Evaluation of the age structure and population dynamics of Saurida tumbil inhabiting Hormuz strait from Kolahi to Dargahan

Abstract

Introduction: This study investigated the age, population dynamics and some biological characteristics of Saurida tumbil inhabiting Hormozgan province from Kolahi to Dargahan.
Materials & Methods: This study was based on the data obtained from commercial catches of shrimp trawl vessels in fishing seasons of 2019.
Result: The results of this study showed that the highest correlation was related to total length and fork length relationship with estimated coefficient of correlation (r2= 0.9988). Also the results showed a significantly correlated length-weight relationship with estimated coefficient of correlation (r2= 0.9373). The value of the slope (b) was significantly different from 3 which shows a negative allometric growth for this species. The estimated age (based on vertebrae age reading method) variability were 1 to 7 years. The fish with age 2 showed the highest frequency among the age groups. Also the Bertalanffy growth equation for this species in the study area was estimated as Lt=50.02 (l-exp(-0.28 (t+0.27)). The mortality coefficients were 2.66, 0.67 and 1.99 for the total mortality "Z", natural mortality "M" and fishing mortality "F", respectively. Also, the estimated exploitation rate for this species was 0.75 which shows that this species is in overexploitation phase.
Conclusion: To improve the present stock status in this area and sustainable capture of S. tumbil, it is recommended to decrease fishing effort and improve bottom trawl for reducing bycatch issues.