Population structure and distribution of sea snail, Rapana venosa, in the Southern Black sea (Ri̇ze coast)

This study has been made by using Beam Trawl in 5-30+m dept, was carried out in Rize-Merkez, Çayeli and İyidere area between December 2012 and November 2013. While the study following results were found: The length of rapa welk (Rapana venosa) population was variable between 10.29 mm and 99.23 mm. The average lenght of the population is 40.84±0.33 mm whereas the average weight is 18.10±0.53 g in İyidere area. According to the study for the same population, lengths were vary between 7.72 and 123.04 mm, the average length was 39.52±0.25 mm whereas the average weight is 16.73±0.39 g in İyidere area. In the center of Rize, length of the population was variable between 8.01 mm and 119.54 mm and the average length is 39.79±0.31 mm whereas the average weight was 16.73±0.39 g in the center of Rize. For Çayeli area, the correlation that between lenght and weight is calculated by W=0.0001L3.2843, for İyidere: W=0.00029L2.907 and as a last area, center of Rize: W=0.0001L3.2732. Rapa welk population was mostly seen in depth by 20-30+ min the center but for İyidere and Çayeli, the depth was between 10 m and 20 m. If we have a look population dispersion which was realeted to seasons, there was no doubt that in İyidere, population is higher than other areas in the spring and summer season. The population is high in the summer and autumn season in all areas.