Investigating Biological and Statistical on Sturgeon fish in 2001-2003

Abstract

In the present research experiments were conducted to evaluate the Sturgeons Stocks in south part of the Caspian Sea (Iranian side) by measuring different parameters such as CPUE, length , age , weight , sex and caviar weight. The biological samples were collected from 14 commercial landing center that were selected by cluster analysis. The total catch was estimated from the regression between flesh weight to total weight , catch per unit effort was estimated expressed in kg/day/100 gillnets. The changes in the sex composition and the average of length , weight , sex and the caviar rate of different species was discuesed. The catch amount of sturgeon fish during the years of 2001, 2002 and 2003 were 901, 666 and 475 tones, respectively. Catch and CPUE of all five spices showed descending trends. Sturgeon stocks descending trend has continued yet. For Persian Sturgeon in which was in a different stock situation; meanwhile the resources of juveniles and youngest ones are in a reasonable condition, but the amount of adults have been significantly decreased. Due to decrease of natural and artificial breeding during the decade of 1990, consequently the decrease of sturgeon stock is continued and it is assumed that this ascending trend is continued within next 5 years. According to the present situation of sturgeon resources and regarding to prevent the destroy of this resources , it is proposed to ban any fishing on sturgeon at least for 5 years and only to collect few brood stocks for artificial propagation and research studies.