Spawning Frequency of Trachurus mediterraneus (Carangidae) in The Sea of Marmara

Abstract

In this study the spawning frequency of Trachurus mediterraneus was estimated for the first time in the Mediterranean basin. The presence of the late-migratory nucleus stage oocytes and post ovulatory follicles (POFs) in the same ovaries were observed continuously during the sampling period. The daily percentage of spawning females with ovaries containing: late migratory nucleus (MN) stage, POFs (present up to 12-24h from the spawning event) was calculated as 11.7% and 18.6% respectively. The average percentage of females presenting one of the two different states was 15.3% which indicated that Mediterranean horse mackerel had high spawning rates in the Sea of Marmara. Our results indicated that T. mediterraneus is a multiple spawner and females spawn approximately every 6.6 days, therefore 20 times in the spawning period May-August 2009.