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

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 x L3.20. Average von Bertalanffy growth parameters were L infinity=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.

Automated summary

The aim of this study was to assess the level of red mullet stock exploitation in Georgian coastal waters using CMSY, LBB, and LB-SPR modeling methods. Bottom trawls were used for samplings conducted from 2019 to 2021, with a total of 4957 individuals sampled. The findings suggest that the red mullet stock was overexploited according to the LBB method, and biomass has been decreasing based on CMSY analysis.