Turkish Journal of Fisheries and Aquatic Sciences
2014, Vol 14, Num, 3 (Pages: 825-830)
On the Turkish Surface Longline Fishery Targeting Swordfish in the Eastern Mediterranean Sea
Tevfik Ceyhan 1 ,Okan Akyol 1
1 Ege University, Faculty of Fisheries, Bornova, Izmir, Turkey
DOI :
10.4194/1303-2712-v14_3_25
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This study presents the results based on catch per unit effort (CPUE) and incidental catch ratios of surveys on the
Turkish swordfish longliners during the fishing seasons between 2008 and 2013. A total of 50 surveying operations were
carried out, including 45 in Fethiye, 5 in Özdere in the southern Aegean coasts along the eastern Mediterranean Sea. A total of
217 (4061 kg) swordfish were obtained during 50 operations. The mean CPUEs for swordfish by number and weight were
computed as 10.8±1.59 specimens and 179.6±21.48 kg per 1000 hooks, respectively. Although, there was no significant
differences among means of CPUEs by number of swordfish (P>0.05), the CPUEs by weight of swordfish were significantly
different among years (P<0.05). A total of 14 species, belonging to 12 families (276 specimens; 5535 kg) were caught. The
target swordfish had the highest ratio both in number (78.6%) and in biomass (73.3%), followed by Mobula mobular, Alopias
vulpinus, Prionace glauca, Isurus oxyrinchus, Ruvettus pretiosus, Coryphaena hippurus, Thunnus alalunga by weight,
respectively. Biomass and number ratios of the non-target species to the target swordfish were 1:0.27 and 1:0.36, respectively.
A total of two specimens of which P. glauca (10 kg) and M. mobular (300 kg) were released lively and the others were
retained due to commercial value. A significant difference was not found between weight of by-catch species and weight of
the swordfish according to years (P>0.05).
Keywords :
Swordfish, Xiphias gladius, surface longline, incidental catch, Aegean Sea, Eastern Mediterranean