Evaluation of sprat (Sprattus sprattus (L. 1758)) stock in theCentral and Eastern Black Sea

In the study, the stocks of sprat (Sprattus sprattus (L. 1758)) in the Central and Eastern Black Sea region were monitored by the acoustic method and the stock status was summarized with the accepted stock evaluation models. According to the results, the growth parameters of the von Bertalanffy as average of the years 2017-2022 were found as L∞=13.40 cm, k=0.43, t0 = -1.370. First breeding length was estimated as 5.99 cm for females and 5.74 cm for males. The percentage of fish smaller than 5.74 cm among the sampled fish was determined as 0.65%. The average fish lengths determined by acoustically recorded data according to years (2016, 2017, 2018, 2019, 2021, 2022) was determined respectively as 7.1±1.95 cm, 7.6 ±2.22 cm, 5.8±1.41 cm, 6.9±1.31 cm, 7.2±1.82 cm and 6.9±1.63 cm. The biomass of sprat stocks in 1 mile2 was predicted according to years respectively as 1.24 tons/Nm2, 2.03 tons/ Nm2, 3.28 tons/ Nm2, 14.11 tons/ Nm2, 1.4 tons/ Nm2 and 0.76 tons/ Nm2. When the outputs of the models are examined, the spawning stock (SSB) for the year 2022 was calculated with XSA and SAM as 100 994 and 80 615 tons, the participation in the stock was 81 761 452 and 56 543 214 units, and the fishing pressure was calculated Fbar 0.42 and 0.8 year-1, and overfishing increased the use of the stocks above the reference level (Ebar). During 2016-2022, there were fluctuating decreases in RCC and prey due to fishing, and it was observed that the sprat made a cyclical oscillation every 5 years during its life period. This situation can be evaluated as the self-renewal period of the stock within the scope of ecological parameters and fishing activities. However, taking into account the stock situation and fishing in recent years, the stock utilization rate should be kept below the reference level.