Ali Reza Shamoradi; Mohammad Ali Salari-Aliabadi; Seiied Mohammad Bagher Nabavi; Ahmad Savari; Abdolali Movahedinia
Volume 11, Issue 2 , November 2012, , Pages 8-15
Abstract
The goals of this study were identification and ecological survey on macrobenthic bivalves in the Khark Island. This study has been done during four seasons through 2010-2011 in five sites around the Khark Island. In each five sites, three separated transects including supralittoral, eulittoral and sublittoral ...
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The goals of this study were identification and ecological survey on macrobenthic bivalves in the Khark Island. This study has been done during four seasons through 2010-2011 in five sites around the Khark Island. In each five sites, three separated transects including supralittoral, eulittoral and sublittoral zones have been selected. At each sampling time and site environmental factors such as temperature, salinity and total organic maters (TOM) have been measured. Collected samples were analysed and according to the results, Maximum and minimum water temperatures have recorded in summer (35.94 ± 0.28) and in winter (18.34 ± 0.39) and the Maximum and minimum rates of salinity have recorded in winter (44.6 ± 0.14) and spring (37 ± 0.18) respectively. Maximum and minimum percentages of total organic maters (TOM) have observed in summer (9.63 ± 0.71) and winter (3.39 ± 0.15) respectively. Twelve bivalve species belonging to seven families were identified that are: Barbatia lacerate, Pinctada radiate, Ostrea sp.1, Crossostrea gigas, Sacosstrea cucullata. Diplodonta ravaiyensis, Venus sp.1, Circentia callypyga, Callista sp.1, Gari roseus, Tellina capsoides, Angulus adensis. The maximum and minimum density and distribution have been found in spring and summer respectively. In our study the most frequent bivalve species in all seasons was Barbatia lacerate.
علوم زیستی دریا
Gholamreza Eskandari; Ahmad Savari; Perita Kochanian; Aseiied aminollah Taghavi Motlagh
Volume 11, Issue 1 , November 2012, , Pages 49-57
Abstract
In the present study, length structure, mortality and exploitation rate of Otolithes ruber during a ten-year period were studied. Sampling was carried out by using bottom trawl net in the fishing area in Northwest of Persian Gulf over 1 year study period. Length data was also collected from fisheries ...
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In the present study, length structure, mortality and exploitation rate of Otolithes ruber during a ten-year period were studied. Sampling was carried out by using bottom trawl net in the fishing area in Northwest of Persian Gulf over 1 year study period. Length data was also collected from fisheries research institute and fishery organization. Age determination was done by reading annual rings on sectioned otolith. Growth parameters were calculated based on age and length data. These data were used to estimate natural mortality rate. Total mortality was obtained from the age curve. Logarithmic catch and natural mortality were calculated from Pauly's equation. The averages of length in the last ten years were 35 to 39 cm. The samples ranged in length from 12 to 58 cm with the maximum frequencies between 28-44 cm. Length distribution was normal in this study. The maximum catch was composed of fish in the 40 to 48 cm length range with an average age of 2 to 3 years. The average total mortality, natural mortality and fishing mortality were 0.98, 0.56, and 0.42 respectively. Mortality was higher in age group 0 and age group 1, but mortality of the other age groups dramatically decreased. Exploitation rate in the last ten years were 0.42 indicating a near complete exploitation. Based on the results a more effective exploitation strategy is suggested in this region.
Fatemeh Einolahi; Alireza Safahieh; Ali Ali Dadollahi sohrab; Ahmad Savari
Volume 10, Issue 2 , September 2012, , Pages 10-25
Abstract
In order to understand the extent of heavy metals contamination in sediments and rock oyster Saccostrea cucullata, of Chabahar intertidal zone, samples of sediment and oyster were collected from 5 different stations namely Guatr, Beris, Ramin, Shahid Beheshti and Tiss during low tide. Sediment and tissue ...
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In order to understand the extent of heavy metals contamination in sediments and rock oyster Saccostrea cucullata, of Chabahar intertidal zone, samples of sediment and oyster were collected from 5 different stations namely Guatr, Beris, Ramin, Shahid Beheshti and Tiss during low tide. Sediment and tissue samples were acid digested and heavy metals content of the samples were analyzed. Results showed that Cu, Pb and Ni concentration in the sediment samples was 15.87-16.96, 10.98-15.79 and 12.39-17.10 µg/g, respectively. Heavy metals concentration in soft tissues of oyster was 84.96-289.93, 3.83-5.26 and 6.05-7.19 µg/g for Cu, Pb and Ni ,respectively. Similarly, Cu, Pb and Ni concentration in shell ranged between 13.83-6.67, 11.32-14.93 and 5.97-7.97 µg/g, respectively. No significant difference was found between Cu and Ni concentrations in sediment samples. It is suggested that metals accumulation in different oyster tissues was related to their essentiality for oyster. Heavy metals concentration in oyster and sediment was found to fall within the range of some available standards, indicating that metals contamination does not seems to be problematic in the area.
Aali Hosseini; Preeta Kochanian; Jasem Ghofleh Marammazi; Vahid Yavari; Ahmad Savari
Volume 10, Issue 2 , September 2012, , Pages 26-36
Abstract
A total of 311 specimens were collected from November 2006 to October 2007 . We estimated Population parameters from length frequency data. These cases consist of the von Bertalanffy growth parameters and mortality, as well as exploitation rate. The result indicated that pickhandle ...
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A total of 311 specimens were collected from November 2006 to October 2007 . We estimated Population parameters from length frequency data. These cases consist of the von Bertalanffy growth parameters and mortality, as well as exploitation rate. The result indicated that pickhandle barracuda had L∞ =109.21 cm total length, K=0.37 and theoretical age at zero length, = -0.5 The total mortality rate (Z) was estimated to be 1.91, the fishing mortality rate (F) and the natural mortality(M) were 1.30 and 0.61, respectively. The exploitation rate (E) was 0.68. The exploitation rate indicated that the stockis in high pressure of catch and overexploited.