Effect of a fishing closure on Chamelea gallina stocks along the Turkish coast

Abstract

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.