Georgi Rusenov and Angelina Ivanova
Agricultural Academy – Sofia, Institute of Fisheries and Aquaculture – Plovdiv, Bulgaria
Rusenov, G. & Ivanova, A. (2025). Size-weight structure of plain (Psetta maxima) in the Bulgarian Black Sea aquatoria. Bulg. J. Agric. Sci., 31(6), 1220–1223
Turbot (Psetta maxima(Linnaeus, 1758) is a demersal fish. It is widespread in all countries bordering the Black Sea. Turbot is one of the most valuable commercial fish species, with high demand and a corresponding high price. Higher catches are recorded in spring and autumn. In the Black Sea, it inhabits the coastal zone, particularly on sandy or muddy bottoms, and is found at depths of up to 100 m. It lives up to 10–12 years. It grows up to approximately 90 cm and reaches a weight of up to 15 kg. The breeding season is between April and June. Several local populations represent the black Sea turbot. The fish is not a highly migratory species, but it seasonally moves to coastal areas where it is introduced to spawn, feed, or winter (Hubenova et al., 2015).
The assessment of the collection of fish stocks for the Black Sea in recent years in the sector is carried out within the framework of the implementation of the scientific studies (Petrova et al., 2023; Lazarova et al., 2023), that Bulgaria is obliged to perform, according to the Work Plan for the collection, management and use of data „Fisheries“ for the purposes of scientific analysis and the implementation of the Common Fisheries Policy. The institutes responsible for and implementing this activity are the Institute of Fish Resources, Varna, the Agricultural Academy, Institute of Oceanology, Varna, BAS, and the Institute of Fisheries and Aquaculture, Plovdiv. The Institute of Fisheries and Aquaculture in Plovdiv has been monitoring turbot landings since 2014. Object of analysis of the size-weight characteristic, age, sex ratio, degree of maturity of the reproductive system, fertility, etc., of the specimens caught and landed.
The study spans the period from 2019 to 2022. Within the framework of the contracts with the Executive Agency of Fisheries and Aquaculture for monitoring, the Institute of Fisheries and Aquaculture’s team registered 152 turbot landings. 3370 fish with an average size of 54.44 cm and an average weight of 2.88 kg were analyzed. Maximum production value of 9.75 kg and minimum of 1.40 kg. On the basis of the data presented in this way, we assume that a significant share of the catches consists of fish with a relatively low weight. Future studies may confirm or reject this suggestion.
The impact of size is essential in the direction of weight in the studied specimens. A very strong positive correlation was shown between length (TL) and turbinate weight (BW). The regression equation is: W = 5,86 + 0,16 TL.