Spatio-temporal patterns of abundance, biomass and length-weight relationship of white grouper, Epinephelus aeneus (Geoffroy Saint-Hilaire, 1817) (Pisces: Serranidae) in the Gulf of Antalya, Turkey (Levantine Sea)
Elif Özgür Özbek, Turhan Kebapçıoğlu, Mine Çardak
Antalya Metropolitan Municipality, Department of International Relations, Directorate of European Union Relations and Projects, Antalya, TURKEY
Faculty of Fisheries, Akdeniz University, 07058, Antalya, TURKEY
Faculty of Fisheries, Çanakkale Onsekiz Mart University, 17100, Çanakkale, TURKEY
The present paper reports the abundance and biomass of white grouper, Epinephelus aeneus (Geoffroy Saint-Hilaire, 1817), (Pisces: Serranidae) according to depth levels and seasons in the Gulf of Antalya, and the length-weight relationship parameters of 350 individuals. A total of 116 hauls were carried out, between August 2009 and April 2010, seasonally in the Gulf of Antalya, at six stations and six depth levels (25, 50, 75, 100, 150, 200 m), using a commercial bottom trawl. E. aeneus was sampled from 60 hauls and the frequency of occurrence was 51.72%. The overall average biomass of E. aeneus was 55.78 kg/km2 and the mean abundance was 60.60 ind./km2 .The smallest total length (TL) was 10 cm and the maximum TL was 101 cm. The mean TL was calculated as 34.99 cm. The general length-weight relationship was described by the equation: W = 0.040*L2.657 (r2: 0.958; p<0.001). Mean TL and weight of the specimens, b-value and mean biomass per abundance were highest in summer. The mean biomass per abundance was higher in Sts. D, E and F than Sts. A, B and C, located in the eastern part of the gulf. The mean abundance decreased as the depth level increased, however, mean biomass per abundance and mean TL and weight of the individuals increased constantly from 25 m to 100 m depth. The percentage of the mature fish decreased as the depth decreased.
Keywords: Epinephelus aeneus, white grouper, seasonal trawl survey, Antalya, Mediterranean Sea, length-weight relationship