مقايسه شاخص هاي طول ، وزن ، سن و خاوياردهي بين گونه تاسماهي ايراني (Acipenser persicus) و تاسماهي روسي (A.gueldenstaedtti) در حوضه جنوبي درياي خزر

Comparison of length, weight, age and caviar removal indicators between Persian sturgeon (Acipenser persicus) and Russian sturgeon (Acipenser gueldenstaedtii)

The objective of this study is to investigate & compare some differences in parameters like fork length, age and caviar removal in two sturgeon species, Acipenser persicus and Acipenser gueldenstaedtii in order to separate them. During 1990 to 2002, totally 81963 specimens including 58239 Persian sturgeon and 23724 Russian sturgeon investigated to measure these parameters in southern coasts of Caspian sea (Iranian waters).To compare the difference or similarity in the mentioned parameters between the two species, we used Mann-Whitney-U Test- ver11. Statistical analysis of the mentioned parameters by Mann-Whitney in 99% confidence level showed significant differences in the parameters of length, weight, age and caviar removal between Acipenser persicus & Acipenser guldenstaedtii (male & female) (Asymp .Sig.(2-tailed=0). Also, the annual mean of these parameters was higher in Acipenser persicus compared to Acipenser gueldenstaedtii,_ so as during 13 years of study, the mean length of Acipenser persicus and Acipenser gueldenstaedtii was 149.2±14.9 cm and 130.9±13.6 cm, respectively. Moreover, the mean weight was 25.7±8.3 and 21.4±7.4 kg and the mean age was 15.7±2.5 and 14.1±2.4 years in Acipenser persicus and Acipenser gueldenstaedtii, respectively. The mean caviar removal was 4.9±1.8 kg in Acipenser persicus and 3.9±1.7 kg in Acipenser gueldenstaedtii. During the study period, all these parameters were higher in male & female of Acipenser persicus compared to Acipenser gueldenstaedtii.