Review of the distribution of large sharks in the seas of Turkey (Eastern Mediterranean)

Abstract

Observations carried out in the seas of Turkey between 1990 and August 2015, allowed to record in the area 392 large sharks including 10 families, 13 genera and 18 species. Hexanchus griseus was the predominant species, comprising 169 specimens and 43.2% of total captures. Analyses on the periodicity of the captures of large sharks from the seas of Turkey during the last 25 years revealed an increasing trend in annual catches since 1990, which was statistically significant (p < 0.001). Based on catch records from the last 25 years, 342 (87.2%) specimens were recorded after 1990. A peak of annual number of catches was observed in 2012. The highest numbers of large sharks were recorded from the Sea of Marmara (n =151; 38.6%), the Aegean Sea (n =121; 30.9%), the Levantine Sea (n =114; 29.1%), and the Black Sea (n = 5; 1.2%), respectively. Of the 392 large sharks recorded in Turkish waters, 128 (32.6% of total records) were obtained via internet sources, such as social media, spearfishermen forums, maritime news websites. The role of these latter categories of information cannot be totally ruled out in monitoring of large shark captures in the future.