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Reproductive biology of Penaeus kerathurus (Forskål, 1775) (Decapoda: Penaeidae) in the Sea of Marmara, Turkey

Ihsanoglu Mukadder Arslan, Daban Ismail Burak, Işmen Ali, Cabbar Koray, Yığin Cahide Çiğdem

Oceanological and Hydrobiological Studies

2021

Vol. 50, No. 1

33--37

One of the economically important species is Penaeus kerathurus (Forskål, 1755), which is widespread in the Mediterranean ecosystem. This paper presents results of research on reproductive biology of Penaeus kerathurus in the Sea of Marmara. A total of 1404 specimens were dissected to determine the maturity stages, reproduction time, and length at first reproduction. The female-to-male ratio was 1:0.9. A high percentage of mature females was determined in April, May and July. Moreover, the value of the gonadosomatic index (GSI) decreased after July. The spawning period was observed between April and July, and its intensity increased in July. The carapace length at first sexual maturity was determined to be 39 mm.

Age, growth and reproductive biology of the saddled seabream (Oblada melanura) in the North Aegean Sea, Eastern Mediterranean

Daban Ismail Burak, Ismen Ali, Ihsanoglu Mukadder Arslan, Cabbar Koray

Oceanological and Hydrobiological Studies

2020

Vol. 49, No. 1

13--22

This study determines the length distribution, length–weight relationship, age, growth parameters, mortality rate, sex ratios, length at first maturity and reproduction of saddled seabream (Oblada melanura) collected monthly by fishermen around the Northern Aegean Sea between November 2017 and October 2018. The length–weight relationship was calculated as W=0.0091×L 3.11 (R 2=0.95) and positive allometric growth was found. The condition factor and GSI varied between 0.81–1.58 and 0.01–9.61, respectively. The spawning season extended from May to July and peaked in June. Total lengths at 50% maturity were 18.97 cm for males and 18.83 cm for females. Parameters of the von Bertalanffy growth equation were: L∞ =29.91 cm, K =0.27 per year, t0=−0.82 year and age varied between 1 and 8. The instantaneous rates of total mortality (Z) and natural mortality (M) were 1.36 and 0.58 per year, respectively. Rates for fishing mortality F and exploitation E were 0.78 and 0.57 per year, respectively. The mean absolute fecundity (F) was 117 075±23 243 oocytes, ranging from 19130 to 470 132.