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1

The fecundity and gonad development cycle of the round goby (Neogobius melanostomus Pallas 1811) from the Gulf of Gdańsk

100%

Tomczak M. T. , Sapota M. R.

Oceanological and Hydrobiological Studies

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2006

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tom Vol. 35, No.4

353-367

EN

The round goby (Neogobius melanostomus Pallas 1811) is a non-native species in the Gulf of Gdańsk. The aim of this article is to assess the absolute fecundity and attempt to describe the gonad development cycle of round goby specimens from the Gulf of Gdańsk. The stages of gonad development were classified according to the modified Nikolski (1963) scale for perciformes, which was adapted for the round goby. The sex ratio (female to male) in the population was 3:5. Spawning was most intense during April and July, and there was a pause in June. Fish body size determined fecundity.

2

Reproductive biology of the rayed pearl oyster (Pinctada imbricata radiata, Leach 1814) in Izmir Bay

88%

Yigitkurt S.

Oceanological and Hydrobiological Studies

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2021

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tom Vol. 50, No. 1

87--97

EN

The present study was carried out to determine gonadal stages and quality of pearl oyster meat (Pinctada imbricata radiata, Leach, 1814) in Izmir Bay (Turkey). Pearl oyster samples were collected from the study area at a depth of ~5 m between February 2013 and January 2014. The highest and lowest temperature was measured in July and January as 27°C and 14.2°C, respectively. The maximum chlorophyll a value of 4.640 µg l−1 was calculated in May and the lowest value of 1.009 µg l−1 was recorded in April. Individuals reached their first maturity in April. Spawning activity was observed from June to September and the gonad index (GI) was at the highest level during those months. The development was observed from April to February. The overall female to male ratio was 1.32:1 (p < 0.05) and it did not affect the GI (p > 0.05). There is a strong positive correlation between the GI and temperature (p < 0.05). The highest condition index (CI) was recorded in May as 12.31 ± 0.51, whereas the lowest one in January as 7.37 ± 0.22. As a result, this study revealed that the pearl oyster population in the region is characterized by high reproductive activity, especially during the summer months.

3

Gonadal development of allotriploid Cobitis females (Pisces, Cobitidae)

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Juchno D. , Boron A. , Kujawa R.

Acta Biologica Cracoviensia. Series Botanica. Supplement

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2008

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tom 50

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nr 1

4

The fecundity and gonad development cycle of the round goby [Neogobius melanostomus Pallas 1811] from the Gulf of Gdansk

75%

Tomczak M. T. , Sapota M. R.

Oceanological and Hydrobiological Studies

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2006

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tom 35

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nr 4

5

Histological analysis of the annual cycle of gonad development in the male spin-cheek crayfish Orconectes limosus Raf.

63%

Chybowski L. , Juchno D.

Archives of Polish Fisheries

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2002

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tom 10

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nr 2

EN

Histological analyses were conducted of the annual cycle of male gonads of spiny-cheek crayfish Orconectes limosus Raf. Although changes in the male gonads throughout the year are clearly evident, they are not uniform in all males. Spiny-cheek crayfish mate mainly in the autumn from September to November. After mating, the gonads of male crayfish can be divided into two groups according to their histological structure. In the first group there is an abundance of sperm in the gonads, while the testicular tubules in the second group are either empty or contain a small amount of sperm. This division remains until May. In May, the histological picture of the gonads is uniform, and there are either very few or no tubules containing sperm. In June O. limosus males occur in two forms. The histological pictures of first- and second-form male gonads do not differ. However, beginning in July and also in August and September, the gonads of first- and second-form males do differ. First-form male crayfish gonads contain more sperm than those of second-form males. From October onwards, all of the males are first-form, and primarily spermatids and sperm are visible in the gonads. The possibility that the spiny-cheek crayfish mates twice annually, once in autumn and again in spring, is discussed based on changes observed in the histological picture of the gonads.

PL

Gonady samców raka O. limosus pobierano w comiesięcznych odstępach, od września 1999 do sierpnia 2000 roku. Celem pracy było zaobserwowanie zmian zachodzących w obrazie histologicznym gonad raka O. limosus w cyklu rocznym. Dojrzałe płciowo samce raka pręgowatego (Orconectes limosus Raf.) w ciągu roku występują w dwóch formach, różniących się wyglądem odnóży kopulacyjnych (I para odnóży odwłokowych). Forma I umożliwia samcowi przeniesienie nasienia do woreczka nasiennego samicy podczas parzenia się. Natomiast budowa odnóży w formie II uniemożliwia przeniesienie nasienia. Dojrzałe płciowo samce raka O. limosus występują w II formie latem, po wiosennej wylince (od maja - czerwca do sierpnia - września). We wrześniu obraz histologiczny gonad tych dwóch form samców różnił się. Gonada samców występujących w I formie wypełniona była przede wszystkim późnymi stadiami spermatogenezy: spermatydami i plemnikami (fot. 3), natomiast gonada samców występujących w II formie wypełniona była wczesnymi stadiami spermatogenezy: spermatogoniami i spermatocytami (fot. 2). W czerwcu kanaliki gonady I jak i II formy samców wypełnione były jedynie wczesnymi stadiami spermatogenezy (fot. 9). Na podstawie analizy histologicznej gonad spróbowano odpowiedzieć na pytanie czy rak pręgowaty może parzyć się także wiosną. Wiadomo, że rak O. limosus, podobnie jak inne gatunki raków występujących w Polsce parzy się jesienią. Z przeanalizowanego materiału wynika, że u części samców, wiosną, w kanalikach gonady pozostaje jeszcze sporo plemników (fot. 7). Te osobniki mogły przystąpić do wiosennego parzenia się. W drugiej grupie samców gonada zawierała jedynie wczesne stadia spermatogenezy (fot. 6), co zdecydowanie wyklucza możliwość przekazywania nasienia samicy.

6

Stage of gonadal development of cultured salmon [Salmo salar L.] during their second year of life

63%

Domagala J. , Dziewulska K.

Acta Scientiarum Polonorum. Piscaria

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2003

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tom 02

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nr 1

7

Gonad development and reproduction in the monoecious species Chlorophthalmus agassizi (Actinopterygii: Aulopiformes: Chlorophthalmidae) from the Sardinian waters (central-western Mediterranean)

51%

Cabiddu S. , Follesa M. C. , Porcu C. , Cau A.

Acta Ichthyologica et Piscatoria

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2010

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tom 40

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nr 2

EN

Background. The shortnose greeneye, Chlorophthalmus agassizi Bonaparte, 1840, is a species with a circumglobal distribution and is among the most abundant commercial fishes in some Mediterranean areas. The knowledge of the biology and ecology of this species is poor and geographically limited, then the aim of this study is to provide a contribution to the knowledge on the reproductive biology of this monoecious deep-sea fish in Sardinian waters. Materials and Methods. In this paper the morphology and the development of the gonads, the mean size at maturity, the monthly evolution in the percent frequency of the maturity stages, and of the indices related to reproduction of the shortnose greeneye were examined. Individuals were caught by trawls, between 270 and 504 m of depth in the Sardinian seas. Results. The ovarian pattern is of an asynchronous type, characterized by releasing of eggs in successive batches. Seven stages of development for the ovary and four for the testis were identified on the basis of macroscopic and histological features. The female portion is the most evident component and shows a later maturation than the male portion. The spawning period is unique and takes place from May to September. Conclusion. The identification of spawning period and the adopted reproductive strategy is essential to obtain a better understanding of its biology and a good management of its fisheries.

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Biological characteristics of rock goby, Gobius paganellus [Actinopterygii: Perciformes: Gobiidae], in the south-eastern Black Sea

51%

Engin S. , Seyhan K.

Acta Ichthyologica et Piscatoria

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2009

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tom 39

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nr 2

111-118

EN

Background. Gobius paganellus L. is one of the most common gobiid fish in the south-eastern Black Sea. The aim of present study is to provide information on age structure and growth, length at sexual maturity, annual cycle of gonad development, and diet of rock goby in the south-eastern Black Sea. Materials and Methods. One hundred seventy-five specimens of G. paganellus were sampled from two stations in the province of Rize, south-eastern Black Sea. Samplings were performed by free diving using spear gun and hand net at night time. Specimens were dissected and sagittal otoliths, stomachs, livers, and gonads were removed. Otoliths were cleaned, immersed in glycerol, and examined on black background using reflected light at low magnification to determine age. Mean size at sexual maturity (L50) (i.e., size at which 50% of fish are mature) was estimated for males and females by fitting the logistic Gompertz function to the proportion of mature fish per cm size-class. The gonadosomatic index, seminal vesicle somatic index, and hepatosomatic index were calculated on monthly basis. The quantitative importance of different prey in the diet was assessed by calculating the frequency of occurrence, the percentage number, and the percentage mass of prey. The main food index (IMF) was calculated to combine the three used methods (IMF = (0.5 (%F + %N) %W)0.5). Results. The maximum age was estimated to be 7 and 6 years for males and females, respectively. The von Bertalanffy growth parameters was estimated from the mean age-length data for males and females (males: L∞ = 13.1 cm, k = 0.34, to= –0.11; females: L∞ = 18.2 cm, k = 0.18, to= –0.07). The estimated length at sexual maturity was 5.20 and 5.50 cm for males and females, respectively. The spawning season was between March and May. Total fecundity ranged from 1550 to 5839 eggs/female, with an average of 4322 ± 1109 eggs per female. The rock goby feeds on a wide variety of prey items, particularly on gammarids, brachyurans, natantians, bivalves, isopods, and fish. Conclusion. Growth rate (K) and growth performance index (φ’), length at sexual maturity, fecundity and feeding habits of Black Sea rock goby differ from Atlantic populations.