Abstract
In this study, different levels of vitamin C (L-ascorbyl-2-polyphosphate) on the hatching efficiency and obtained Artemia nauplii survival were examined at different temperatures. In the first experiment, the effect of different amounts of vitamin C (0, 500, 1000 ppm) on hatching percentage of the Maharloo ...
Read More
In this study, different levels of vitamin C (L-ascorbyl-2-polyphosphate) on the hatching efficiency and obtained Artemia nauplii survival were examined at different temperatures. In the first experiment, the effect of different amounts of vitamin C (0, 500, 1000 ppm) on hatching percentage of the Maharloo Lake Artemia cyst was examined with 6 replicates. Results of the first experiment showed that different amounts of vitamin C had no significant effect on hatching percentage. In the second experiment, the effect of different temperatures on the percentage of survival of Artemia nauplii was studied. In this experiment, obtained nauplii from first experiment were put in 3 different temperatures (1, 4, 16 ºC) with 6 replicates for 48 hours, then percentage of survival of Artemia nauplii accounted. Result of the second experiment showed that interaction of vitamin C and different temperatures had no significant on the survival rate of Artemia nauplii. Different amounts of vitamin C (0, 500, 1000 ppm) had no significant difference on the percentage of survival of the Artemia nauplii, but different temperatures had significant effect on survival rate. Results of these experiments showed that increase of the amount of vitamin C had significant difference on hatching percentage of the Maharloo Artemia cyst, no significant effect on survival rate of Artemia nauplii. Also it is found that survival rate of Artemia nauplii in 16 ºC temperatures was more than 1 and 4 ºC temperatures.
Samaneh Poursaeid; Bahram Falahatkar; Iraj Efatpanah
Volume 11, Issue 2 , November 2012, , Pages 25-35
Mahmoud Shakoorian; Bahram Falahatkar
Volume 10, Issue 1 , September 2012, , Pages 32-43
Abstract
Availability of brood fish with high quality is one of the main aspects in sturgeon rehabilitation programs. The present study was conducted to compare different biological parameters and reproduction indices in 397 of Persian sturgeon broodstocks caught in the Sefidroud River and the Caspian Sea using ...
Read More
Availability of brood fish with high quality is one of the main aspects in sturgeon rehabilitation programs. The present study was conducted to compare different biological parameters and reproduction indices in 397 of Persian sturgeon broodstocks caught in the Sefidroud River and the Caspian Sea using beach seine and gillnets. A total of 74 Persian sturgeon broodstocks were caught in the Sefidroud River, and in the sea 199 spawners were collected using beach seine and 124 collected using gillnets. Results obtained showed that the minimum mean weight (26.5 ± 5.1 kg) recorded belonged to fish caught in beach seine whereas maximum mean weight (30.0 ± 4.0 kg) recorded belonged to fish caught in the river which were significantly different (P<0.05). No significant differences were detected in the weight of gonad from different groups of broodstocks (P>0.05). The highest polarization index (PI) (10.6 ± 2.6) in broodstocks belonged to the groups caught in beach seine and minimum PI values (6.6 ± 0.9) were observed in broodstocks caught in the river (P<0.05). Highest fertilization rate (92.2 ± 3.3 %) belonged to broodstocks caught in the river which was significantly higher than broodstocks collected from the sea (75.1 ± 4.8 %) (P<0.05). It is evident from the results obtained that higher values for reproduction indices were recorded in broodstocks caught in the river. Therefore, it is suggested that in order to improve artificial breeding programs in hatcheries and also to increase fertilization rate and survival rates of eggs and larvae, more attempts should be made to facilitate the migration of these spawners into the Sefidroud.