Reproduction in Australian Pearl Oysters (Lamellibranchia). V. Pinctada fucata (Gould)

1959 ◽  
Vol 10 (1) ◽  
pp. 45 ◽  
Author(s):  
DJ Tranter
Keyword(s):  
Gonad Development ◽  
Pinctada Fucata ◽  
Spawning Season ◽  
Breeding Cycle ◽  
Histological Structure ◽  
Second Phase ◽  
Spawning Period ◽  
Gonad Differentiation ◽  
Mantle Layer ◽  
Spat Settlement

>Pinctacla fucata, in common with P. albina and P. margaritifera, is hermaphrodite. The gonad develops in a series of phases, in which germ cells are formed anew from indifferent "stem cells" which remain after spawning. Each phase is unisexual, but sex may change from phase to phase. There is a tendency towards protandry, but this is less marked than in P. albina. The percentage of individuals in female phase increases until middle life, by which time the sexes are equally common. Both protandric and protogynic sex-changes have been recorded in the field and, on one occasioii, a bisexual, transitional condition was observed in gonad sections. The evidence shows that sex change is not restricted to the wintering period. Primary gonad differentiation begins 2-3 months after spat settlement, and within 6 months sexual maturity is reached. Frequently, there is a second phase of gonad development towards the end of the first year. The typical adult breeding cycle consists of: a period of gonad differentiation from September to November; a spawning period from December to May; and a resting period from June to August. During the spawning season, there are usually two periods of maximum intensity: January-February ("summer spawning") and April-May ("autumn spawning"), the latter being the more consistent of the two. However, lesser spawnings occur outside the major spawning season, and spatfalls have been recorded throughout the year. The macroscopic and histological structure of the gonad is similar to that of P. albina and P. margaritifera. The following points are noted: gonad colour is an unreliable indication of sex; the white mantle layer covering the gonad is predominantly mucoprotein, and is probably concerned with shell secretion ; there are no yolk nuclei visible in the cytoplasm of the oocyte, as in P. margaritifera; activation of the ripe oocyte takes place within the gonad follicles immediately prior to spawning; as in P. albina spawning is frequently incomplete, and phagocytosis plays a major role in the resorption of unspent gonad products; the haploid chromosome number is six.

Reproductive anatomy, gonad development and spawning seasonality of nurseryfish, Kurtus gulliveri (Perciformes:Kurtidae)

2007 ◽  
Vol 55 (4) ◽  
pp. 211 ◽  
Author(s):  
T. M. Berra ◽  
B. Gomelsky ◽  
B. A. Thompson ◽  
D. Wedd
Keyword(s):  
Gonadosomatic Index ◽  
Abdominal Cavity ◽  
Gonad Development ◽  
Body Cavity ◽  
The Body ◽  
Spawning Season ◽  
Egg Mass ◽  
Histological Structure ◽  
Posterior Portion ◽  
Reproductive Anatomy

The nurseryfish, Kurtus gulliveri, of northern Australia, is remarkable for the fact that the males carry the egg mass on a supraoccipital hook on their forehead. Plankton samples of larval nurseryfish indicate a prolonged spawning season (June–November) that more or less corresponds with the dry season in the Northern Territory. The paired, elongate testes are located in the posterior portion of the body cavity suspended by the mesorchium. The gonadosomatic index (GSI) of males was small and highly variable (mean 0.14, range 0.01–0.27) from June to November. The histological structure of testicular lobes showed maturing and mature stages that contained spermatocytes, spermatids, and spermatozoa. The paired, bean-shaped ovaries contained about 5500 oocytes (1176–9783) and were located in the rear of the abdominal cavity. GSI averaged 1.58 (range 0.36–4.48). Ovarian histology revealed primary growth, cortical alveolar oocytes, vitellogenic oocytes, coalesced yolk, and atresia. The occurrence of postovulatory follicles and late vitellogenetic oocytes in the ovaries clearly indicate that nurseryfish females are batch spawners. Maturing testes showed signs of previous spawnings indicating that males are capable of spawning several times throughout the spawning season. We speculate that nurseryfish may spawn in a manner similar to their closest relatives, cardinalfishes (Apogonidae), with eggs carried on the male’s hook instead of orally.

scholarly journals Continuous light delays sexual maturation and increases growth of Atlantic cod (Gadus morhua L.) in sea cages

2006 ◽  
Vol 63 (2) ◽  
pp. 365-375 ◽  
Author(s):  
G.L. Taranger ◽  
L. Aardal ◽  
T. Hansen ◽  
O.S. Kjesbu
Keyword(s):  
Sexual Maturation ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Gonad Development ◽  
Somatic Growth ◽  
Continuous Light ◽  
Reproductive Investment ◽  
Spawning Season ◽  
Commercial Fish ◽  
Spawning Period

Abstract Prevention of early sexual maturation is essential in Atlantic cod (Gadus morhua) farming because maturity results in reduced growth, affects flesh quality, and may lead to increased mortality. In farmed cod, almost 100% of the fish mature at two years of age and often at a size of 1.5–2 kg. Two pilot experiments were conducted with cod in sea cages at a commercial fish farm in western Norway (60°N) to test the effect of additional continuous light (LL) on the timing of sexual maturation and somatic growth compared with controls under natural light (NL). In the NL groups, 100% maturation was indicated during the natural spawning period from February to April at the age of two years. By contrast, LL treatment from 27 June (15-month-old cod) or 2 September (18-month-old cod) onwards delayed gonad development by three to five months, reduced reproductive investment, and enhanced winter growth compared with the controls. Fish held at NL decreased in body weight during the spawning season (February–April), whereas LL-exposed fish appeared to continue to grow during their spawning season (May–August). LL-treated cod reached mean body weights of 2.90–3.13 kg within 28 months of hatching, whereas the controls reached 2.20–2.42 kg during the same period.

scholarly journals Spawning season, recruitment and early life distribution of Anchoa tricolor (Spix and Agassiz, 1829) in a tropical bay in southeastern Brazil

2008 ◽  
Vol 68 (4) ◽  
pp. 823-829 ◽  
Author(s):  
FG. Araújo ◽  
MA. Silva ◽  
MCC. Azevedo ◽  
JNS. Santos
Keyword(s):  
Early Life ◽  
Gonad Development ◽  
Late Summer ◽  
Sandy Beaches ◽  
Reproductive Season ◽  
Southeastern Brazil ◽  
Life Distribution ◽  
Beach Seine ◽  
Spawning Period ◽  
Fishery Resource

The pattern of the use of the Sepetiba Bay, a semi-closed 450 km² area in southeastern Brazil, by Anchoa tricolor was investigated to assess spawning period, recruitment and to detect spatial-temporal patterns of this major fishery resource. Fishes were sampled by seine nets, from spring, 1998 to winter, 1999 and by beach seine, from spring, 1998 to winter, 2000. Reproductive season, measured in terms of GSI, gonad development and appearance of recruits, indicate that reproduction occurs from August to March, when they reach the best condition. Recruitment peaks in winter/spring at sandy beaches where they stay until late summer, moving toward deeper bay areas during autumn. After that, they join adults and perform movements between the bay and the adjacent continental shelf to reproduce.

scholarly journals N-Cadherin Is Critical for the Survival of Germ Cells, the Formation of Steroidogenic Cells, and the Architecture of Developing Mouse Gonads

Cells ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1610 ◽  
Author(s):  
Rafal P. Piprek ◽  
Michal Kolasa ◽  
Dagmara Podkowa ◽  
Malgorzata Kloc ◽  
Jacek Z. Kubiak
Keyword(s):  
Germ Cells ◽  
Hormonal Regulation ◽  
Critical Role ◽  
Somatic Cells ◽  
Gonad Development ◽  
Knock Out ◽  
Gonad Differentiation ◽  
Steroidogenic Cells ◽  
The Individual ◽  
And Function

Normal gonad development assures the fertility of the individual. The properly functioning gonads must contain a sufficient number of the viable germ cells, possess a correct architecture and tissue structure, and assure the proper hormonal regulation. This is achieved by the interplay between the germ cells and different types of somatic cells. N-cadherin coded by the Cdh2 gene plays a critical role in this interplay. To gain an insight into the role of N-cadherin in the development of mouse gonads, we used the Cre-loxP system to knock out N-cadherin separately in two cell lines: the SF1+ somatic cells and the OCT4+ germ cells. We observed that N-cadherin plays a key role in the survival of both female and male germ cells. However, the N-cadherin is not necessary for the differentiation of the Sertoli cells or the initiation of the formation of testis cords or ovigerous cords. In the later stages of gonad development, N-cadherin is important for the maintenance of testis cord structure and is required for the formation of steroidogenic cells. In the ovaries, N-cadherin is necessary for the formation of the ovarian follicles. These results indicate that N-cadherin plays a major role in gonad differentiation, structuralization, and function.

scholarly journals Gonad development and reproductive hormones of invasive silver carp (Hypophthalmichthys molitrix) in the Illinois River

2019 ◽  
Vol 102 (3) ◽  
pp. 647-659
Author(s):  
Emily K Tucker ◽  
Megan E Zurliene ◽  
Cory D Suski ◽  
Romana A Nowak
Keyword(s):  
Silver Carp ◽  
Gonad Development ◽  
Life History Strategy ◽  
High Plasma ◽  
Early Summer ◽  
Reproductive Hormones ◽  
Illinois River ◽  
Plasma Testosterone ◽  
Hypophthalmichthys Molitrix ◽  
Spawning Period

Abstract Reproduction is a major component of an animal’s life history strategy. Species with plasticity in their reproductive biology are likely to be successful as an invasive species, as they can adapt their reproductive effort during various phases of a biological invasion. Silver carp (Hypophthalmicthys molitrix), an invasive cyprinid in North America, display wide variation in reproductive strategies across both their native and introduced ranges, though the specifics of silver carp reproduction in the Illinois River have not been established. We assessed reproductive status using histological and endocrinological methods in silver carp between April and October 2018, with additional histological data from August to October 2017. Here, we show that female silver carp are batch spawners with asynchronous, indeterminate oocyte recruitment, while male silver carp utilize a determinate pattern of spermatogenesis which ceases in the early summer. High plasma testosterone levels in females could be responsible for regulating oocyte development. Our results suggest that silver carp have high spawning activity in the early summer (May–June), but outside of the peak spawning period, female silver carp can maintain spawning-capable status by adjusting rates of gametogenesis and atresia in response to environmental conditions, while males regress their gonads as early as July. The results of this study are compared to reports of silver carp reproduction in other North American rivers as well as in Asia.

Differential postspawning mortality among male and female capelin (Mallotus villosus Müller) in captivity

1998 ◽  
Vol 76 (3) ◽  
pp. 588-592 ◽  
Author(s):  
Margaret PM Burton ◽  
Shawn R Flynn
Keyword(s):  
Spawning Season ◽  
Mallotus Villosus ◽  
Female Fish ◽  
Male Fish ◽  
Spawning Period ◽  
Male And Female ◽  
Progressive Development ◽  
In Captivity ◽  
Capelin Mallotus Villosus ◽  
In The Wild

Male and female capelin (Mallotus villosus Müller) were captured in 1993 at the start of spawning and males were captured in 1995 at the end of the spawning period. All male fish from both years died within 6 weeks of capture. Spent males captured in the wild showed almost empty testes with very few residual sperm and no evidence of developing spermatocytes. All female fish survived the first 6 weeks and over 50% survived 20 weeks. Sampling of the surviving females after 20 weeks showed evidence of prior spawning and progressive development of oocytes for the next summer's spawning season. It was concluded that while males may be semelparous, females are inherently iteroparous.

scholarly journals Biological parameters of Pseudocurimata boulengeri (Characiformes: Curimatidae) inhabiting the Chongón dam, Ecuador

2016 ◽  
Vol 64 (1) ◽  
pp. 131
Author(s):  
David Chicaiza Veloz ◽  
Héctor Flores
Keyword(s):  
Gonad Development ◽  
Biological Data ◽  
Reproductive Season ◽  
Spawning Season ◽  
Male And Female ◽  
Lentic System ◽  
High Production ◽  
First Maturity ◽  
Size At First Maturity ◽  
Production Characteristics

Pseudocurimata boulengeri is an endemic species of Ecuador, which sustains a large group of fisher families. The biological data of this species correspond to reports from lotic systems of Los Ríos province; nevertheless, their trend in a lentic system is not yet known. This paper describes the sex ratio, length-weight relationship, gonad development, spawning season and size at reproductive maturity of P. boulengeri, inhabiting the lentic system of Chongón dam, Ecuador. Fish were caught between 2003 and 2009 using gill nets (2.5"). The total length (Lt) of caught specimens ranged from 10.5 to 35.5 cm, spawning occurred between the months of October and March, and size at first maturity for females was estimated at 17.9 cm (Lt) and 20.0 cm (Lt) for males. Between May and October male and female ratios were as expected (1:1), whereas for May, November and April, females ratios were higher than males, situation that coincided with the spawning season. The limnetic conditions and high production characteristics of Chongón dam, have promoted the availability of a great amount of food for this species, which may have allowed P. boulengeri to have a more extended reproductive season in this favorable environment.

scholarly journals Reproductive biology of silurid catfishes Ompok miostoma (Vaillant 1902) in Mahakam River East Kalimantan

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
. Jusmaldi ◽  
Dedy Duryadi Solihin ◽  
Ridwan Affandi ◽  
MF Rahardjo ◽  
Rudhy Gustiano
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Spawning Season ◽  
Spawning Period ◽  
Male And Female ◽  
Gonad Maturity ◽  
East Kalimantan ◽  
Fish Samples ◽  
Total Fish ◽  
Somatic Index

Reproductive biology of silurid catfish O.miostoma(Vaillant 1902)as one of endemic species in Mahakam River East Kalimantan is not yet known. This study aimed to analysisreproductive aspect related to changing seasons, including sex-ratio, spawning season, spawning location, length at first gonad maturity, gonado-somatic index, and fecundity. Total fish samples (n=1214)were collected monthly from November 2013 to October 2014 at four locations in the Mahakam River, using many fishing gears.The results of this research showthe total length of fish ranged from 132.19 to 227.30 mm and weight ranged from 20.00 to 70.40 g. The overall sex ratio of male and female was1: 1.56, while at gonad maturity stages were1:1.77. The spawning season range from November to January and peak spawning occurs in December. The highest spawning location was found at swamp flood Semayang Lake. The length at first gonad maturity of male ranged of 191.05-202.60 mm, while it was in 179.56-198.50 female. Maximum average gonado-somatic index (GSI) values obtained for male and female were 0.32 and 2.07 respectively during spawning period in November and declined to minimum in February. The total fecundity and eggs diameter rangedfrom 2648 to 12495 eggsind-1and 0.61 to 1.30 mm respectively. There was a positive correlation between fecundity andtotal length and weightof fishes.AbstrakBiologi reproduksi ikan lais O. miostoma (Vaillant 1902)sebagai salah satu spesies endemik di Sungai Mahakam Kalimantan Timur belum pernah diketahui. Tujuan penelitian ini adalah menganalisisaspek reproduksi ikan laisberkaitan dengan perubahan musimyang mencakupnisbah kelamin, musim pemijahan, lokasi pemijahan, ukuran kali pertama matang gonad, indeks kematangan gonad dan fekunditas.Total ikan contoh 1214 ekor telah dikumpulkan setiap bulan mulai dari bulan November 2013 sampai Oktober 2014di empat lokasi perairan Sungai Mahakam, menggunakan berbagai alat tangkap. Hasil penelitian menunjukkanukuran panjang total ikan berkisar dari 132,19-227,30 mm dan bobot berkisar dari  20,00-70,40 gram.Nisbah kelamin seluruh ikan jantan dan betina yang diamati 1 : 1,56, sedangkanpada tahap kematangan gonad 1:1,77. Musim pemijahan terjadi mulai dari bulan November sampai Januari dan puncak pemijahan pada bulan Desember. Lokasi pemijahan tertinggi ditemukan di rawa banjiran Danau Semayang. Ukuran ikan pertamamatang gonad pada jantan berkisar dari 191,05-202,60 mm dan betina berkisar dari 179,56-198,50 mm. Rata-rata indeks kematangan gonad (IKG)  tertinggi ditemukan pada jantan dan  betina berturut turut 0,32  dan 2,07 selama musim pemijahanpada bulan November dan menurun hingga terendah pada bulan Februari. Fekunditas total berkisar dari 2.648-12.495 butir telur per individu.Ada korelasi positif antara fekunditas dengan panjang total dan bobot ikan.

The gametogenic cycle of Scrobicularia plana (Mollusca: Bivalvia) in Mweeloon Bay (Galway, west coast of Ireland)

2006 ◽  
Vol 86 (5) ◽  
pp. 1157-1162 ◽  
Author(s):  
Jean Raleigh ◽  
Brendan F. Keegan
Keyword(s):  
West Coast ◽  
Shell Length ◽  
Developmental Stages ◽  
Gonad Development ◽  
Breeding Cycle ◽  
Gametogenic Cycle ◽  
Broad Agreement ◽  
Northern Latitudes ◽  
Scrobicularia Plana ◽  
Male Sex

The gametogenic cycle of Scrobicularia plana was studied in Mweeloon Bay (Galway, west coast of Ireland) over the periods of February to September 1996 and January to September 1997. Quantitative (reproductive indices and oocytes size) and qualitative (gonad developmental stages) analysis identified a broad annual breeding cycle, with one protracted spawning event occurring from May until September. Early gonad development had begun by January/February. Spawning animals were first recorded at the end of May and continued to mature throughout the summer. The decrease in temperature in September coincided with the end of the spawning season and gonad regression. Although the species is predominantly dioecious, one case of hermaphrodism was recorded. A female to male sex ratio of 1.1:1 was registered. Sexual maturity occurred at a shell length greater than 20 mm; the smallest individual undergoing sexual development had a shell length of 22.4 mm. The timing of the reproductive cycle in S. plana at Mweeloon Bay is in broad agreement with previous findings on the species carried out in northern latitudes.

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