scholarly journals The expression of secondary sexual characteristics in recruit- and repeat-spawning farmed and wild Atlantic cod (Gadus morhua)

2008 ◽  
Vol 65 (9) ◽  
pp. 1710-1716 ◽  
Author(s):  
Jon Egil Skjæraasen ◽  
Justin J. Meager ◽  
Ørjan Karlsen

Abstract Skjæraasen, J. E., Meager, J. J., and Karlsen, Ø. 2008. The expression of secondary sexual characteristics in recruit- and repeat-spawning farmed and wild Atlantic cod (Gadus morhua). – ICES Journal of Marine Science, 65: 1710–1716. We examined the expression of the two known secondary sexual characteristics of Atlantic cod, the pelvic fin and the drumming muscle, in farmed and wild cod stemming from the same population. Farmed and wild males had longer pelvic fins and larger drumming muscles than females, but wild cod had longer fins than farmed cod. The size of the drumming muscle of males was similar among wild and farmed cod, but farmed females had smaller muscles than their wild counterparts. Repeat-spawning wild males tended to invest less in drumming-muscle mass and more in pelvic-fin growth than recruit-spawning fish, whereas the reverse was true for farmed males. Males use pelvic fins to embrace females during ventral mounts, a key mating behaviour, and display them to other males during agonistic interactions. The drumming muscle is used by males to produce sound during courtship and aggressive displays, whereas females only use sound outside the spawning season, for agonistic and defensive behaviours that are unlikely to be as important in the farming environment. The results are discussed in the context of the reproductive success of farmed escapees in the wild.

2014 ◽  
Vol 92 (6) ◽  
pp. 537-543 ◽  
Author(s):  
N. Fabre ◽  
F. Oliva ◽  
E. García-Galea ◽  
D. Vinyoles

Alternative reproductive tactics (ARTs) driven by environmental factors are common among fish. However, the flexibility of fish to adopt distinct tactics in response to the characteristics of their environment has received little attention. The aim of the present work was to study phenotypic plasticity in the adoption of dominant behaviour (“bourgeois tactic”) by male freshwater blennies (Salaria fluviatilis (Asso, 1801)). For this purpose, two simultaneous experiments in aquaria were performed to examine the effect of social cues and nest abundance on the acquisition of secondary sexual characteristics (SSCs). Experiments were conducted with small (individuals without SSCs), medium-sized (1-year-old individuals), and large older dominant males (more than 2 years old), all collected in the wild. In experiment 1, the three sizes of males were combined to compare the development of SSCs depending on intrasexual context. In experiment 2, the effect of nest abundance (two nests vs. six nests) was tested for each size of male. Medium-sized males showed phenotypic plasticity in response to the environmental conditions simulated in the two experiments. The absence of larger dominant males was found to be the main factor enhancing SSCs and the onset of parental behaviour. Nest shortage also influenced the degree of cephalic crest development among medium-sized males. This knowledge helps to understand how the population of freshwater blennies still persists when it is reduced to young individuals during the summer droughts in Mediterranean streams.


1989 ◽  
Vol 67 (4) ◽  
pp. 1053-1060 ◽  
Author(s):  
Bernard Lebeau ◽  
Gérard Pageau

Primary and secondary sexual characteristics in northern pike, Esox lucius Linneaus, and muskellunge, Esox masquinongy Mitchill, differ markedly. Differences in the internal urogenital anatomy include the structure of the genital ducts and the angle they form with the ventral surface. Externally, the genital and urinary ducts open directly to the environment in northern pike, whereas in muskellunge they open into a muscular papilla and then through a urogenital pore. Differences in sexual dimorphism between the two closely related esocids constitute a structural basis to explain the known differences in spawning behaviour and reproductive success. Differences in secondary sexual characteristics explain why the methods developed by Demchenko or Casselman to externally sex pike are inapplicable to muskellunge. To develop and test two external sexing techniques for muskellunge, specimens were collected from two regions in Canada from 1980 to 1987. Examination of reproductive products obtained from stripping provided an accurate indicator of sex and sexual maturity, but demonstrated serious limitations. A simple method to sex muskellunge by examination of the external urogenital morphology is described for juveniles and adults. Dissection of fish revealed that with the urogenital examination technique we sexed juveniles with a success rate of 92–98%, and adults with 100% accuracy.


2015 ◽  
Vol 218 (7) ◽  
pp. 603-615 ◽  
Author(s):  
Jia-Woei Hou ◽  
Ching-Ling Lin ◽  
Yen-An Tsai ◽  
Chia-Huang Chang ◽  
Kai-Wei Liao ◽  
...  

2021 ◽  
pp. 113-118
Author(s):  
V. A. Melnik

Objective: to assess the constitutional features of the age dynamics of secondary sexual characteristics and functional parameters of city schoolchildren in the age range of 7–17 years.Materials and methods. The objects of the study were schoolchildren aged 7–17. The stages of the expression of secondary sexual characteristics were determined visually according to the scheme by J.M. Tanner. The functional parameters of the examined schoolchildren were assessed using the methods of dynamometry, spirometry; blood pressure and heart rates, as well as the time of simple sensorimotor reactions were measured.Results. As a result of the performed studies, it has been found that representatives of the hypersomnic types are ahead of other types to reveal the first stages of secondary sexual characteristics. Schoolchildren with the leptosomic morphotypes due to higher rates of their development have reached the definitive stages by the same age as those with the hypersomnic variants. The intensity of age-related changes in functional parameters (strength qualities, circulatory and respiratory systems, nervous system) in the studied objects depends on their body type.Conclusion. The stage and rate of puberty, as well as the development of functional parameters in city schoolchildren depends on their somatotype.


2019 ◽  
Vol 7 (1) ◽  
pp. 6
Author(s):  
Shu-Heng Huang ◽  
Daw-Yang Hwang ◽  
Shang-Jyh Hwang

17α-hydroxylase deficiency (17OHD) is a rare disorder of secondary hypertension caused by congenital adrenal hyperplasia. In addition, co-occurrence of an adrenal tumor with 17OHD is extremely rare and easily misdiagnosed. A 33-year-old female with sicca syndrome, persistent hypertension, hypokalemia, and a left adrenal tumor was referred for confirmation of primary aldosteronism. However, the absence of secondary sexual characteristics, persistent growth beyond puberty, and laboratory data of low plasma renin activity, high aldosterone, low cortisol, low sex hormones, elevated adrenocorticotropic hormone, elevated luteinizing hormone, elevated follicle-stimulating hormone, and most importantly, decreased 17-hydroxypregnenolone, supported a diagnosis of 17OHD. We sequenced the CYP17A1 gene of the patient and her parents, which demonstrated genetic defects (D487-S,488-F489 deletion and Y329K418X). 17OHD was diagnosed. The left adrenal tumor was assessed, and a non-functional adrenal incidentaloma was confirmed; NP-59 adrenal cortical scintigraphy and adrenal venous sampling showed no functional activity and non-lateralization. Hormone replacements with estrogen, spironolactone, and prednisolone were given. The patient became more feminized and confident, and her hypertension was controlled. Early diagnosis and treatment of 17OHD not only can prevent delay development of secondary sexual characteristics but also help the patient maintain mental health and improve their quality of life. In addition, the concomitant presence of a left adrenal tumor makes misdiagnosis of a functional adenoma more likely, possibly causing unnecessary surgery and delay inappropriate treatment.


Author(s):  
Nidhi Jain ◽  
Jyotsna Harlalka Kamra

Primary amenorrhea is defined as failure to achieve menarche till age of 14 years in absence of normal secondary sexual characters or till 16 years irrespective of secondary sexual characters. The most common cause of primary amenorrhea is gonadal pathology followed by Mayer-Rokitansky-Küster-Hauser syndrome (MRKH syndrome). MRKH syndrome is a rare congenital disorder characterised by uterine and vaginal aplasia. It occurs due to failure of development of Müllerian duct. Its incidence is 1 per 4500 female births. Mostly girls present with primary amenorrhea. It is characterised by presence of normal secondary sexual characteristics, normal 46 XX genotype, normal ovarian function in most of the cases and absent or underdeveloped uterus and upper part (2/3) of vagina. It is of two types: type A is isolated type while type B is associated with other renal/skeletal/cardiac anomalies. Treatment includes psychological counselling and vaginoplasty. Vaginoplasty can be done by various non-surgical and surgical techniques. The authors hereby review the literature of MRKH syndrome regarding its embryology, etiopathogenesis, approach to work up and management.


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