Mesogobius batrachocephalus can reach a maximum standard length (SLmax) 35 cm. There are two LWRs in the literature, covering size ranges from 5.5–18 cm TL. This result includes a new size range from 5.3 to 34.0 m TL. Salmo labrax can reach a SLmax of 80 cm. There is no LWRs in the FishBase and this estimate would be first data for database. Spicara flexuosum can reach 20 cm SL and reaches maturity around 9.1 cm. There are nine LWRs in the literature, covering size ranges from 6.5 to 20.0 cm TL. This study includes a new TLmax (25 cm) but so far, the r2 value of the estimate in this study is fairly low (r2 = 0.907). Umbrina cirrosa can reach 73 cm TL. There are only three LWRs in the literature, covering size ranges from 6.5 to 66.5 cm TL. This study shows a larger size range, up to 104 cm and the r2 value of the estimate in this study is reliable (r2 = 0.907).
The b-value of the 21 sampled species corresponded to the expected range of 2.5 < b < 3.5 (Carlander, 1969). The b-value for S. labrax and Spicara flexuosum fell out of the expected range. There were several variations in the computed b-value in the current study for a few species in contrast with the previous estimates that exist in the Black Sea literature (Kalaycı et al. 2007; Ak et al. 2009; Özdemir and Duyar 2013; Kasapoğlu and Düzgüneş 2014; Yeşilçiçek et al. 2015; Çalık and Erdoğan Sağlam 2017; Onay and Dalgıç 2021; Dağtekin et al. 2022) and database of FishBase (Froese and Pauly 2022). The key factor which influencing the b-value is sample size, depth of capture, length class, sex, maturity, hydrographical and physico-chemical parameter of the environment (Bagenal and Tesch 1978; Thomas et al. 2003; Hossain et al. 2009). These components were neglected in the current study and the noticed differences in LWRs parameters could be based on the effect of a single or multiple factor. It is thought that the difference between the LWR parameters is due to the selectivity and type of the fishing gears depending on the sampling methods, and the sampling season (Bautista-Romero et al. 2012; Moutopoulos et al. 2013).
In comparison with the previous studies, some little differences in r2 calculations in the current study were regular which may be based on many components such as season, length range, fish physiology, sampling size and habitat (Froese 2006). Despite the careful controls for outliers, the LWR estimates for the nine species marked with (*) in Table 1 should be considered tentative because of the relatively low values of the coefficient of determination (< 0.95). One reason the smaller size class are often missing is because it uses commercial fishing gears targeting legal size fish. The findings should be considered significant in the current study for species that exhibit a high levels of correlation (r2).
In conclusion, the key biological data presented in the current study contribute to filling in the gaps and can support the sustainable management of marine fish. Further studies involving additional size classes are highly recommended to help improve the species-specific LWR.