Showing 3 results for Caspian Sea
Volume 8, Issue 2 (10-2009)
Abstract
The Caspian sea as a unique habitat has accommodated Rutilus frisii kutum for as long as the course of history but has undergone extreme ecological & managerial disturbances over the recent centuries which has in turn, borought about dire consequences including the formation of a potentially fragile ecosystem. In fact, various researches undertaken on this issue has shown that the specter of such ominous changes in ecosystem and the living resources of the Caspian Sea loom near. The present study aims at investigating the sexual and biological aspects of fish &their sex organs in Rutilus f. Kutum along the southern coasts of the Caspian Sea. To this end, the fish and gonad samples of Rutilus f. kutum migrating to rivers & estuaries were collected & analyzed through sampling procedures based on fish gonad. Upon treating the samples with Bouin & the related preparations, (I.e. extraction of water, making from the sample them transparent, molding & doing them based on H&E method), , whereas Peterson correlation coefficient was applied for toxic variables. The results of the analysis shows that 45 percent of sampled fish with an average length of (349 58) mm weighing 564 334) were male and 54.4 were Females. The sexual maturity rate, as specified by the six stages analysis me Thad of Johnson’s (Johnson’s, 1970) in dictated the position of female in the stages: IV & V during March, April & June. 32% of female fish were in stage V & %68 in stage IV in March whereas the percentages of female fish in April was %87 in the stage V followed by %94 in the stage V during June.
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Volume 13, Issue 1 (5-2013)
Abstract
For this purpose 5 sampling stations namely as Astara, Bandar Anzali, Hashtpar, Chaboksar and Bandar Kiashahr were selected along the shoreline of the southwest Caspian. The maximum density was observed in 3-15 m depth. Catch composition from different sampling sites approve this statement. 0.41%, 2.24%, and 2.59% out of total catch was starry goby that came from Bandar Anzali, Chaboksar and Astara sampling stations respectively. This species did not observe in the Hashtpar and Bandar Kiashahr sampling stations. According to the results mean total length was 61.28±16.14 mm and mean weight was 3.16±0.92 gr.
Volume 18, Issue 49 (11-2006)
Abstract
222 prespawning adult Acipenser persicus including 178 female and 44 male were sampled for studying the effect of temperature on the artificial breeding in the southeast of the Caspian sea during march 2000 – May 2001. The samples breeded in the shahid Marjany, sturgeon breeding and propagation center in Gorgan. In this study, the effect of temperature on fertilization percentage, the time of female sex ripering, positive feedback of broodstock to injection of pituitary studied. To study the effect of temperature on fertilization percentage, the time of female sex ripering, temperature groups divided into three groups and also to study the effect of temperature on the positive feedback of broodstock to injection on pituitary the temperature groups were divided into four groups. The highest fertilization percentage observed in 16.1-18°c. Increasing the temperature declined the time of female ripering of sexual maturity and positive feedback to pituitary injection
