Iranian Journal of Fisheries Sciences
Volume:4 Issue: 1, Jul 2004

Although carp is still widely sold and used in its fresh form, a range of value additions may also be observed. It is essential to know the development and management of a carp farm production costs and their evolution. In Iran, warm-water fish farming is based on common, silver, grass, and bighead carps. The carp is easy to rise in hatcheries in very large numbers at little cost, and is distributed to farmers to grow out in cultivation ponds. The common carp and the three Chinese species are often reared in polyculture. Since, the 1970S carp farming has spread around the Caspian coasts, and farmed production reached a peak in 2001 with production of more than 28,500 tonnes. The characteristics of the carp farming industry in the three main fish farming provinces of Iran, Guilan, Mazandran and Khuzestan are quite different. A study of production, costs and profitability was carried out to help clarifying carp production costs and their differences with location and farm size. Over the years 1996-97, a total number of 153 farms from the three main provinces were randomly selected, classified and studied. The results of the survey showed that the various producer provinces have different cost structures. Overall, feed and fertiliser with the highest level of variation accounted for 45% of total costs (60% of variable costs). On average, benefit-cost ratio and the rate of farmer income were closely related to location. This result suggests that farmers practice more efficiently and have better conditions in Guilan, resulting in higher farm income per ha and per kg, followed by Mazandran and Khuzestan.

1- Iranian Fisheries Research Organization, P.O.Box: 14155-6116 Tehran, Iran2- Faculty of Veterinary Medicine, University Putra Malaysia 43400 UPM, Serdang, Selangor, MalaysiaAbstract: Shrimp aquaculture has a short history in I.R Iran. Farmed shrimp production grew slowly from 1992 until 2000 when a number of large farms started to produce. In 2000, the total production was about 4,500 MT and it was estimated that more than 7,000 MT would be produce by the year 2001. From August 1997 to March 1998, two thousand samples of cultured Penaeus semisulcatus postlarvae and subadults were collected from 5 hatcheries and 20 growout farms, distributed in 3 provinces along the coasts of the Persian Gulf and the Oman Sea. Based on, gross signs, histopathology, LM and TEM, Penaeus monodon baculovirus (MBV) from samples is recorded. The MBV is a rod-shaped baculovirus, DsDNA virus with the virion diameter of 300±75 nm. The target organ of virus is hepatopancreas and midgut epithelium.

A total number of 88 fishes Thai pangas were conducted for induced spawning experiments. Among them, 30 mature Pangasius sutchi were conducted for the length-weight relationship, 25 matured females for the fecundity and 33 fishes (12 males and 21 females) for induced spawning experiments. The total-standard length relationship curve shows a straight line with a strong correlation (r = 0.986 and 0.987). The length-weight relationship was best expressed in the logarithmic scale and follows the cube law. The absolute fecundity was ranged from 122000 to 241900 oocytes with an average of 181950 oocytes per female. In the single-dose injection pituitary extract (PG), the average number of eggs release was 182075 95136. The rate of fertilization was 69 to 95%. The average rate of hatching was 70.04 34.73%, which was higher in the peak-spawning season with PG treatment. In the double-dose experiment with HCG, the number of eggs released was 150,000 to 200,000 and the fertilization rate was 73.00 40.99% and the hatching rate was 58.33 32.78%. With the double dose of PG, the number of eggs released was 160000 to 260000. The fertilization rate was 76.50 42.68 % and the hatching rate was 58.75 32.83% with the double dose PG extract. In these experiments, it was established that the PG was more suitable and economical than HCG.

A study on motility of spermatozoa of the Persian sturgeon, Acipenser persicus were carried out. The time of relative cessation of sperm activity was evaluated using microscopic observation. Sperm was activated with three different swimming medium, freshwater pH 7.5, and two different buffered saline solutions, pH 7.5. Total period of the motility of A. persicus spermatozoa was shorter in freshwater than saline solutions. Significant correlation was found between period of sperm motility and dilution rate. Increasing dilution rate from 1:50 to 1:500 had negative effect on sperm motility and significantly decreased the duration of motility (P

A completely randomised design, with 3×3 factorial arrangement, was conducted to test various ratios of dietary protein to energy (P/E) for rainbow trout, reared in brackish water. Three crude protein levels (35, 40 and 45%) and three energy levels (370, 400 and 430 Kcal/100g) at each protein level were utilized. Semi-purified diet containing fish meal, casein and gelatin as the sources of protein and dextrin, starch and oil as the sources of energy were used. Each experimental diets was fed to triplicate groups of 20 fish with average weight of 81. 5g, in nine 2000 lit flow trough fiberglass tanks, each partitioned into three sectors. Average water temperature, dissolved oxygen, pH and EC were between 15±2؛C, 6. 5-8. 1 mg/L, 7. 7-8. 6 and 25400 µm/s, respectively. Fishes were fed for 84 days at a rate between 1. 6-2% of body weight per day, in three equal amount, adjusted bi- weekly. At each protein level, weight gain (WG%), average daily growth (ADG%), protein efficiency ratio (PER), apparent net protein utilization (ANPU%), specific growth rate (SGR) and condition factor (CF) increased, but feed conversion ratio (FCR) decreased with increasing energy level from 370 to 430 Kcal/100g. The highest growth performance was obtained by fishes fed by 35% protein, 430 Kcal/100g energy diet with P/E ratio of 81. 4 mg protein/Kcal energy. Carcass fat and moisture were affected by dietary protein and energy levels, whereas, carcass protein and ash levels were similar between dietary treatments.

During 12 months of sampling, from 17 stations, 327 specimens of Soboor fish Tenualosa ilisha, including 120 females, 113 males and 86 immature were caught. Total length (TL) of the fishes was 120-500mm. Maximum diameter of soboor ova 0.795mm and the ova with diameter more than 0.7 mm released at one spawning round. Temporal and spatial distribution of ova diameter corresponding to GSI changes showed that ova with diameters between 0.64 to 0.795 mm released spontaneously in many rounds along fish migration route during its spawning season. The results indicate that the spawning of soboor begins upon its entring to Bahmanshir and Arvand Rivers on April and continued up to Shushtar and Dezful cities on September where their migration route and season are ended.

This study was carried out in a completely randomized design 3×3×4 factorial arrangement in three periods of rearing in spring 1997. Density of 300 larvae was assigned for each oval tank with 0.1m2 surface area, 30cm deep, a volume of 20lit and 0.25 lit/min of water flow per minute at Shahid Rajaie fish breeding and culture center in Sari, north of Iran. The fries were divided into three groups according to their feeding regimes and fed with each of Artemia or D. magna speratley, and mixture of the two (50% Artemia% Daphnia) in ratioes of 80, 100 and 120% of their body weights in the first period and 30,50,70% of their body weights in the second and third period of rearing. Each period lasted 72 hours. The result indicated, significant differences (p