Population pattern and dynamics of the Bluemouth Helicolenus dactylopterus (Delaroche, 1809) in the eastern Mediterranean Sea

Present study evaluated the population status of the Bluemouth (Helicolenus dactylopterus) population distributed in the Antalya Bay for the first time, within the scope of two different surveys carried out in monthly basis, between September 2009 and June 2011 (200–900 m). In accordance with the major availability of the food, 80.9% of the total catch (in number) of the species at the upper slope (200–499 m). The 80.8% of all recruits’ specimens inhabits between 200 and 399 m while 72% of the total spawner specimens (TL ≥ 20 cm) inhabits at depths of between 600 and 799 m. Highest average abundance of the species was estimated 1,060 n/km² (400 m), while the highest average biomass was 93 kg/km² (600 m). Lengths of individuals ranged from 4 to 36 cm, and estimated ages from 0 to 27 years. Parameters of the von Bertalanffy growth curves were L _∞   = 34.14 cm, K = 0.09 year^?1, and t₀ = ?1.28 years. Margin band analysis confirmed the formation of a single growth annulus per year. In the central part of the otolith, close to the nucleus, a strongly marked check ring is formed which presenting first time for this species in the literature. The duration of the spawning stage for the females was observed between December and February. Selectivity rate of the commercially used 44 mm diamond codend mesh, with a 7.4 cm catch size, found to be very low for the species (a first spawning size of 17–20 cm). The stock of Bluemouth in the Antalya Bay was considered in above reference levels and in high abundance status due to estimated low fishing mortality (0.067^?1), exploitation rate status below reference level (0.207^?1) and F_curr is very low than reference point (0.219^?1).