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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.

Differences in the maturation level among life histories of the Japanese eel Anguilla japonica in the Nagata River, Japan

Chino N., Imai C., Sakai H., Arai T.

Oceanological and Hydrobiological Studies

2017

Vol. 46, No. 4

472--477

In order to understand the silver eel migration behavior of the Japanese eel Anguilla japonica, the life history of both the yellow stage (immature stage) and the silver stage (early maturing stage) was examined during the silver eel migration period, using otolith microchemical analysis of strontium (Sr) and calcium (Ca) concentrations. The mean Sr:Ca ratios in A. japonica from the elver mark to the otolith edge indicate eels of several general categories of migratory histories, including sea eels (average Sr:Ca ratios, ≥ 6.0 × 10-3), estuarine eels (average Sr:Ca ratios, 2.0 × 10-3 ≤ Sr:Ca < 6.0 × 10-3) and river eels (average Sr:Ca ratios, < 2.0 × 10-3), based on the criteria reported previously in A. japonica. A significant negative correlation was observed between the gonadosomatic index (GSI) and the mean Sr:Ca ratios during the growth phase after recruitment. Gonads of river eels were more developed compared to eels with other migratory histories. It thus appears that the maturation level for the silver eel migration to the open ocean varies depending on the life history.

Breeding characteristics of the sand goby (Pomatoschistus minutus) - one of the most abundant goby species in the costal waters of the Gulf of Gdańsk region (southern Baltic Sea)

Waligóra-Borek K., Sapota M. R.

Oceanological and Hydrobiological Studies

2005

Vol. 34, No.4

47--55

The reproduction aspect of the biology of Pomatoschistus minutus was investigated on fish collected in the Gulf of Gdańsk from March to October 2002. The study zone was from the shore to a depth of about 1 m. The sand goby is common in the investigated area from July to October, but it migrates to deeper water in the colder months. The highest numbers of individuals were observed in September. The spawning season of the sand goby in the Gulf of Gdańsk is from April to August. It is so long because this species is batch spawner. The study confirmed a dependence between the HSI and GSI indexes as well as the dependence between relative fecundity and fish length.