Research Article: Length based spawning potential ratio (LBSPR) of javelin grunter, Pomadasys kaakan (Cuvier, 1830) in the Persian Gulf and Oman Sea

Length-Based Spawning Potential Ratio (LB-SPR) model was applied to describe the status of Javelin grunter, Pomadasys kaakan in the Persian Gulf and Oman Sea. From April 2002 to March 2019. 45,489 specimens were collected from fish landing sites monthly, and their length (FL) and weight were measured. The results of the present study showed that different gears captured most of the P. kaakan before first spawning time. The maximum-recorded length for this species in the study area was 60 cm FL with a mean length of 43.0±4.73 cm. The M/K value corresponds to P. kaakan maturation was calculated as 0.53. Based on the LB-SPR assessment model, it could be concluded that these species become vulnerable to fishing at its maturation’ size (48 cm). The range of annual SPR of P. kaakan was estimated between 0.14 to 0.18 in the Persian Gulf and Oman Sea (Iranian waters), which is even lower than the threshold value of 0.2. Such results suggest that the exploitation of P. kaakan occurred above the maximum sustainable limit and has a confounding effect on successful recruitment and juvenile survival of this species. The Spawning Potential Ratio of P. kaakan based on time series analysis, as a biological reference point was estimated below 0.2, which means for achieving a higher SPR level and sustainable fisheries, the rate of fishing mortality should be reduced constantly.