Fecundity, spawning strategy and oocyte development of shortfin squid Alloteuthis media (Myopsida:Loliginidae) in the Eastern Mediterranean


Salman A.

CAHIERS DE BIOLOGIE MARINE, cilt.55, ss.163-171, 2014 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 55 Konu: 2
  • Basım Tarihi: 2014
  • Dergi Adı: CAHIERS DE BIOLOGIE MARINE
  • Sayfa Sayıları: ss.163-171

Özet

A total of 1,004 specimens of Alloteuthis media was collected by monthly samplings using a bottom trawl with a 44-mm mesh size. The depth range of trawls varied between 150 and 350 m. The maximum size (dorsal mantle length, ML) was 68 mm for males and 78 mm for females. Seasonal gonadal stages of both sexes were examined using a gonado-somatic index. Due to a bi-modal distribution of the oocytes in the gonad, the ovulation pattern of A. media is a group-synchronous type of ovulation and that spawning is continuous all year round. Two main reproductive peaks occur in the Aegean Sea, in April and in June. The potential fecundity of females ranged between 720 and 1284 oocytes. The smallest female with mature oocytes in the oviduct was 31 mm ML, while the biggest mature female was 78 mm ML. Size-at-maturity (ML50) of the population for males and females was 26-30 mm ML and 31-35 mm ML, respectively. This indicates an over fishing effect on A. media, as it also affects fish and forces them to early spawning.