Shipwrecks are not the ultimate attracting features in a natural marine environment-the case of Karaburun, Turkey.

Shipwrecks attract divers. Therefore, decommissioned marine vehicles are used as artificial reefs for recreational diving tourism around the world. We examined divers' attitudes towards shipwrecks and their function as an ecological enhancers. The study was carried out in the Karaburun Peninsula, Turkey, where two passenger ships were sunk as artificial wreck reefs to attract diving tourism. Using a questionnaire survey accompanied by face-to-face interviews, of both certified divers and non-certified discovery divers we collected information about divers reefs preferences, perception of artificial reefs as well as their socio-demographic characteristics, dive experiences etc. Differences in divers' wreck (historical or artificial) and reef preferences (natural reefs or artificial wrecks) were analyzed with the Mann-Whitney U test. Overall, divers held the position that artificial wreck reefs provide ecological benefits on fish diversity and stocks (p < 0.05), and experienced divers supported this position more that novice ones. However, experience and number of annual dives did not affect this notion. Non-certified respondents were mostly neutral towards the ecologic and management statements. However, the majority of divers (84%) preferred to dive on natural reefs rather than on shipwrecks. Similarly, most of them (83%) preferred diving to historical shipwrecks which sank in wars or accidents, and not on ships intentionally sunk as attractions. These findings, which are in line with previous literature, put a question mark on the growing practice of sinking nearly any ship to create diving attractions.

Temporal trends of some trace metals in Lithophaga lithophaga (L., 1758) from Izmir Bay (Eastern Aegean Sea).

This study compared the levels of the trace metals zinc (Zn), cadmium (Cd), lead (Pb) and copper (Cu) in the bivalve Lithophaga lithophaga from Izmir Bay (Aegean Sea) between 2001 and 2011. Comparisons were made on the basis of season, as well as year. All values were measured by voltammetry. Median values of trace metals for all seasons in 2011 were 244.67 µg Zn g(-1), 1.09 µg Cd g(-1), 7.64 µg Pb g(-1) and 56.03 µg Cu g(-1) as dry weight. The results showed a general trend of decreasing Zn, Pb and Cu concentrations over time, but an increasing trend for Cd. Mean trace metal concentrations in individuals of L. lithophaga in 2011 exceeded the permissible limit published in the Turkish Food Codex for Pb, and closely approached the limit for Zn. The mean Cd concentration was within the permissible limit of the Turkish Food Codex, but exceeded the limit of the World Health Organization. Levels of Cu were within permissible limits of published regulations.