فهرست مطالب

Iranian Journal of Fisheries Sciences
Volume:7 Issue: 2, Jan 2008

  • تاریخ انتشار: 1386/11/15
  • تعداد عناوین: 9
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  • Lead contamination in fishes of the Kor River
    M. Ebrahimi M. Taherianfard, M.M. Rafiee Pages 1-44
    Lead concentration in muscle, liver, kidney, brain and gonad tissues of two cyprinid fishes, Cyprinus carpio and Copoeta spp., from three sections of the upper, middle and lower parts of the Kor River was evaluated in 2006. Totally 225 specimens were caught for this purpose (75 specimens from each zone). Tissue samples were digested in acid and their lead concentrations were assayed by ICP method. Statistical analysis of data showed significantly (P<0.05) higher concentrations of lead in the mid zone than the two other zones. No significant differences (P>0.05) were seen between sexes and species. The same pattern of contamination was also observed in water and sediment samples from three sampling zones. The maximum amount of lead measured in this study (1.85mg/kg), was, however, less than the maximum allowance in fish tissues by European Unions.
  • A.H. Esmaily, M.R. Kalbassi Pages 15-26
    Karyological characteristics of bighead goby (Neogobius kessleri) in the Caspian Sea were studied by examining 30 metaphase chromosome spreads from the kidney tissue of 10 specimens. The chromosome number of this species was found 2n=46 and the arm number as NF=46. The prepared karyotype of this species consisted of 23 pairs acro-telocentric (a-t) chromosomes. The chromosomal formula can be stated as 2n=46 (a-t). Karyological parameters showed that relative length was between 2.34-7.04 and length variation range of chromosomes was between 1.67-5.01 and total length was 71.16µm. It was found that the best chromosomal spread quality were obtained from intraperitonial injection of 40µg/g colchicine for 5 hours, hypotonization of samples in %1 sodium tri-citrate solution in 4ºC and preparation of spreads on cooled slide with flame technique.
  • D. Karimi K. Kuperan, F. Eslami Pages 27-46
    The non-compliance attitude with the fishing regulations of the Iranian fishermen in three provinces of Khuzestan, Bushehr, and Hormozgan along the Persian Gulf was investigated. By using a questionnaire and a stratified random sample method, a total of 566 fishermen were interviewed. The legitimacy variables (outcome and process) that can explain the observed noncompliance with zoning regulation for shrimp fishery were examined. A Tobit econometric technique was used to estimate the violation decision by Iranian fishermen in the study area. The model was classified into two types: the basic model and the extended model. The key results indicate that one of the factors influencing fishermen to violate the regulation is the differential in the potential income between shrimp fishing zone and other areas. The results also indicate that the moral judgment variable (MCODE) and exogenous variables of probability of detection and conviction play a key role in the violation decision of fishermen. In general, the extended model using exogenous determinant of probability of detection and conviction in the Tobit estimation technique gave better results than the enriched model using raw probabilities.
  • Gh.R. Rafiee, Ch.R. Saad Pages 47-58
    Natural zeolite was used as a bed medium for plantation of lettuce seedlings and its effects on growth and chemical composition of red tilapia and lettuce were investigated in a pisciponic system. The place of study was the Aquatic Resources Technology Laboratory, Faculty of Agriculture, at the University Putra Malaysia, in 2002. The mean individual weight and biomass of fish in the treatment with zeolite were significantly higher (P<0.05) than the control at the end of experimental period. Use of zeoilte as bed media to plant lettuce seedlings significantly (P<0.05) increased the yield of lettuce. The yield of lettuce in zeolite bed medium and control treatments were 1507±83 and 275±48g, respectively at the end of the experiment. The percentage of protein, fiber and ash in the dry weight of fish were not significantly different (P>0.05) between treatments. The percentage of ash in the dry weight of lettuce in the control was significantly (P<0.05) higher than the zeolite bed medium group. It was concluded that the use of zeolite as bed medium to plant lettuce seedlings could improve culture system performance due to its positive effects in lettuce growth.
  • H. Salehi Pages 59-72
    Iran contributes to the stock enhancement of several economically valuable fish species, including the Caspian salmon, S. trutta caspius, by producing and releasing millions of fingerlings into the sea. This work was conducted to determine the production costs of the Caspian salmon fingerlings in the years 2002 and 2003. For this purpose, a questionnaire was prepared and filled in by an expert team using data available in the Kelardasht Caspian Salmon Hatchery and other related departments. Among various expenditures, on average, cost of labor (52%) and cost of feed (16%) had the greatest share. Results showed the average cost of production and release of a single fingerling in Iran was IRRls 6,685, (US$ 0.84) over the 2002-2003. The cost sensitivity of hatcheries production of the Caspian salmon shows that labor cost is the most sensitive, and a 50% increase in the cost of this item increases the total coast by more than 25% followed by feed cost.
  • M. Sayyad Bourani, S. Abdolmalaki A.A., Khanipour H., Fazli K., Khedmati Pages 73-86

    Population structure of three kilka fishes (Clupeonella spp.), particularly anchovy kilka (C. engrauliformis), in Iranian waters of the Caspian Sea was surveyed in 2003. A total of 3230 biweekly samples were collected from commercially landed kilka at 3 stations in Mazandaran and Guilan provinces. Catch and effort statistics were obtained from the relevant organization. Results showed a great decline in the commercial kilka catch from 95000 tons in 1999 to 15497 tons in 2003. The contribution of anchovy kilka to the total kilka fishery also showed a decline from 71% in 1999 to 52.5% in 2003, while common kilka (C. cultriventris) increased from 13.7% in 1999 to 48.9% in 2003. Fork length range of anchovy kilka showed an increase from 89.2±12mm in 1999 to 100.4±4.9mm in 2003. The age composition of anchovy ranged between 1+ to 7+ years and the dominant group was 5+ years old (age group of 4+ and 5+ comprised 84.6% of population). The K value and L∞ calculated 0.598/year and 110.13 mm respectively. Natural, fishing and total mortality coefficient was estimated 0.69, 0.31 and 1 per year respectively. The results showed a sex ratio of F: M= 68.2: 31.8.

  • M. Soltani S. Khazraeenia, H. Sepehri Pages 87-102
    Levels of phenoloxidase (Po), trypsin and lysozyme activities were determined following 48 hours exposing freshwater crayfish (Pontastacus leptodactylus) weighing 59.8±3.4g to different low pH values of 6.5, 5.5, 4 and 2.5 at 20-23˚C. Significant decrease were found (P<0.01) in levels of Po and trypsin activities in crayfish haemocyte lysate supernatant (HLS) at pHs 5.5 and 4 compared to the control group (pH 8). Also, plasma lysozyme activity showed a significant increase in water with pHs of 6.5, 5.5 and 4 (P<0.01). Furthermore, measurement of calcium and magnesium concentrations in sera samples showed a significant decrease for calcium ion at pHs 5.5 and 4, while magnesium concentration was significantly decreased only at pH 4 compared to control group (P<0.05). Crayfish exposed to pH 2.5 died within 24 hours post-exposure.
  • G.H. Vossoughi, M.R. Ahmadi Pages 103-120
    Pleuronectiforme fishes of the Persian Gulf coastlines along Khuzestan, Bushehr and Hormozgan provinces were morphometrically and meristically studied from April 2003 to September 2005, in order to identify species. In this experiment, 1551 fish samples were caught by trawl or collected from fish markets. The sampling was carried out in 27 regions seasonally. Thirty six traits and parameters including 18 morphometric, 11 meristic, and 7 phenotype characters were determined. Data obtained from morphometric parameters were analyzed and dendrograms were designed using cluster method. Comparision of the biometric data with the checklist identification index of species show that there are 6 main and dominant families including: Bothidae, Psettodidae, Citharidae, Soleidae, Cynoglossidae and Paralichthyidae in the area. In addition, the identification of above- mentioned families indicated that 25 species in Khuzestan area, 19 species in Bushehr area and 16 species in Hormozgan area inhabit the coastal waters of the Persian Gulf. Meanwhile, 13 species from 5 families in Persian Gulf that have not been reported so far are identified and reported in this research. According to these results and comparing with other studies, 30 species from 6 families were identified in coastal waters in the Persian Gulf on Khuzestan, Bushehr and Hormozgan areas which is the most complete study in Persian Gulf.
  • M. Yousefian Pages 121-136
    The heritability response for growth of rainbow trout during early developmental stages was detected on the basis of full-sib and half-sib cross between the selected lines. The experiment was done in Shahid Bahonar Salmon Propagation Center, Kelardasht, Iran. Breeders were taken from the stocks maintained in this station. A bifactorial cross was done between two line using four randomly sire and four randomly chosen dams form each line Analysis of variance revealed a significant difference at 300 days of age between half and full-sib (P<0.026). The effective difference in weight between half/full-sibs of juveniles was not statistically significant on 150 days (P>0.817) and 225 days (P>0.081). No significant difference between mean body weight of male and female half-sib group was found (P>0.05); neither were there significant differences between sireline (P<0.324) and dam line (P<0.230) at age of 300 days.The heritability ranged from 0.093 to 0.223 in sire and 0.11 to 0.329 in dam groups. The average heritability in sire regardless of age was 0.16 and in dams 0.21. The heritability in total regardless of age and sex was estimated about 0.185. Genetic parameters (h2) were different between dams (0.15-0.27) and sires (0.13-0.19) for all ages of samplings and for age of 150 day old, was significant (P<0.035).