Changes in demographic parameters based on the length of tigertooth croaker (Otolithes ruber Bloch & Schneider, 1801) during two periods of time in the northern waters of the Oman Sea (Sistan and Baluchistan Province)

In order to investigate the changes in the population indices of Otolithes ruber fish during the years 1992 and 2022, the biometry of 3551 tigertooth croaker fish was done and the average length 42±8 cm and 38±7 cm, respectively. The average weight of this species was 642±130 grs in 1992 and 638±180 grs in 2022. The relationship between fork length and body weight for the year 1992, was W=0.012*L2.95 (R2=0.85, N=750) and for the year 2022, was W=0.05*L2.56 (R2=0.86, N=703). Von bertalanffy equation for this species in the northern waters of the Oman Sea (Sistan and Baluchistan Province) was calculated in 1992 and 2022, respectively as Lt =66 (1-exp (-0.41 (t +0.32)) and Lt =66 (1-exp (-0.59 (t +0.32)). The maximum sustainable yield (MSY) and the ratio of current biomass to initial biomass (B/BV or B/B0) in 1992 and 2022 was estimated as 1293 tons, 0.40 and 2417 tons, 0.35, respectively. The ratio of spawning potential based on length in 2022 and 1992 were 0.4 (0.36-0.44) and 0.5 (0.4-0.59), respectively. Based on data of decrease in the average length, increase of fishing, total mortality and ratio of the fishing mortality to the fishing mortality of the maximum sustainable yield (F/FMSY >1), it can be concluded that there are reasons for overfishing.