Seasonal changes in gonad maturity, and abundance of larvae and early juveniles of barramundi, Lates calcarifer (Bloch), in Van Diemen Gulf and the Gulf of Carpentaria

1985 ◽  
Vol 36 (2) ◽  
pp. 177 ◽  
Author(s):  
TLO Davis
Keyword(s):  
Breeding Season ◽  
Summer Monsoon ◽  
Seasonal Changes ◽  
Lates Calcarifer ◽  
Spawning Grounds ◽  
Gonad Maturity ◽  
Nursery Areas ◽  
Total Length ◽  
Tidal Pools ◽  
River Mouths

L. calcarifer undergoes a prolonged breeding season that starts just before the summer monsoon. In Van Diemen Gulf the fish spawned in 1978-1979 from September to February, and in the Gulf of Carpentaria in 1979-1980 from November to March. Spawning was localized, occurring near river mouths on coastal mudflats or upstream in rivers where salinities were relatively high (30). There was no evidence for coastal migrations to specific spawning grounds. Juveniles from 9 mm total length entered, on the high spring tides, supralittoral habitats such as tidal pools, gutters, swamps and low- lying inundated coastal floodplain for use as nursery areas.

Maturation and Spawning of Atlantic Herring (Clupea harengus harengus) in the Southern Gulf of St. Lawrence

1975 ◽  
Vol 32 (1) ◽  
pp. 66-68 ◽  
Author(s):  
S. N. Messieh
Keyword(s):  
Clupea Harengus ◽  
Atlantic Herring ◽  
Spawning Grounds ◽  
Nursery Areas ◽  
Maturity Stages ◽  
Clupea Harengus Harengus

Analysis of maturity stages of herring samples taken from the southern Gulf of St. Lawrence shows two maturation cycles for spring and autumn spawning herring. The spring population has a spawning peak in May and the summer–autumn population extends spawning from July through September. Spawning grounds of spring and autumn herring populations and their nursery areas are mapped.

scholarly journals Testicular expression of NGF, TrkA and p75 during seasonal spermatogenesis of the wild ground squirrel (Citellus dauricus Brandt)

2015 ◽  
Vol 59 (3) ◽  
Author(s):  
H. Zhang ◽  
Y. Wang ◽  
J. Zhang ◽  
L. Wang ◽  
Q. Li ◽  
...  
Keyword(s):  
Breeding Season ◽  
Sertoli Cells ◽  
Seasonal Changes ◽  
Ground Squirrel ◽  
Leydig Cells ◽  
Testicular Function ◽  
Nonbreeding Season ◽  
Function Change ◽  
The Mean ◽  
Neuronal Systems

The nerve growth factor (NGF) not only has an essential effect on the nervous system, but also plays an important role in a variety of non-neuronal systems, such as the reproductive system. The aim of this study was to investigate the seasonal changes in<strong> </strong>expression of NGF and its receptors (TrkA and p75) in testes of the wild ground squirrel during the breeding and nonbreeding seasons.<strong> </strong>Immunolocalization for NGF was detected mainly in Leydig cells and Sertoli cells in testes of the breeding and nonbreeding seasons. The immunoreactivity of TrkA was highest in the elongated spermatids, whereas p75 in spermatogonia and spermatocytes in testes of the breeding season. In the nonbreeding season testes, TrkA showed positive immunostainings in Leydig cells, spermatogonia and primary spermatocytes, while p75 showed positive signals in spermatogonia and primary spermatocytes. Consistent with the immunohistochemical results, the mean mRNA and protein level of NGF and TrkA were higher in the testes of the breeding season, and then decreased to a relatively low level in the nonbreeding season. In addition, the concentration of plasma gonadotropins and testosterone were assayed by radioimmunoassay (RIA), and the results showed a significant seasonal change between the breeding and nonbreeding seasons. To conclude, these results of this study provide the first evidence on the potential involvement of NGF and its receptor, TrkA and p75 in the seasonal spermatogenesis and testicular function change of the wild ground squirrel.

Oestrous activity in three subtropical sheep breeds in Upper Egypt and response to long-day light treatment

1991 ◽  
Vol 116 (1) ◽  
pp. 139-143 ◽  
Author(s):  
A. M. Aboul-Naga ◽  
H. Mansour ◽  
M. B. Aboul-Ela ◽  
M. T. Mousa ◽  
Ferial Hassan ◽  
...  
Keyword(s):  
Breeding Season ◽  
Seasonal Changes ◽  
Nile Delta ◽  
Reproductive Activity ◽  
Light Treatment ◽  
Continuous Exposure ◽  
Upper Egypt ◽  
Sheep Breeds ◽  
Awassi Sheep ◽  
Long Day

SUMMARYOestrous activity in local Rahmani and Ossimi sheep and imported subtropical Awassi sheep at different times of the year in Upper Egypt and the effect of continuous exposure to long-day conditions from July till December on this activity was studied in 1986. The three breeds differed substantially in oestrous activity but differences did not seem to be directly related to latitude of origin. Rahmani ewes from the Nile Delta were mostly cyclic all year round; the percentage coming to oestrus each month never fell below 70%. Ossimi ewes originating from mid-Egypt had a very long breeding season; 74% had an anoestrous period of 68·8 days (v. 27% for Rahmani ewes). All Awassi ewes, except one, had an anoestrous period of 96·5 days on average.Awassi ewes also showed more response to continuous exposure to long days (14 h) than Ossimi ewes, seen in a shorter reaction interval and a greater decrease in the percentage of ewes coming into oestrus (27 and 90% in control and treated Awassi ewes, respectively). The results indicated that changes in daylength, although small in subtropical regions, may be a major factor controlling seasonal changes in reproductive activity in subtropical sheep breeds, the more seasonal breed being more responsive to changes in daylength. The possibility of selection within these breeds for continuous reproductive activity is also indicated.

The effect of daylength and nutrition on the oestrous and ovulatory activity of Greyface ewes

1974 ◽  
Vol 18 (2) ◽  
pp. 159-167 ◽  
Author(s):  
M. J. Ducker ◽  
J. S. Boyd
Keyword(s):  
Breeding Season ◽  
Seasonal Changes ◽  
Ovulation Rate ◽  
Abrupt Decrease ◽  
Repeated Observations ◽  
The Mean ◽  
Natural Breeding

SUMMARYThe onset and duration of oestrous and ovulatory activity in 26 Greyface ewes receiving natural daylength changes were determined. Precise ovulation data were obtained by endoscopy and repeated observations of the ovaries of all ewes were made on 10 occasions from 15 July 1971 to 27 June 1972. The natural breeding season for these Greyface ewes was, on average, 22 September 1971 to 18 February 1972. There were significant seasonal changes in the mean ovulation rate of the ewes which appeared to be inversely related to seasonal changes in natural daylength.An abrupt decrease in artificial daylength of 11 -43 hr applied on 22 June 1971 to 28 similar Greyface ewes advanced their mean onset of oestrous activity by 23 days. The decrease in artificial daylength also advanced the occurrence of ovulation in these ewes. The highest mean ovulation rate of the ewes receiving the decrease in artificial daylength was at least as high as the peak mean ovulation rate measured in the control ewes.At most stages of the experiment, the plane of nutrition had no significant effect on either oestrous or ovulatory activity in the ewes.

A comparison of the seasonal hormone changes and patterns of growth, voluntary food intake and reproduction in juvenile and adult red deer (Cervus elaphus) and Père David's deer (Elaphurus davidianus) hinds

1989 ◽  
Vol 122 (3) ◽  
pp. 733-745 ◽  
Author(s):  
A. S. I. Loudon ◽  
J. A. Milne ◽  
J. D. Curlewis ◽  
A. S. McNeilly
Keyword(s):  
Food Intake ◽  
Breeding Season ◽  
Seasonal Changes ◽  
Red Deer ◽  
Species Differences ◽  
Energy Utilization ◽  
Significant Advance ◽  
Plasma Prolactin ◽  
Père David’S Deer ◽  
Voluntary Food Intake

ABSTRACT Non-domesticated seasonally breeding ungulates exhibit marked seasonal changes in metabolic rate, voluntary food intake (VFI), pelage growth and moult and hormone secretion. It is not known whether these seasonal rhythms are regulated by the same central processes which control the onset and termination of the breeding season. Here we compare two closely related deer species which have significantly different mating and calving seasons. Seasonal changes in VFI, liveweight, coat growth, plasma prolactin and tri-iodothyronine (T3), and the timing of the breeding season were examined over a 15-month period in six adult post-pubertal red and Père David's deer from January to April the following year. The timing of the seasonal changes in prolactin, T3, VFI and coat growth were all significantly advanced by 56, 23, 60 and 54 days respectively in the Père David's deer. The times of onset and termination of the breeding season of Père David's deer were also significantly advanced by 90 days, but in both species, the breeding season was of similar duration (160 ± 5 (s.e.m.) days). Changes in liveweight of adult red deer could be explained by changes in VFI rather than efficiency of utilization. This was not the case in Père David's deer and may indicate seasonal changes in the efficiency of energy utilization. In order to establish whether these species differences develop with age, we undertook a second study in which seasonal changes in VFI, growth, plasma prolactin concentrations and the timing of the onset of the breeding season were recorded for ten red deer and six Père David's deer from 6 to 18 months of age. Both species exhibited a similar decline in VFI in the first autumn of life. Subsequently, the Père David's deer exhibited an advance in the timing of the seasonal peak in VFI and prolactin (21 and 66 days respectively); puberty occurred 3 months earlier than in red deer. The earlier breeding season of the Père David's deer was associated with a significant advance in a range of seasonal endocrine and physiological parameters. These species differences may develop with age. Our data indicate that seasonal patterns of metabolism and growth may be closely linked to those mechanisms which also regulate the onset and termination of the breeding season. Journal of Endocrinology (1989) 122, 733–745

scholarly journals Seasonal expressions of androgen receptor, estrogen receptors and cytochrome P450 aromatase in the uteri of the wild Daurian ground squirrels (Spermophilus dauricus)

2018 ◽  
Author(s):  
Yu Wang ◽  
Ziyi Wang ◽  
Wenyang Yu ◽  
Xia Sheng ◽  
Haolin Zhang ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Androgen Receptor ◽  
Breeding Season ◽  
Stromal Cells ◽  
Seasonal Changes ◽  
Ground Squirrels ◽  
Sex Steroid ◽  
Expression Levels ◽  
Cytochrome P450 Aromatase ◽  
Glandular Cells

The reproductive tissues including the uterus undergo dramatic changes in seasonal breeders from the breeding to non-breeding seasons. Classically, sex steroid hormones play important roles in the uterine morphology and functions. To clarify the relationship between sex steroid hormones and seasonal changes in the uterine morphology and functions, the wild Daurian ground squirrels (Spermophilus dauricus) were used as seasonal breeder model. And the immunolocalizations and expression levels of androgen receptor (AR), estrogen receptors α and β (ERα and ERβ) and cytochrome P450 aromatase (P450arom) were investigated in the uteri of the wild Daurian ground squirrels in the breeding (April) and the non-breeding (June) seasons via immunohistochemistry, Western blot and RT-PCR. Histologically, the uterine weight, the thickness of endometrium and the glandular density were significantly higher in the uteri of the breeding season than those of the non-breeding season. In both seasons, the immunostaining of AR was only presented in stromal cells of the uteri; the positive staining of ERα and ERβ were localized in stromal cells and glandular cells; P450arom was merely immunolocalized in glandular cells. The protein and mRNA expression levels of ERα, ERβ and P450arom were higher in the uteri of the breeding season than those of the non-breeding season; conversely, the expressions of AR were higher in the uteri of the non-breeding season comparing with those of the breeding season in both protein and mRNA levels. The AR: ER ratio in the uteri of the non-breeding season exceeded the AR: ER ratio in the uteri of the breeding season in the wild Daurian ground squirrels. These results suggested that seasonal changes in the expression levels of AR, ERs and P450arom might be correlated with the uterine morphology and histology changes, and estrogen may play an important autocrine/paracrine role in regulating the uterine functions of the wild Daurian ground squirrels.

scholarly journals Evaluation of Fish Meals as Natural Feed Stimulants on the Feeding Behaviour of Fry and Juveniles of Lates calcarifer (Bloch)

2006 ◽  
Vol 19 (2) ◽  
Author(s):  
R.K. SINGH ◽  
A.K. BALANGE ◽  
P.A. KHANDAGALE ◽  
S.L. CHAVAN
Keyword(s):  
Feeding Behaviour ◽  
Control Diet ◽  
Sea Bass ◽  
The Other ◽  
Feeding Response ◽  
Lates Calcarifer ◽  
Total Length ◽  
Tank Experiment ◽  
Shrimp Head ◽  
Bombay Duck

Six purified diets were prepared for this experiment. Five of these six diets contained fish meals of five different fishes namely Bombay duck, Anchovy, Lesser sardine, Ribbon fish and shrimp head as natural stimulants for sea bass fry and juveniles. These five diets were prepared by adding 10% of each stimulant by weight in the purified diet. The sixth diet (F) was without stimulant and considered as control. The experiment was conducted on sea bass fry, 20 (+0.02) mm total length and juvenile, 217 (+0.15) mm total length by using one fish and two fish per tank respectively. The results indicated that Bombay duck meal containing diet i.e. diet ‘A’ has significant stimulating effect on the feeding behaviour of fry and also in juveniles of sea bass although the positive responses were higher in the case of juveniles (30 in case of fry and 34 in case of juveniles). Further, there were 34 positive responses in the case of two juvenile sea bass per tank experiment where as it was 30 in the case of two fry per tank experiment. The feeding responses were significantly different with two fish per tank as compared to one fish per tank showing that the number of fish had an influence on the feeding behaviour of both fry and juveniles. However, no feeding response was observed in the control diet. The study also revealed that Bombay duck meal is better and superior as feeding stimulant over the other fish meals for the Sea bass fry and juveniles.

Long-term consistency despite cross-seasonal changes in personality traits of common waxbills

Behaviour ◽  
2020 ◽  
Vol 157 (8-9) ◽  
pp. 781-806
Author(s):  
Soraia Guerra ◽  
Ana Cristina R. Gomes ◽  
Gonçalo C. Cardoso
Keyword(s):  
Individual Differences ◽  
Personality Traits ◽  
Breeding Season ◽  
Seasonal Changes ◽  
Tonic Immobility ◽  
Longitudinal Change ◽  
Personality Differences ◽  
Long Term Stability ◽  
Proactive Behaviour

Abstract Tests of long-term consistency in personality differences are not abundant. We studied personality in common waxbills (Estrilda astrild) from one Autumn to the next, and also from Autumn to a subsequent Spring, using a behavioural assay for their proactive-reactive personality axis (mirror test) and for tonic immobility. From one Autumn to the next, individual differences were consistent and the population median behaviours did not change, indicating long-term stability of personality differences. From Autumn to Spring, behavioural differences remained consistent, despite the population shifting to more proactive behaviour and individual differences being accentuated in the proactive-reactive personality axis. This increase in personality differences was not found between the two previous Autumns, suggesting a seasonal rather than longitudinal change, and a possible role for personality differences during the Spring breeding season. We conclude that waxbill personality differences are stable in the long term, despite changes in behaviour between Autumn and Spring.

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