasing total bacterial and coliform count in the studied fish species. Therefore، the best postharvest handling way in these species for achieving better final quality and increasing of storage time is a mixture of gutting، bleeding and transportation with ice.

Phytoplankton are at the base of the entire aquatic food chain. Their main applications are related to nutrition in aquaculture but they can absorbation nutrient wastewater and use them for their growth. Therefore culture of phytoplankton Chlorella vulgaris with use from urban wastewater at summer 1387 in Bandar Abbas treatment plant lab was investigated that we essayed moreover reduce of production cost، nutrient absorbation efficiency and settlement effect its. Chlorella vulgaris with some density in different condition of wastewater (20، 40، 60، 80 and 100 %) for the study on growth and three initial density،) ''high density'' 2×106 cells/ ml، ''medium '' 1 × 106 cells/ml and ''low '' 5 × 105 cells/ ml(، were applied to primarily treated wastewater. The cell number increased gradually in the fourteen days and the rates of increase in 80 and 100% were more than other cultures. At the end of the 14 days study، over 80% of NO3–N، 56% NO2–N and 80% PO43–P were removed from wastewater in all cultures except the low density one. These results indicated that the efficiency of reducing wastewater nutrients by an phytoplankton system was directly related to the physiological activity and growth of the Chlorella cells which in turn were affected by the initial density. The high density culture seemed to be more beneficial as this treatment achieved satisfactory growth and nutrient removal within 10 days instead of 14.

In this study، effect of Aqualase (1، 1. 5، 2 g/kg of feed) with three repertoire was studied on 540 samples of Common carp fingerling (with weight average 12. 4g) for 2 month. Determination of weight and lenght were done every 10 days. The results growth indicators example weight again، length again، specific growth rate، feed conversion rate and protein efficiency rate showed that 1. 5 and 2 gr of Aqualase per kg of feed gave the best results on growth of fish (p<0. 05). However، condition factor didnۥt show than control group different significant (p>0. 05). Survival rate of fish in this two treatments also were better than control، but it was not significant (p>0. 05). Then fish were challenged to streptococcus for 2 weeks. The results showed 13% mortality in control sample whereas treatment samples didn’t show any mortality (p<0. 05).