Gonadal Development Cycle Research Articles

Erratum to: Effects of spatial variability and colony size on the reproductive output and gonadal development cycle of the Mediterranean red coral (Corallium rubrum L.)

Unfortunately Table 3 contained errors. The correct Table 3 is shown below:

Effects of spatial variability and colony size on the reproductive output and gonadal development cycle of the Mediterranean red coral (Corallium rubrum L.)

Red coral (Corallium rubrum, L. 1758) is an over-exploited Mediterranean gorgonian. The gonadal development cycle of this gorgonian is examined at the Costa Brava (NW Mediterranean) taking into account for the first time colony size, depth and spatial horizontal variability. This study compares the gonad development and fertility in two colony size classes (colonies 10-cm height, both at 40–45-m depth), and two populations at different depths (16–18-m depth, and 40–45-m depth, both consisting of 12 cm high colonies, in 2 cm intervals) was examined in the deep population, where large colonies were present. Furthermore, reproductive output was compared in 6 populations (distributed along more than 70-km coastline) one month before spawning (June). Red coral was found to be dioecious and gonochoric with a sex ratio of 1:1, which differs from other NW Mediterranean populations. On the other hand, fertility of different size classes indicates that small colonies of 2-cm height already produce gonads, which is in line with previous studies. Female and male polyp fertility and sperm sac size increase significantly with colony size [sperm sac diameter: 476±144 μm (mean±SD) and 305±150 μm in the >10-cm and 12 cm, thus the recommendation of this study is that a minimum height should be incorporated into fishing regulations. The six studied populations at the Costa Brava showed a comparable reproductive potential, which demonstrates little variability within the homogenous population structure and range of size classes (due to overharvesting) found at the Costa Brava. The study of reproductive output is an important tool for ecosystem management, and this work recommends basing specific exploitation laws for distinctive populations on colony size, which is found to have a larger effect on reproductive potential than mesoscale variability.

Non-invasive assessment of reproductive status and cycle of sex steroid levels in a captive wild broodstock of Senegalese sole Solea senegalensis (Kaup)

Senegalese sole, Solea senegalensis, intensive culture is currently limited mainly due to the low control on reproduction in captivity. Comprehensive knowledge of reproductive biology and physiology for this species is needed in order to improve tank spawning success. This work describes for the first time the seasonal profiles of plasma levels of sex steroids (17β-estradiol, testosterone, 11-ketotestosterone, and 17,20β-dihydroxy-4-pregnen-3-one [17,20β-P]) in a S. senegalensis captive wild broodstock held under natural conditions, during two consecutive reproductive cycles. Changes in apparent maturation in females, dynamics of sperm release in males, and the condition factor ( K) were monitored. Six maturation stages were established for females according to apparent size of the ovary and external abdominal swelling: early, intermediate and final ovarian development (F2+, F3+ and F4+, respectively), and partially spawned, mid spawned and spawned out or regressed (F3−, F2−, and F1−, respectively). During summer, F1− and non-running males (NRM) were predominant in association with low K and plasma steroid levels. At the end of summer, a new cycle of gonadal development started, denoted by the increase in reproductive parameters ( K and steroid levels) and the appearance of F2+. By middle autumn, some females reached advanced maturation stages (F3+ and F4+) while the proportion of running males (RM) showed a maximum. An occasional spawning could be registered during this season (November 2002). Towards the end of winter and beginning of spring, ovarian development reached its maximum. At this point, the proportion of F3+, F4+ and RM, K (specially in females), and steroid concentrations were the highest in concordance with the starting of the main spawning period (lasting from January to June 2003 and from March to June 2004). Throughout this period, concomitantly with oocyte and sperm release, the proportion of F3−, F2−, F1− and NRM progressively increased, while steroid levels and K progressively declined (concentration of steroids could fluctuate under a decreasing trend). The relatively elevated levels of 17,20β-P correlating with some parts of the spawning periods makes it a candidate for the role of the maturation-inducing steroid in S. senegalensis. Seasonal variations of measured parameters were consistent with the reproductive cycle of this species in the wild, and comparable to those found in other asynchronous multi-spawning fish.

An annual cycle of steroid hormone concentrations and gonad development in the winter skate, Leucoraja ocellata , from the western Gulf of Maine

The winter skate, Leucoraja ocellata (Mitchill, 1815) is a large oviparous skate that is endemic to inshore waters of the western North Atlantic. The reproductive cycle of this species was characterized in monthly samples taken off the coast of New Hampshire, USA (42°15′N; 70°25′W), at depths of 9–107 m from November 2000 to October 2001. Plasma concentrations of the sex steroids testosterone (T), 17β-estradiol (E2), and progesterone (P4) were determined by radioimmunoassay in mature male and female skates. Changes in ovary weight, shell gland weight, and follicle size for 66 female skates were compared to patterns of all three steroid hormones. Beginning in January, ovary weight, shell gland weight, average diameter of the largest follicle, and plasma E2 increased steadily, culminating in a transient peak in July. This peak was followed by a steady decline in plasma E2 concentrations, which returned to the lowest values in December. Although T concentrations fluctuated throughout the year, a low concentration in July coincided with a peak in E2. Skates sampled in September, October, and November had the highest P4 concentrations, coinciding with the period of egg-case production. For males (n=64), annual cycles of T and E2 were compared to stages of spermatogenic development. Testosterone concentrations displayed two peaks, one in December/January and the other in July, which were associated with maximum spermatocyst concentration, while E2 peaks in February, June, and October coincided with maximum spermatocyte concentration. Along with our observations that some reproductive individuals were present throughout the year, these findings suggest that the winter skate has a partially defined reproductive cycle.

대복 (Gomphina veneriformis)의 생식소 발달과 생식주기

Gonadal development and gametogenic cycle of the equilateral venus, Gomphina collected in the coastal waters of Gangneung, Gangwon-do, Korea were investigated by means of histological method from March 2001 to February 2002. Sex of the clam was dioecious. The gonads are composed of a number of gametogenic follicles. The gonad index (GI) was reached the maximum in June (3.87), and the minimum in August (0.66). The condition index (CI) was reached the maximum in May (0.051), and the minimum in January (0.028). The gametogenic cycle of the clam could be divided into five stages inactive (September to November), early active (November to March), late active (April to May), ripe (June and July) and spent/degenerative stage (July to August). Sex ratio (male/female) was 1:0.9.

Gametogenic cycle of the transplanted-cultured pearl oyster, Pinctada fucata martensii (Bivalvia: Pteriidae) in Korea

The gonadal development and gametogenic cycle of transplanted-cultured pearl oyster, Pinctada fucata martensii , were investigated using individuals collected monthly from Tong-Young along the south coast of Korea from October 2000 to September 2001. The result of monthly change of condition index was similar to tissue weight rate. The highest value was observed in June and the lowest value was observed in November. The gonad of the pearl oyster was located around the digestive diverticula. The ripe testis was milky white while the ovary was light brown. The spawning period of the pearl oyster extended from April to August, with a peak between June and July. The gametogenic cycle could be classified into five successive stages: multiplicative stage (November to February), growing stage (January to March), mature stage (March and April), spawning stage (April to August) and resting stage (September to November).

Seasonal variation in the reproductive activity of the wild rabbit (Oryctolagus cuniculus algirus) in a Mediterranean ecosystem

To establish a successful strategy for managing wild rabbit (Oryctolagus cuniculus algirus) populations it is essential to have a clear understanding of reproductive biology. In Portugal, previous work suggested a seasonal pattern of reproductive activity for this species. In this study we present additional information on the seasonal reproductive activity of the wild rabbit as well as data on the influence that environmental factors have on the onset and length of the breeding season. The study was carried out in Pancas, southern Portugal, from October 1997 to September 1998. Rabbits were collected every two months and post mortem analyses were performed. In the males, circulating concentration of testosterone, gonadal weight, daily sperm production, diameter of the seminiferous tubules and the thickness of epithelial cells were measured. The numbers of corpora lutea, embryos and placental scars were recorded in the females. To assess abundance and quality of food, samples of herbaceous vegetation were collected and analysed for water, fibre and crude protein content. The reproductive season extended from November to June with a peak in March/April, with both sexes showing an annual cycle of gonadal development and subsequent regression. All analysed females were pregnant and/or lactating between March and June. The mean litter size estimated by counting the embryos in the uteri was 3.90 ± 0.50. Daily sperm production was highest between November and April. Testicular function was strongly correlated with environmental temperature and the water content of the vegetation, and both testicular and ovarian development were correlated with vegetation biomass.

Seasonal and age-related changes in blood parasite prevalence in Dark-eyed Juncos (Junco hyemalis, Aves, Passeriformes).

We determined seasonal changes in blood parasite infections in a free-living population of Dark-eyed Juncos (Junco hyemalis) breeding in interior Alaska (65 degrees N; 148 degrees W). The common parasites found in blood smears were Leucocytozoon fringillinarum (56%), Trypanosoma avium (33%), and Haemoproteus fringillae (9%). In males, parasite prevalences were relatively high at arrival on breeding grounds and increased during the breeding season. Intensity of infection with Leucocytozoon also increased between spring and summer, and then decreased at the time of migration (September). This decrease did not occur in adult females. Elevated prevalences during the breeding season probably reflected the addition of new cases via vector activity to positive status resulting from spring relapse. We observed neither an association between parasite species nor a consistent relationship between parasite intensity and body condition. To further study relationships between reproductive system activity and parasite infections, we compared prevalences in adult males that were undergoing their first cycle of gonadal development and regression (males in their second calendar year, or SY) with those of older males (males in their third or more calendar year, i.e., after-second-year males or ASY). Circulating testosterone concentrations declined in both groups between arrival on breeding grounds (end of April-early May) and the end of the reproductive period (July), and they were higher in May in ASY than in SY males. At the peak of the breeding season (June), ASY males also had a higher parasite prevalence than SY males. This difference may have resulted from immunosuppressive effects of gonadal hormones and/or from behavioral differences between SY and ASY males such that older males were exposed to more insect vectors than younger males. .

Reproduction of the commercial scallop, Pecten fumatus, Reeve, 1852 in Bass Strait, Australia

To examine the reproduction of Pecten fumatus Reeve, 1852, samples were taken monthly from beds off King Island and in Banks Strait, from July 1986 to July 1987. For each sample the mean gonad-free tissue weight and standardized gonad weight were calculated. The percentage of the sample with each of five macroscopically determined reproductive stages was also measured. Changes in the proportion of cell types within the ovarian part of the gonad were determined by histological and stereological methods. A seasonal cycle of gonadal development occurred at each site, commencing at the time of lowest water temperatures and highest nutrient concentrations. This development progressively increased as the nutrient concentrations declined. No correlation was seen between chlorophyll a and gonad condition. A synchrony in gonad condition was present among individuals in samples; this was greatest at Banks Strait where gonads were larger, and phosphate, nitrate and silicate concentrations were significantly greater. There was no reduction in somatic tissue weight with increase in gonad tissue weight. Maximum gonad development preceded spatfall at each site by about one month.

Seasonal changes in condition, nutrition, gonad maturation and energy content in barbel, Barbus sclateri, inhabiting a fluctuating river

The objective of this study was to investigate the seasonal cycle of condition, nutrition and gonad development, as well as the magnitude of seasonal variations in energy content of somatic and gonad tissues in juveniles, males and females of Sclater's barbel, Barbus sclateri, from the upper Guadalete River (south Spain). The influence of reproductive cycle on somatic changes was also investigated and discussed. Measurements of condition factor (K), somatic index (SI), gonadosomatic index (GSI) and somatic and gonad energy content (J g-1 dw) were made in individual specimens taken from the Guadalete River monthly for 12 months. This freshwater ecosystem is characterised by strong seasonal fluctuations in water and flow level, temperature and food supply. It was found that in general juveniles, males and females of barbel exhibited a similar condition, nutrition and somatic energy cycle throughout the year, with the highest values in spring and the lowest in summer. Depletion of K, SI and somatic energy storage from spring until mid-summer seems to be associated with high metabolic demands during this period, and in adult fish also with spawning-related activity. The gonad index and energy content of the gonad were the highest in April and the lowest in summer for both sexes. Spawning took place during late spring – early summer, with fish quiescent by mid summer. The energy required for ovarian development (3970 J g-1 dw) was greater than the one for testes development (2763 J g-1 dw). Data on gonad energy content indicated a period (March to April) of intense energy accumulation (64% males and 37% females) which was related to the decline in the average somatic energy content in males and females. The somatic energy content was linearly related to K and SI. In the same way, GSI correlated positively with gonad energy. Linear trends were found between somatic parameters (K, SI and energy content) and gonad parameters (GSI and energy content).

Seasonal variations in the physiological status and energy content of somatic and reproductive tissues of chub

The seasonal fluctuations in condition, nutrition and somatic energy content, and gonad development cycle were investigated in chub Leuciscus pyrenaicus from the headwaters of the Guadalete River, a freshwater ecosystem characterized by strong seasonal fluctuations in discharge and water level, temperature and food supply. The relationship between somatic stage and gonad cycle was also investigated and discussed. Condition, nutrition and somatic energy cycles could be divided into two distinct periods: from April to January with summer decreases and autumn increments, which is common for juveniles and mature fish; and from January to March, when juveniles and mature fish displayed different temporal variations related to the reproductive cycle. Gonad development took place from the end of the winter into the summer, the testes developing before the ovaries. Spawning started in late spring (May) and continued into summer (June and July), with fish quiescent by autumn (September). The results suggest that, for L. pyrenaicus, both environmental factors (e.g. food supply, water temperature) and reproduction needs affect the condition, nutrition and somatic energy storage of fish, which have been used as indicators of the physiological status of the population.

Seasonal adaptations of Siberian hamsters. II. Pattern of change in daylength controls annual testicular and body weight rhythms.

Studies of rodent photoperiodism almost without exception have employed fixed day lengths (DLs) and abrupt transitions from long to short DLs. Because the natural progression of changes in DL carries predictive information and may have physiological consequences, we determined seasonal fluctuations in testis size and body weight in Siberian hamsters maintained in a year-long pattern of increasing and decreasing DLs. A cycle of gonadal development, regression, and recrudescence, and corresponding changes in body weight, were observed in hamsters maintained in separate simulated natural photoperiods (SNPs) in which DLs neither fell below nor exceeded the putative critical DL of 13 h. Gradually decreasing DLs as long as 15.3 h induced gonadal regression, and DLs as short as 12.3 h supported ponderal growth, depending on the hamster's prior photoperiodic history. DLs experienced by hamsters during development influenced the adult incidence of responsiveness to short DLs. Photorefractoriness to short DLs occurred earlier in hamsters kept in static 10-h than in 12-h DLs. Increasing DLs in winter had little impact on the rate of gonadal recrudescence and weight gain. These data extend earlier investigations in showing the photoperiodic history determines gonadal responses over a broad range of DLs and influences gonadal responsiveness to short DLs and the triggering of the interval timer underlying recrudescence.

Reproduction and cycle of gonadal development in the Mediterranean gorgonian Paramuricea clavata

Reproduction and cycle of gonadal development in the Mediterranean gorgonian Paramuricea clavata

Plasma Levels of Prolactin and Gonadotropins during the Reproductive Cycle of White-Crowned Sparrows (Zonotrichia leucophrys)

Abstract Plasma concentrations of prolactin, LH, and FSH were measured in free-living pairs of Zonotrichia leucophrys pugetensis throughout the natural breeding season, and during a photoperiodically induced cycle of gonadal development and regression in both sexes of captive Z. l. gambelii under controlled conditions. In free-living male Z. l. pugetensis plasma levels of FSH, which correlate well with changes in testicular weight reported previously, are higher than in females. Although only females of this species incubate, maximal levels of prolactin are observed in both sexes during late incubation. This is consistent with observations in other avian species and suggestive of a role for prolactin in incubation and associated parental behavior. The temporal association of elevated FSH with high levels of prolactin in females may represent a mechanism for maturation of ovarian follicles for the next clutch in this race, which typically raises as many as 3 broods per season. In the laboratory study on Z. l. gambelii, prolactin secretion in both sexes appears to have been induced photoperiodically in the absence of other environmental stimuli associated with incubation. The time course and magnitude of plasma prolactin levels were similar in both sexes, although levels were considerably lower than values obtained from incubating birds during the field study. Plasma levels of LH and FSH in females increased rapidly in response to photostimulation and began to decline after one week, whereas in males the pattern of increase and decrease of both gonadotropins was more gradual.

Gonad development and the planulae of the temperate Australian soft coral Capnella gaboensis

Capnella gaboensis Verseveldt, 1977 was sampled at four sites in Sydney Harbour, during 1981–1984. This soft coral has an annual cycle of gonad development, with gonad number reaching a peak in May several weeks prior to spawning, and gonad size reaching a peak in May–June at spawning. The gonads develop during the warm months, and colonies spawn their gametes in late autumn and early winter. Gonad development is neither synchronous within colonies nor within populations, possibly reflecting the protracted nature of spawning. The histology of the developing oocytes and spermaries is described in detail C. gaboensis is a surface-brooder. The planulae are similar in structure to the larvae of other octocorals. The larvae are benthic, settling quickly upon suitable substratum, metamorphosing into polyps with mouths, tentacles and spicules, approximately one week after settling.

Thyroid and annual gonad development, body weight, plumage pigmentation, and bill color cycles of lal munia, Estrilda amandava

Long-term administration of l-thyroxine (T 4) in the wax bill (lal munia) inhibited the current gonad development cycle, and the increase in gonadal volume in the second cycle was suppressed only by higher concentrations. Gonadal inhibition by high but not by low doses of l-T 4 was associated with a failure in the development of LH-dependent pigmented nuptial plumage. This suggests that l-T 4 depresses FSH secretion more readily than LH secretion. The results indicate that the effects of l-T 4 administration on the body weight cycle depends upon the physiological and/or gonadal status of the bird at the start of the experiment and that the juvenile hhpothalamo-hypophysial-gonadal axis is more sensitive to l-T 4 than that of the adult birds. The bill color, like plumage pigmentation, appears to be LH controlled. It is suggested that while thyroid hormone, acting by way of the hypothalamo-hypophysial complex and/or by direct action on the feather papillae, modulates the annual cycles of plumage pigmentation, bill color, gonad development, and body weight of lal munia, the finch has an endogenous mechanism which enables it to adapt to chronic hyperthyroidism in such a way that breeding occurs at the normal time of the year.

Broodstock management of Crassostrea gigas: Environmental influences on broodstock conditioning

Maximum larval survival is realized when broodstock are in an optimum stage of gonadal development and the efficiency of larval culture may be substantially improved by using only optimally conditioned broodstock. The conditioning requirement to bring broodstock into this optimum stage is dependent upon the stage of gonadal development at the commencement of conditioning and upon the rate of conditioning. The stage of gonadal development at the commencement of conditioning may be determined directly or inferred by understanding the annual cycle of gonadal development occurring in the broodstock. The rate of conditioning, on the other hand, is regulated by the conditioning environment. In the present study, we have observed the influence of three components of the conditioning environment: temperature, salinity, and supplemental feeding on the rate of gonadal development during hatchery conditioning of broodstock. The rate of gonadal development is a function of temperature intensity and time rather than accumulated thermal exposure. Salinity exerted a negative influence on the rate of development in oysters conditioned at salinity levels below 30 parts per thousand (ppt). Furthermore, when oysters conditioned at 20 ppt relative to 30 ppt were spawned and the larvae were reared under standardized hatchery conditions, larval survival was markedly reduced in the former. Fecundity of broodstock was 60% greater when fed an algal food supplement of the diatom Thalassiosira pseudonana relative to starved controls, although the rate of gonadal development and gamete viability was not significantly different. Using these empirically determined functions, a simplistic quatitative model may be employed to predict broodstock conditioning requirements in order to increase the proportion of optimally conditioned brood oysters.

Observations on the age, growth, reproduction and food of the chub Squalius cephalus (L.) in the River Stour, Dorset

Opercular bones from 399 chub from the River Stour, Dorset were used for age and backcalculated growth measurements. Scales were only used to aid the interpretation of difficult operculars. Annuli were laid down through the period mid‐April to mid‐June. Growth in length was minimal between October and March. Growth rates were similar to those published for chub in other European waters, but the Stour chub were longer‐lived and attained a greater ultimate size. Female chub grew faster than the males. Spawning occurred from late May into June and elaboration of the gonads took place between September and May. Immature chub had an annual cycle of condition; the 0 group having a maximum in August and older immature fish reaching their maximum in June. Both categories had a minimum condition in early spring. The cycle of gonad development affected the condition of mature fish. The numbers of eggs in chub of lengths 359–467 mm ranged from 27 000–65 000. Some females attained sexual maturity at age V or VI, but most by age VII. The majority of males matured at age V, though some at ages III or IV. Growth rates and year‐class strengths varied from year to year but independently of one another. Thirty‐one per cent of chub aged II and over belonged to the 1959 year class. Young chub ate insect larvae and small crustacea, but the occurrence of fish and macrophytes was greater in the diet of older fish.