JOURNAL OF AQUATIC ANIMALS & FISHERIES
Year:2015 | Volume:5 | Issue:20|Papers Count:8

Beause of the high perishability of fish, keeping the quality of Fresh fish is one of the most important problems in the fish- processing industry and for the consumers. Nowadays, important of keeping and presentation of fresh fish, with regard to consumer preference for fresh fish rather than frozen fish, is increasing. So, determination of fish shelf life, to find its consumption time, due to high perishability of fish, is important this study was aimed to investigate the process of chemical and microbial changes and determining the shelf-life of (Liza subviridis) muscle during storage period in the Ice (0-4c). For this purpose, (Liza subviridis) muscle were kept in Ice for 22 days and changes in some quality Indexes of including microbial parameters(the psychrotrophic and meso-phile bacteria) and chemical parameters (TVB-N) total volatile Basic nitrogem and Ph were measured by Kjeldahl method at (0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22) days. The results showed that the quantily of chemical indices increased during storage period, and the (TVB-N) in (Liza subviridis) at day8, was 18.6±0.30 mg in 100 g, and pH amount was, 6.31±0.01. with regard to the standard quantity of (TVB-N), the samples were out of the specified standard on 14 day. The volatile nitrogenous Bases after 8 day, stored wasnot significant difference (p>0.05) But it certainly can not say it was more corrupt. As compared with mesopilic bacteria, the psychrotrophic bacteria counts were higher. The microbial parameters decreased significantly in sanples at the begginningof the period, followed by a slower rate of increase than the chemical parameters showed a slower rate of decrease. Considering of correlation between chemical and microbial indices with total acceptability showed that the most precise indices for shelf-life-determination of (Liza subviridis) in TVC (about 4 log cfu/g) indicator and (TVB-N) (about 20mg in100 g fillet).

The following research was conducted to study the concentration of Ni and Cd in skeletons and sediments of dominant hard coral family and Poritidae in Zeyton Park, Naz Islands and Shib-deraz stations, South of Qeshm Island- Persian Gulf. The analysis of these heavy metals in digested samples of skeletons and sediments was done applying Graphite furnace Atomic Absorbtion Spectophotometry SHIMADZU, AA 670 for measuring the levels of Cd and Flame Atomic Absorbtion Spectophotometry SHIMADZU, AA 670 for measuring the levels of Ni. The concentration of Ni in skeleton of coral family Poritidae in Shib-deraz station 29.95, in Naz Islands 27.94 in Zeyton Park 26.16 and the concentration of Ni in sediments of coral in Zeyton Park station 27.91 in Naz Islands station 25.70 and in Shib-deraz station 25.50.The results indicated that there are significant statistical differences toward concentration of Ni in skeleton of coral family Poritidae among Zeyton Park, Naz Islands Shib-deraz stations (P<0.001). But Cd concentration is not significant (P=..992) In addition, considering the concentration of Ni and Cd in sediments of coral familie Poritidae there are significant differences (P<0.05 and P<0.001 respectively). Long term pollution monitoring by heavy metals is of great importance in managing coastal areas. So, concerning the immense importance of coral ecosystem in southern Qeshm Islands and the result of this research, corals can be suggested as a pollution biomonitor.

Rainbow trout (Oncorhynchus mykiss) is the most important species of rearing cold water fish in Iran. In the propagation process of rainbow trout, different factors involved in quality and quantity of female broods and their eggs and also quality and quantity of male broods and their milts. For these reasons at propagation season in 2008, is studied the effect of different age on reproductive indexes in rainbow trout broods until absorption of yolk sack stage. For this study 3 groups of male and female broods (3, 4 and 5 years old) are selected at random and after anesthetize, their age are determined and are assessed their total length, before and after stripping weight, egg diagonal, total weight of female eggs and sperm quality individually. Then broods are crossed together. The results in 9 treatments showed that in the studied treatments were statistics significant difference in mean of fertilization percentage, survival percentage to eyeing stage and hatching percentage (p<0.05 ) and the produced eggs from crossing of 5 years old females with 4 years old male have maximum rate in fertilized eggs(98%), hatching(96%), survival rate until absorption of yolk sack stage (94.5%) and number of larva with active feeding(3070). Concerning result of present study and previous studies, the age of broods, affect on fertilization stages. Therefore using of 5 years old females with 4 years old male, improve these stages.

Barbs are freshwater fish native to Southeast Asia. They are popular in aquarium fish trade due to large scales, bright color, schooling behavior, and ease of maintenance and breeding. Fairy shrimps are freshwater Anostracans which have a great importance to provide live food for cultured sturgeon, trout and ornamental fish due to high biomass, reproduction, growth rate, nutritional value and adaptation to freshwater. In this study that carried out at Azar Mahi ornamental fish farm, Tiger barb (Capoeta tetrazona) prawn ornamental fish after adaptation in two treatments were fed with cow heart and spinach- and fairy shrimp (Phallocryptus spinosa) in three replicates for 2 month. Also, all fish were fed one meal of granulated concentrate daily. The rearing and propagation condition and physic- chemical factors of water were provided at controlled condition for each group as the same. The results showed that prawns feeding with fairy shrimp had a significant higher mean fecundity (288.2±8.3) and hatching percentage (72.1±0.9) compared to 199.0±7.0 and 64.5±0.5 for manual diets (p<0.05). Also, in group fed with fairy shrimp the duration of spawning time were reduced from 11± 0.12 to 8±0.7 days and their colors were significantly enhanced. The results revealed the significant increase in fecundity and hatching percentage of Tiger barb prawns fed wuth fairy shrimp Phallocryptus spinosa.

Effects of Gillard media and 4 salinities (15, 20, 25 akd 30ppt) on growth parameter of chlorella vulgaris were surveyed using a completely randomized design. Expriments lasted 12 days. All treatments had three replication. Acording to the results the highest density of chlorella vulgaris with 125.30×106 cells/ml±0.41×106 cells/ml was observed in the treatment with salinity of 20ppt which was significantly different from the others (P<0.05). the minimum density of chlorella vulgaris with 101.62×106 cells/ml ±1.54×106 cells/ml was observed in salinity of 30 ppt. The maximum specific growth rate of 1.92±0.08 was observed in salinity of 20ppt on day2 and the minimum growth rate of 0.08±0.02 was observed in salinity of 15ppt during days 6-8. Acording to the results, Gilard medium under salinity of 20 of ppt is suitable for cultivating of chlorella vulgaris in laboratory.

The reproductive cycle the Bigeye scad (Selar crumenophthalmus) were studied from a total of 340 specimens of Bigeye scad collected in Hormuzgan waters between September 2011 and August 2012. Weight-length relationships for Bigeye scad was W = 0.032L 2.8352 Lm50 for Bigeye scad was 19 cm. Studies show that due to the length and weight of the fish is an isometric growth. Sex ratio (femail: male) for Bigeye scad 1.05:1. Maximum absolute and relative fecundity for Bigeye scad were 102841 and 581.02 respectively. Spawning seasons Bigeye scad obtained between Feb and jun. It is best to catch this species in spawning season to be prevented

The aim of this study was estimate the diversity, Richness, dominance and Evenness indices of phytoplankton community of fish ponds water in Dighche zone at east of Golestan Province. Sampling were done during one culture period from June to November 2011. The results show that there are no significant differences between different ecological indices in 3 ponds and different seasons (P>0.05). In the present study diversity, Richness, dominance and Evenness indices for phytoplankton ranged from 1.06-1.17, 0.79-0.83, 0.36-0.42 and 0.63-0.66. The highest value of diversity, Richness, dominance and Evenness indices belongs to pond 3, 2, 1 and 2 but lowest value observed at pond 1, 1, 2 and 1. Diversity index at fall and spring season had highest and lowest value. Richness index at summer and spring season had highest and lowest value. Dominance index value at spring and same in summer-fall seasons had highest and lowest value. Evenness index at spring and summer seasons had highest and lowest value. The correlation analysis between ponds water physico-chemical parameters and different ecological indices show that diversity and dominance index had high and significant correlation with P-PO4 parameter with -0.868 and 0.864 respectively. But these relatives don't observe between other parameters. The results show that different ecological indices of phytoplankton community at fish ponds affected by Soil, water physico-chemical parameters and management of a fish ponds ecosystem.

It is known that the responses to the same anaesthetic can vary considerably among different fish species. In this investigation, the efficacy of two anaesthetic agents clove powder and 2-phenoxyethanol was compared in Gropper, Epinephelus coioides. Induction and recovery times for E. coioides anaesthetised with anaesthetic agents were dose-dependent (P<0.05). The onset of individual phases of anaesthesia and recovery times depended significantly on the concentration of the anaesthetic used (P<0.05). An inverse exponential relationship was observed between concentrations of anaesthetic and induction time, whereas exponential relationships were observed between concentration and recovery times for all anaesthetic agents evaluated. The lowest effective concentrations based on the efficacy criteria of complete anaesthetic induction within 180s and recovery within 300s were determined to be 100 mgL-1 (induction 3.25±0.09 min and recovery time 3.49±0.07min) for clove powder and 200ml L-1 (induction 5.40±0.18min and recovery time 9.45±0.26min) for 2-phenoxyethanol. Clove powder was proven to be more effective and the latter appears to meet many of the criteria of an ideal fish anaesthetic.