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    Effect of a fishing closure on Chamelea gallina stocks along the Turkish coast
    (Cambridge Univ Press, 2023) Dagtekin, Murat; Dalgic, Goktug; Erbay, Murat; Akpinar, Ilkay Ozcan; Aydin, Mehmet; Ozdemir, Süleyman; Karayucel, Sedat
    The striped venus clam Chamelea gallina (SVE), plays an important role as an infaunal filter-feeder in the ecosystem, besides an important economic role in the Black Sea coasts of Turkey. It is caught using hydraulic dredge boats, then processed, and the final product (frozen meat) is exported to EU countries. SVE fishing requires a special licence and regulations. Also, SVE beds were closed to fisheries for the recovery of stocks for 2 years. In the study, SVE beds were investigated during the closed season over two years to assess stock density. Additionally, the number of macrobenthic species that share the same habitat as the SVE was determined. The sampling area was divided into five sub-areas and four strata by depth and then stratified random sampling was applied to collect data. In 2011, SVE stock sizes in the sub-areas were 11,723.58 +/- 5167.262 tons (Cide), 35,082.94 +/- 27,510.95 tons (Inebolu), 10,077.05 +/- 4970.68 tons (Turkeli), 3304.36 +/- 3215.1 tons (Ayancik) and 1431.3 +/- 1703.5 tons (Sarikum). In 2012, these estimated stocks were 13,820.41 +/- 6977.86 tons, 34,841.94 +/- 14,623.71 tons, 8148.27 +/- 5006.74 tons, 3420.72 +/- 3093.67 tons and 2023.74 +/- 2832.63 tons, respectively. However, the estimated SVE total biomass did not change significantly during the period when the fields were closed (P > 0.05). The results indicate that length-weight relationship parameters varied of b from 2.9011-2.9072 in two years. Shell damage during fishing, environmental factors, food competition and consumption by the main predator all have a significant impact on stock densities, and changes occurring in these conditions should be considered in fisheries management.
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    Population abundance and growth parameters of an exotic bivalve species, Anadara kagoshimensis, in the Southwestern Black Sea
    (Tubitak Scientific & Technological Research Council Turkey, 2023) Dagtekin, Murat; Dalgic, Goktug; Erbay, Murat; Akpinar, Ilkay Ozcan; Aydin, Mehmet; Ozdemir, Suleyman; Cebeci, Ayse
    Blood cockle (Anadara kagoshimensis ) is an Indo-Pacific species that later entered the Black Sea. The abundance of A. kagoshimensis, which is not subjected to commercial fishing, is important in terms of food competition with other bivalvia species. Baby clam (Chamelea gallina) together with the A. kagoshimensis are dominant bivalve species found in the sandy and muddy areas off the coastal waters of the Black Sea. In this study, specimens of A. kagoshimensis have been recognized by morphological analysis and also confirmed by molecular characterization. Furthermore, the abundance and growth parameters of A. kagoshimensis were investigated in the Southwestern Black Sea. Blood cockles were sampled between February 2011 and December 2012, seasonally. According to the Von Bertalanffy Growth Parameters (VBGP) the results were L infinity = 81.96 mm, K = 0.32 year-1, t0 = -0.22 year, and nonseasonal L infinity = 84.32 mm, K = 0.31 year-1, t0 = -0.21, WP = 0.65, ts = 0.15. The growth pattern showed the slope [b] = 2.96-3.01 in 2011 and 2012. The stock size was estimated according to two different years in 5 different subareas (Cide, Inebolu, Turkeli, Ayancik, and Sarikum) and by 4 different strata (0-5 m, 5-10 m, 10-15 m, and 15-20 m). Considering subareas, the A. kagoshimensis population in all subareas increased significantly in a single year. Compared to other regions, Inebolu was the main highly distributed area of the A. kagoshimensis, and also the estimated stock size was the highest in the region. Due to food competition with other commercial species (mainly Chamelea gallina) A. kagoshimensis is an ecology important species for the Southern Black Sea habitats. It is aimed to make contributions to Good Environmental Status (GES) and fisheries management in the region.