Control of Gonadal Maturation and Regression by Experimental Variation of Environmental Factors in the Mormyrid Fish, Mormyrus rume proboscirostris

Schugardt, Christian; Kirschbaum, Frank

doi:10.1023/b:ebfi.0000033340.49266.f3

Cited by 25 publications

(22 citation statements)

References 14 publications

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“…Recent data obtained in the grass carp, Ctenopharyngodon idella, introduced in a tropical area, suggest that several relays along the brain-pituitarygonad axis may be simultaneously deregulated [59]. Apart from temperature, other physico-chemical factors can also play a role, especially in euryhaline migrating species, such as hydrostatic pressure associated with depth in the European anguilla Anguilla anguilla [60], water salinity changes in the Atlantic salmon Salmo salar, or water electric conductivity changes in mormyrids [61]. Finally, social factors, i.e.…”

Section: Importance Of Environmental Factorsmentioning

confidence: 99%

Particularities of reproduction and oogenesis in teleost fish compared to mammals

2005

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-Compared to mammals, teleost reproduction presents many original features. Reproductive strategies of species are diversified into numerous adaptations to a large variety of aquatic environments. This diversity may concern sexuality, spawning and parental behaviour, sensitivity to environmental factors, and specific features of gametogenesis such as the duration of vitellogenesis, and egg morphology. Sexuality presents a variety of natural modalities, from gonochorism to hermaphrodism. The absence of definitive arrest of body growth in the adult of most species gives a particular interest to the practical control of growth-reproduction interactions. Vitellogenesis, which represents an important metabolic effort for the maternal organism, involves the synthesis of vitellogenin, a specific glycolipo-phosphoprotein produced in the liver under estradiol stimulation, and its incorporation into oocytes by a receptor mediated process. Both estradiol synthesis in follicle cells and vtg uptake by vitellogenic follicles appear to be mainly controlled by FSH. Oocyte maturation is directly triggered by a progestin, or MIS (maturation inducing steroid) synthesised in follicle cells mainly under LH control, and acting through the non-genomic activation of a membrane receptor. Practical applications of some of these particularities result mainly from the external character of the fertilisation process and of embryonic development, which allows manipulating respectively egg chromosome stocks and sex differentiation. Moreover, the sensitivity of sex differentiation to exogenous factors favours the development of practical methods to control the sex of farmed populations. Finally, the sensitivity of reproductive mechanisms to xenobiotics has led to various kinds of bioassays for putative pollutants.reproductive strategies / sexuality / spawning / vitellogenesis / oocyte maturation / fertilisation

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Section: Importance Of Environmental Factorsmentioning

confidence: 99%

Particularities of reproduction and oogenesis in teleost fish compared to mammals

2005

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“…Azadi et al (1995) already demonstrated that the ovary of caught N. notopterus was filled with four different stages (I to IV) of oocytes. Among a multitude of teleostean groups with this style of egg development and deposition, fractional spawning was also observed in Pollimyrus isidori (Kirschbaum 1987, Kirschbaum and Schugardt 1995, 2002, in Mormyrus rume probocirostris (Schugardt and Kirschbaum 2004), in fishes of the Paramormyrops magnostipes-complex (Nguyen 2011), and in Xenomystus nigri (Nyonje 2006).…”

Section: Discussionmentioning

confidence: 93%

“…Variation of environmental parameters to induce the gonad maturation was stimulated with the method developed by Schugardt and Kirschbaum (2004), namely through manipulation of the conductivity of the water. Continuous decreasing conductivity was achieved by adding demineralized water to the water in the experimental tanks.…”

Section: Methodsmentioning

confidence: 99%

Reproduction and development of the asian bronze featherback Notopterus notopterus (Pallas, 1769) (Osteoglossiformes, Notopteridae) in captivity

Yanwirsal¹,

Bärtsch²,

Kirschbaum³

2017

ZSE

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Experimental data demonstrate that the environmental factors decreasing conductivity, slight variation of temperature, and water level have no influence on gonad development or courtship behavior in Notopterus notopterus. Spawning occurs during day time at a temperature of 25-28 °C. Newly spawned 3.8-4 mm adhesive eggs are guarded by the male until hatching. The egg envelope has external spiraling ridges, which are centered round the micropyle. Hatching occurs within 168-204 hours depending on temperature and even with some variability at 27°C constant incubation temperature. Exogenous feeding then starts on day 17 with a total length of 16.2 mm and yolk-sac remnants still present. The larval period lasts until day 36. Dark brown stripes appear on the body as one of the characteristic pigment patterns of juvenile N. notopterus at day 70 with a total length of around 34 mm, replacing the dotted pigment pattern of larvae and early juveniles. Later again a spectacular color change to uniformly gold-bronze coloration occurs. The genital papilla can macroscopically be recognized at day 80. Sexual maturity of N. notopterus in captivity as indicated by courtship behavior is first observed in 30-month old specimens of both sexes of the F1 generation with a total length of around 275 mm in males and 230 mm in females, whereas this might occur at smaller size in the P generation and in natural environment. Generally, in N. notopterus the embryonic period lasts longer and the onset of the larval period starts much delayed as compared to a typical indirect or saltatory development. The larval period before onset of the juvenile period with its spectacular color changes, shows few discernible stages of morphological development. It is immediately a pterygiolarva with the jaws, branchial arches, most fins differentiated, a distinct pigmentation pattern and the mouth opened during the embryonic and free embryonic phases. Key WordsBreeding in captivity reproductive behavior ontogeny Osteoglossomorpha

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“…Although no information is available about the breeding season for B. brachyistius, other mormyrids breed with the onset of the rainy seasons (Hopkins and Bass, 1981;Kirschbaum, 1995). Decreasing water conductivity, increasing water levels, and artificial rainfall on the surface all promote gonad growth in this and other species (Kirschbaum, 1979;Kirschbaum, 1987;Kirschbaum and Schugardt, 2002;Schugardt and Kirschbaum, 2004). The fish used in this study were wild-caught sexually mature males (N=4) and females (N=4) with a standard length greater than 110·mm.…”

Section: Methodsmentioning

confidence: 99%

Electrical and behavioral courtship displays in the mormyrid fish Brienomyrus brachyistius

Wong

Hopkins

2007

Journal of Experimental Biology

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SUMMARY Mormyrid electric fish rely on the waveform of their electric organ discharges (EODs) for communicating species, sex, and social status, while they use the sequences of pulse intervals (SPIs) for communicating rapidly changing behavioral states and motivation. Little is known of electric signaling during courtship behavior because of two major difficulties: (1) the fish are not easily bred in captivity and (2) there is no reliable means of separating electric signals from several individuals in natural communication settings. Through simulating artificial rain conditions, we have successfully induced courtship and succeeded in breeding a mormyrid electric fish(Brienomyrus brachyistius) in the laboratory. We have also developed a system of video recording and editing combined with cross correlation analysis to precisely record and view behavior and separate EODs from two individuals in non-breeding and breeding contexts. Knowing the electrical and motor patterns during courtship allows for further exploration of topics such as mate choice and neural basis of pattern generation in these fish. Here we describe nine common motor displays and 11 SPIs. Analysis of frequency of occurrences suggests that some SPI patterns are sex and season specific. We also observed electrical duetting called `rasp matching' during courtship signaling among pairs; males and females exchange `rasps' and`bursts', respectively, in alternation. Our study employs new techniques to separate and document SPIs in the context of courtship. We show that some SPIs correlate with specific behavioral acts around the time of spawning.

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Control of Gonadal Maturation and Regression by Experimental Variation of Environmental Factors in the Mormyrid Fish, Mormyrus rume proboscirostris

Cited by 25 publications

References 14 publications

Particularities of reproduction and oogenesis in teleost fish compared to mammals

Particularities of reproduction and oogenesis in teleost fish compared to mammals

Reproduction and development of the asian bronze featherback Notopterus notopterus (Pallas, 1769) (Osteoglossiformes, Notopteridae) in captivity

Electrical and behavioral courtship displays in the mormyrid fish Brienomyrus brachyistius

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