Assessment of Exploited Stock and Management Implications of Tiger Tooth Croaker (Otolithes ruber) in Coastal Waters of Makran, Pakistan

Pakistan’s marine fishing industry is crucial to the country’s economy, generating employment opportunities and foreign revenue. It produces 80% of the country’s total fish production. Otolithes ruber is a commercially important fish on the Makran coast of Pakistan, contributing significantly to the region’s croaker fisheries. This study is the first to apply three length-based approaches for assessing the stock status of O. ruber in the Makran coast: (1) TropFishR to estimate the mortality, growth parameters, and current exploitation status, reference points based on the yield per recruitment model, (2) the length-based Bayesian biomass method (LBB) to calculate stock biomass, and (3) the length-based spawning potential ratio (LBSPR) to estimate the spawning potential ratio. The length–weight relationship of Otolithes ruber was a positive allometric pattern (b = 3.28; R2 = 0.94). Growth parameters for Otolithes ruber were L∞ = 55.47 cm, K = 0.50 year−1. The calculated total mortality rate (Z), natural mortality (M), and fishing mortality (F) were 2.27 year−1, 0.67 year−1, and 1.6 year−1, respectively. The exploitation rate (E) was 0.70, indicating severe overexploitation. The current length at first capture (Lc50) = 27.37 cm was lower than that at first maturity (Lm50) = 30.75 cm, indicating growth overfishing. The current spawning potential ratio (8%) was lower than the optimal value (40%), indicating recruitment overfishing. The current biomass, concerning virgin biomass B/Bo, was also 8%, resulting in a 92% stock decline. We recommend reducing the exploitation pressure by limiting the commercial catch to an optimum length range of 34.5–42.2 cm and reducing fishing pressure by 40% to ensure sustainable fishery management.