NEW TECHNOLOGIES IN AQUACULTURE DEVELOPMENT (JOURNAL OF FISHERIES)
Year:2009 | Volume:3 | Issue:3|Papers Count:13

This study was carried out from September 2006 to August 2007 in order to estimate heavy metals accumulation Cadmium, Copper and Iron in the muscle, gills and liver tissues of Johnius belangerii collected from Deylam in Bushehr Province. Sampling was performed seasonally and the study aimed to compare heavy metal concentrations in the fish with the safe limit standards. Fish samples were collected randomly from the catch of trawl fishing. After biometry of fish they were divided into three length groups A, B and C; and tissue samples were taken from each length group and analyzed for heavy metals content using atomic absorption spectrophotometer. Heavy metal concentrations were significantly different between fish tissues, stations and seasons. The highest concentration of cadmium, copper and iron were recorded in the liver tissue and the lowest concentration was observed in the muscle tissue. The concentration of heavy metals showed a marked decrease from autumn to winter, and then increased from winter to summer. This trend was observed for all of the metals and could be related to the seasonal variations such as temperature and salinity changes. Cadmium concentration measured in fish samples was found to be above the safe limit proposed by MAFF, NHMRC and WHO while the concentrations of copper and iron were below the standard safe limits.

A completely randomized design was conducted to determine the effect of four concentrations of waterborne sodium (2, 14, 50, 100 mg L-1) on excretion of ammonia in embryonic rainbow trout in a water recirculating system. Twelve experimental units, with the capacity of holding 45 liter of water were used and 22.5 g egg introduced in each one. Different water media (treatments) was made, using analytical salts (Merck), added into double-de-ionized distilled water. Water temperature variations during incubation period were 7.5-9 oC. Ammonia in external water measured during the incubation period every week. Prior to allocating the newly fertilized eggs to trays as well as at the time of hatching, sodium ion and total nitrogen measured in whole egg. Ammonia level was significantly (P<0.05) different between treatments, so that the highest ammonia level was observed in the [Na+] 2 mg L-1. In all treatments, total nitrogen of whole egg did not significantly (P>0.05) change compared to newly fertilized egg. Variation of whole egg Na+ was significant (P<0.05) among treatments and newly fertilized egg. Whole egg sodium content in [Na+] 100 mg L-1 was higher than other treatments.The results of this study indicated that excretion of ammonia by embryos of rainbow trout to external water does not increase along with increasing waterborne sodium concentration and higher sodium uptake by egg.

This study was conducted to determine the muscle chemical composition (protein, lipid, ash and moisture) of Schizothorax zarudnyi and Schizocypris altidorsalis and their changes related to sex and season during the year (autumn 2007-summer 2008) in University of Zabol. The results indicated that the chemical composition of both fish depends on season and sex. There were differences in annual changes between S. zarudnyi and S. altidorsalis, as the highest moisture content and lowest protein and lipid content was observed in autumn for S. zarudnyi, while it happened for S. altidorsalis in spring. The lipid content was more in S. zarudnyi muscle than S. altidorsalis muscle. The mean, minimum and maximum protein content of S. zarudnyi muscle were 14.47±0.61, 12.77 and 16.50 percent in male and 14.18±0.95, 13.22 and 15.32 percent in female, respectively. The mean, minimum and maximum protein content of S. altidorsalis muscle were 14.45±0.87, 13.03 and 16.27 percent in male and 14.25±1.00, 13.05 and 16.04 percent in female, respectively. The effects of sex and season on muscle moisture content in both fish were significant (P<0.05).

In this study, 5 diets was formulated to examine the effect of replacing 0, 25, 50, 75, 100 % of canola meal to soybean meal on the growth performance of rainbow trout (Onchorhynchus mykiss).All of the experimental diets were iso-caloric and iso-nitrogenous. The experimental period was 63 days and used a total of 450 rainbow trout weighting 10gr randomly assigned to 15 tanks (30 fish per tank). Three tanks used to each diet. At the end of trial, performance was determined by weight gain, total feed intake, feed conversion ratio, protein efficiency ratio, specific growth rate and survival.There were no significant difference in any of the performance growth and feeding parameters. These studies show that canola meal has potential to replace substantial level of soybean meal in diets for rainbow trout with no significant decrease in growth or feed efficiency.

The Qezel owzan river is one of the most important rivers the Zanjan province. Main purposes of the study were: Determination of fish diversity and abundance. Studied fishes have been sampled in 5 stations from 2008 until 2009. Electroschoker, cast net and dip net were used to catch them. Results showed that10 species fish belonging to 2 families: minnows (Cyprinidae) and hillstream loaches (Balitoridae) exist in the river so that Cyprinidae with 7 genus and 9 species and maximum abundance (98.2%) is prevalent and Balitoridae had one species represent. Capoeta capoeta gracilis was prevalent in 3 seasons and in stations 3, 4, 5 too and Alburnoides bipunctatus in 1 season and in stations 1, 2. In addition, C. capoeta gracilis, A.bipunctatus, B.capito with abundance 33.6, 22.1 and 13.1 % of total number of caught fishes in the study were respectively abundant. In the study was observed the least diversity (4 species) in 3 stations and the most diversity (10 species) in downstream station (S 1).

This research has been conducted in the conservation center of shahid Bahonar-kelardasht for two month in the 1387. In this regard, used of 3 level age 2+, 3+, 4+ and 9 bloodstock in any age. In 3 groups with Striping Frequency was appointed in the any age. Bloodstock males striped to three groups at weekly (8 times in duration), 10 day (6 times in duration) and 2 weekly (4 times in duration) intervals, respectively. Results show that spermatocrit in males 2+ by 10 days and 2 weekly interval striping was highest and no significant, (44.16±0.76%) and (46.16±0.76%) respectively. Spermatocrit in the age level 3+ was significant difference, to this case; the highest of spermatocrit was produced by the 2 weekly, (46.16±0.76%). Spermatocrit was highest in different groups of males 4+ interval striping by 10 days and 2 weekly, (39±1.32%) and (40.16±1.04%) respectively, and were no significant difference in the 2 groups. Duration of sperm motility in different groups of males 2+ was no significant difference but highest in males 3+ by weekly interval striping, (26±0.5 sec). Duration of sperm motility was highest in groups of 4+ by weekly and 10 days interval striping (28±1.2 sec) and (27.16±0.28 sec) respectively. In different groups of age 2+ of eyed eggs stage was no significant difference (p>0.05). Eyed eggs stage in males 3+ by 10 days and 2 weekly interval striping was highest and no significant difference, (85±1%) and (85±1.33%) respectively, (p>0.05). The highest of eyed eggs stage in age 4+ were by 10 days and 2 weekly interval striping, (78±1%) and (80±1%) respectively. In comparison to groups, spermatocrit was highest by 2 weekly striping and lowest weekly. The highest sperm motility was by weekly striping but eyed eggs stage by 2 weekly. Final conclusion confirmed that, the best of bloodstock males age is 2+ and 3+ for fertilization. The best of Striping Frequency by 10 days and 2 weekly.

There is high potential of aquaculture with use of underground brackish water especially in central areas of Iran; in the other hand environmental factors have so important affects on gonad quality of rainbow trout. According to them and earlier gonad maturation of rainbow trout in brackish water; usage possibility of underground brackish water for broodfish rearing of Rainbow trout (Oncorhynchus mykiss) and evaluation of their gametes quality have studied. Broodfish have reared for 6 months in underground brackish water (11.5 ppt) in Bafgh area and with fresh water in Yasouj region. Results showed that there weren’t any significant difference in growth indexes of broodfish (weight, length and condition factors) and they were matured and spawned successfully in Bafgh area and gonad quality in brackish water was better than fresh water significantly. In result, broodfish rearing will be useful in underground brackish water, if suitable thermal condition be prepared.

Bream fishes (Abramis brama orientalis) are the valuable bony fishes of Caspian Sea. With respect to this point that there is not any report in application of HCG hormone in composition with Metocloparmide on bream fishes, the executive operation of this research has been assessed on May 09, 2008 and it was coincident with the commencement of reproduction season. To execute this research, 7 groups of treatment have been considered which are included: hypothesis (4 mg/kg B.W.) as control group, treatment group of HCG with three injection doses (1000, 2000 and 3000 IU/kg B.W.) lonely and in compound with Metocloparmide with the dose of (5 mg/kg B.W.). With calculating of 5 females as the repetition for every treatment, totally 35 pairs of male and female breams were considered for this research. The results of this research showed that to the operations of hormone trophy with the only usage of HCG were not successful in any of the bream female reproduction fish but a compound of HCG hormone with Metoclopramide had a favorite result, so that the highest percent of response with the amount of 80% is belonged to treatment fishes of HCG with the dose of 2000 IU/kg in compound with MET with the dose of 5 mg/kg and control group. Also, the most percentage of egg fecundation was related to the above-mentioned treatment group with 61% and control group with 69%. In the viewpoint of the percentage of hatching, the most amount were related to treatments of HCG in two doses of 3000 IU/kg and 2000 IU/kg in compound with MET with dose of 5 mg/kg for 70 and 75 percent respectively and the control group with 78 percent. Therefore, with respect to the acquired results, treatment group of HCG with the dose of 2000 IU/kg in compound with MET at dose of 5 mg/kg and the control group have the most suitable particulars as the fecundation in artificial propagation of bream reproductions. Also, on the basis of the performed analysis on 35 bream reproduction fish, these averages are obtained: Average of weight: 792.43±59.38 g, Average of the total length: 34.19±1.06 cm, Average of the round of stomach: 26.31±0.98 cm, Average of age: 4.00±0.14 year. In the statistical analysis on reproduction treatment groups of HCG in compound with MET and the control group which have given positive respond to the hormone injection operation, these measurements are determined: The degree- hour maturation of bream fishes: 308.92±14.97 degree-hours, The average of the extracted ovum weight: 87.09±8.44 g, The percent of the ovum weight to the body weight: 8.78±0.30 percent.

In this experiment, Gammaruses (Pontogammarus maeoticus) which were collected from southern coast of the Caspian sea in Anzali area firstly, were dried by 4 different drying methods in 4 isolated groups which were consisted of: hot air current, indirect sunshine, direct sunshine and hot surface and then, the average amount of total protein and lipid in dried Gammarus was measured in the laboratory.The results of the Analayz-Varians among the groups showed significant differences in the average amount of lipid (P<0.01) and protein (P<0.05). In addition, by comparing of these factors by the Duncan test, the greatest amount of protein in hot surface method (47.57%) and the least amount of protein in hot current method (45.98%) were absorved. Also, the most amount of lipid in hot surface method (6.06%) and the least amount of lipid in sunshine indirect method (3.39%) were resulted.

In a 14 days period, photo's color effects and photoperiod on growth and survival rate in Rutilus rutilus caspicus larvae have studied. The roach larvae have provided from fish reproduction and culture center of sijual. After adaptation, the larvae have stocked with primary weight 3.1 mg in som tanks (40 lit) that there were just 20 lit fresh water in, with 100/each tank. Using fluorescent lights, two photic treatment have studied that include red and white color and tow photoperiods that consisted of 12L/12D and 24L/00D in four different treatment including red photo and 24L/00D, red photo and 12L/12D, white photo and 24L/00D and white photo 12L/12D.Along analysis the temperature were in 18-20 oC. Results showed that red photo and 24L/00D have maximum rate of growth and minimum FCR and so have significant difference with other treatment, while to treatments red photo 12L/12D and white photo 12L/12D have not significant different and then they have minimum rate of growth and maximum FCR. Also, photoperiods didn't show any significant difference as larvae survival rate.In all of photic levels, the survival rate were relatively high.