Red Mullet (Mullus barbatus ponticus Essipov, 1927) Stock Exploitation in Georgian Coastal Waters (2019-2021)

Abstract

The aim of this study is to assess the level of the red mullet stock exploitation in Georgian coastal waters using the CMSY, LBB and LB-SPR modeling methods. The samplings were carried out using bottom trawls in 2019-2021. In total 4957 individuals were sampling (1 508 cases age was determined using scales and otoliths). Average annual catch of the red mullet make up 11.7±3.3 t (0.3% of the total annual Black Sea countries landings). The total length ranged from 6.1 to 20.7 cm. 70% of landings consisted of 3+, 4+ and 5+ age. The length-weight relationship was calculated as W=0.0072 × L3.20. Average von Bertalanffy growth parameters were L∞=18.00±0.27 cm, k=0.31±0.03, and t0= –0.93±0.26. LBB method demonstrate that the red mullet stock was overexploited (F/M=2.7 more than optimal level F/M=1.0). According to CMSY analysis, biomass has been decreasing to Blim for the researched period. The LB-SPR result showed that the estimated SPR was 23%. The exploitation of the stock was steadily intensive according to CMSY and LB-SPR methods. Increase in fishing mortality is not recommended.