Gametogenesis and spawning in the subtidal white clam Spisula solida, in relation to temperature

1999 ◽  
Vol 79 (4) ◽  
pp. 753-755 ◽  
Author(s):  
M.B. Gaspar ◽  
C.C. Monteiro
Keyword(s):  
Sex Ratio ◽  
Seawater Temperature ◽  
Condition Index ◽  
Gonadal Development ◽  
First Year ◽  
Southern Portugal ◽  
Males And Females ◽  
A Site ◽  
First Year Of Life ◽  
Definite Temperature

Seasonal variations in reproductive cycle of Spisula solida were studied between June 1995 and June 1996 at a site off Vilamoura, southern Portugal. Sex ratio was found to be in favour of males. Both males and females showed a synchronism in gonadal development and spawning. Gametogenic activity started with decreasing temperature at the beginning of autumn. The onset of spawning took place in February when the seawater temperature began to increase. Spawning ended in May. It is possible that the white clam does not spawn at a definite temperature, rather responding to the increase in seawater temperature. Between June and September, the specimens were found to be in the resting stage and the condition index increased, probably due to the accumulation of reserves. Spisula solida reached maturity during the first year of life.

Reproductive Cycleso Of the Razor Clam Ensis Siliqua and the Clam Venus Striatula off Vilamoura, Southern Portugal

1998 ◽  
Vol 78 (4) ◽  
pp. 1247-1258 ◽  
Author(s):  
M.B. Gaspar ◽  
C.C. Monteiro
Keyword(s):  
Gonadal Development ◽  
First Year ◽  
Razor Clam ◽  
Ensis Siliqua ◽  
Southern Portugal ◽  
Commercially Important ◽  
Males And Females ◽  
Reproductive Cycles ◽  
A Site ◽  
First Year Of Life

Annual reproductive cycles of two commercially important bivalves, the razor clam Ensis siliqua and the clam Venus striatula were investigated. Specimens of both species were sampled monthly from a site off Vilamoura, south of Portugal, between June 1992 and May 1993. Gonadal development was monitored using standard histological methods. Observed gametogenic progression was categorized by six stages: (0) inactive; (I) early active gametogenesis; (II) late active gametogenesis; (HI) ripe; (IV) partially spawned; and (V) spent. Both males and females showed a synchronism in gonadal development. The gametogenesis in the razor clam began in December and by late April the gonads were characterized morphologically by an abundance of ripe eggs and sperm. Partially spawned individuals were first encountered in May. All were spent by July. The gametogenic activity in V. striatula began in the months of October/November and continued until March. Spawning occurred between April and early August. Both species reached maturity during the first year of life.

scholarly journals ANÁLISIS DEL CRECIMIENTO Y LA MORTALIDAD DE ANISOTREMUS INTERRUPTUS (GILL) (PERCIFORMES: HAEMULIDAE) EN LA COSTA DE COLIMA, MÉXICO

2016 ◽  
Vol 33 ◽  
Author(s):  
Elaine Espino Barr ◽  
Manuel Gallardo Cabello ◽  
Fernando González Orozco ◽  
Arturo Garcia Boa
Keyword(s):  
Mortality Rate ◽  
Growth Parameters ◽  
Total Mortality ◽  
Condition Index ◽  
First Year ◽  
The Third ◽  
Second Year ◽  
First Year Of Life ◽  
Mortality Analysis

This paper deals with the growth and mortality analysis of the burrito grunt A n i s o t remus interru p t u s on the coast of Colima, México. The estimated growth parameters are: L¥ = 50.59 cm; W¥ = 5,051.04 g; k = 0.147 years- 1; to = -0.916 years; A0 . 9 5 = 19.46 years. Most of the growth occurred during the first year of life, when the grunt grows 12.52 cm, the second year it grows 4.95 cm and the third, 4.60 cm. The highest value of the condition index took place between February and September. The total mortality rate (Z) was calculated as 0.53 years- 1. These values are basic for the plan of administration of the fishery of this species.

Beberapa Aspek Reproduksi Siput Lambis lambis di Pesisir Perairan Yenusi, Biak

2016 ◽  
Vol 1 (3) ◽  
pp. 1
Author(s):  
Andriani Widyastuti ◽  
Ludi Parwadani Aji
Keyword(s):  
Sex Ratio ◽  
Management Strategies ◽  
Gonadal Development ◽  
Shell Size ◽  
Gonad Maturity ◽  
Males And Females ◽  
Over Exploitation ◽  
Number Of Males ◽  
Time Of Harvest

<strong>Some Aspects of Reproduction in Conch Lambis lambis of Yenusi Coastal Waters, Biak.</strong> Lambis lambis is a very popular conch species that has been harvested in all sizes encountered. This condition is very alarming because in the long term, its existence in nature will be reduced because there is no chance to reproduce naturally. This study aims to determine the sex ratio and gonad maturity levels of L. lambis in Yenusi waters, so the appropriate time of harvest can be arranged. Samples were collected every month from January to December 2013. Testing and histological analysis were performed in the laboratory. Samples collected were 99 individus with the number of males 45 individus and females 54 individus. The sex ratio of males and females was 1.0:1.2. Gonad maturity level found included all four stages of gonadal development, from TKG I to TKG IV. Gonadal development showed the process of formation and maturation, and the spawning occured throughout the year, with peak spawning in January until March 2013. The size of the shell length obtained ranged from 4.55 to 13.72 cm indicating over-exploitation. Due to the custom local where residents harvested the conches in all sizes found, sustainable management strategies are urgently needed, including moratorium period  when L. lambis is at the peak of spawning, and harvest should only be performed on adult individuals with a minimum shell size of 7 cm, while observing the thickness of the shell and marginal digitations have been formed. <br /><br />

Infantile Mortality

1930 ◽  
Vol 3 (04) ◽  
pp. 236-244
Author(s):  
John Blossom
Keyword(s):  
Continuous Improvement ◽  
Mortality Rates ◽  
Life Tables ◽  
First Year ◽  
Males And Females ◽  
First Year Of Life ◽  
Young Lives

There appears to be very little information, especially of recent date, relating to infantile mortality, in the publications of the Institute, and it is possible that a discussion upon the mortality of very young lives would be of service to those who have to deal with infantile assurances to any great extent.It is well known that infantile mortality rates have, generally, shown continuous improvement during the present century, and we cannot say that such rates have yet reached their lowest limit. For example, the deaths of males and females respectively during the first year of life as exhibited by successive English Life Tables are:—

Cranial ontogenetic variability, sex ratio and age structure of the Red fox

2010 ◽  
Vol 5 (6) ◽  
pp. 894-907 ◽  
Author(s):  
Martina Hartová-Nentvichová ◽  
Miloš Anděra ◽  
Vlastimil Hart
Keyword(s):  
Sex Ratio ◽  
Age Structure ◽  
Growth Pattern ◽  
Red Fox ◽  
Growth Patterns ◽  
First Year ◽  
Red Foxes ◽  
Female Ratio ◽  
One Year ◽  
First Year Of Life

AbstractDescribing the sex ratio, age structure of the population and ontogenetic variability of Red fox, Vulpes vulpes (Canidae, Carnivora) skull parameters, this study is based on 416 male and 289 female skulls collected in the Czech Republic. The skulls analysed came from feral individuals, that were shot by hunters. The male to female ratio was 1:0.69 regarding the whole population. Individuals younger than one year prevailed in the population (54% males, 48% females were in their first year of life). Four growth patterns of skull dimensions were described. The first group included mainly skull length dimensions (e.g. condylobasal length). They grew rapidly until the sixth month of life, becoming stabilised afterwards. The second group comprised parameters that were stable throughout the life (e.g. cheek tooth rows). Measurements representing the third growth pattern showed continual growth (mainly width dimensions, e.g. zygomatic breadth). Conversely, smaller dimensions of postorbital breadth were observed after the sixth month of life. Postorbital breadth represented the fourth growth pattern. It was concluded, that male and female Red foxes had similar ontogenetic skull development, even though there were some differences, e.g. in jugular breadth, which increased after the age of six months in males unlike in females.

scholarly journals Reproductive cycle of the mangrove oyster, Crassostrea rhizophorae (Bivalvia: Ostreidae) cultured in a macrotidal high-salinity zone on the Amazon mangrove coast of Brazil

2021 ◽  
Vol 51 (2) ◽  
pp. 113-121
Author(s):  
Ícaro ANTONIO ◽  
Ana SOUSA ◽  
Tiago LENZ ◽  
Izabel FUNO ◽  
Rodolf LOPES ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Reproductive Cycle ◽  
Condition Index ◽  
Gonadal Development ◽  
Reproductive Period ◽  
Salinity Zone ◽  
Crassostrea Rhizophorae ◽  
Reproductive Events ◽  
The Tropics ◽  
The Relationship

ABSTRACT This study aimed to establish the reproductive cycle of the mangrove oyster, Crassostrea rhizophorae cultured in the macrotidal estuary of the Paciência River, Maranhão state, on the northeastern coast of Brazil, and its relationship with environmental factors. Oysters were collected monthly throughout 2013 for histological analysis of sex ratio, gonadal development and condition index. The sex ratio was 1:1.39 (M:F) and only 5 specimens presented hermaphroditism. The breeding process was continuous throughout the year and mature (IIIA stage) and spawning oysters (IIIB stage) were present in practically all months. Low variation in temperature seemed to be the main factor for the continuity of the reproductive cycle. Besides temperature, the relationship between rainfall, salinity and primary productivity affected the stimulus and timing of reproductive events. The rainy season, with low values of salinity and high values of chlorophyll a and particulate organic matter, appeared to be the main reproductive period, with release of gametes and production and maturation of new gamete cohorts in the short term. In the tropics, where gamete maturation and release seem to be continuous and concomitant, the condition index does not appear to be the best method to assess reserve accumulation peaks and gonadal repletion.

scholarly journals Delayed start of first-time breeding and non-breeders surplus in the Western Siberian population of the European Pied Flycatcher

2018 ◽  
Author(s):  
Vladimir G. Grinkov ◽  
Helmut Sternberg
Keyword(s):  
Demographic Data ◽  
Pied Flycatcher ◽  
First Year ◽  
Siberian Population ◽  
Lower Saxony ◽  
Factors Affecting ◽  
Experimental Removal ◽  
Widespread Belief ◽  
Males And Females ◽  
First Year Of Life

ABSTRACTNon-breeders are those sexually mature individuals that do not breed in a given reproductive cycle of a population. There is a widespread belief that the presence of non-breeders can affect the actual population dynamics, as well as the population responses to environmental change (Lee et al. 2017). Sternberg (1989), using demographic data, has shown that 83% and 62% of males and females, respectively, do not breed in the first year of life in the Lower Saxony (Germany) population of the European Pied Flycatcher (Ficedula hypoleuca). Later, with experimental removal of males, it has been proven that in the Lower Saxony and Moscow Region (Russia) populations, there are many non-breeding males (Sternberg et al. 2002). For the Netherlands population of the European Pied Flycatcher, the presence of a large number of non-breeders has been demonstrated using experimental removals for both males and females (Both et al. 2017). Here we have estimated the number of non-breeders in the Western Siberian population of the European Pied Flycatcher using demographic data (11 cohorts from 2001 to 2011 of birth) and experimental removal of males. We have shown that both males and females can start to breed at the age of one to five years. The proportion of non-breeders can be 59.5% and 68.5% for first-year males and females, respectively. We discuss the differences in the proportion of non-breeders between the Western Siberian and European populations of the European Pied Flycatcher, as well as factors affecting the number of non-breeders.

scholarly journals Determination of the Sexual Maturity of Threadfins Polydactylus quadrifilis (Cuvier, 1829), Galeoides decadactylus (Bloch, 1795) and Pentanemus quinquarius (Linné, 1758) of the Artisanal Marine Fishery of Grand-Lahou (Ivory Coast)

2019 ◽  
pp. 1-9
Author(s):  
Kouassi Sylvain Konan ◽  
Ebram Luc Gervais Djadji ◽  
Yao Nicolas Amon ◽  
Konan N’da
Keyword(s):  
Sex Ratio ◽  
Sexual Maturity ◽  
Warm Season ◽  
Cold Season ◽  
First Year ◽  
Marine Fishery ◽  
Ratio Determination ◽  
First Maturity ◽  
First Year Of Life

Reproduction of the threadfins of the costal shelf of Grand-Lahou was studied with a monthly sampling frequencies range from may 2009 to april 2011. 534 specimens of Polydactylus quadrifilis, composed of 315 males and 219 females and 648 Galeoides decadactylus composed of 420 males and 228 females, then 453 individuals of Pentanemus quinquarius composed of 210 males and 243 females were used. The sexual maturity parameters of threadfins fishes indicate a size of first maturity (L50 = 67.5 cm) for females of Polydactylus quadrifilis and (L50 = 55.5 cm) with their males. Concerning  the specimens of Pentanemus quinquarius, females present (L50 = 15 cm) and their males (L50 = 14.5 cm). This parameter has identical values ​​with the females of Galeoides decadactylus (L50 = 15.5 cm) and their males (L50 = 15.5 cm). The individuals of Polydactylus quadrifilis and the specimens of Galeoides decadactylus and Pentanemus quinquarius become mature at 1 year of age. The sex ratio determination show that specimens of Polydactylus quadrifilis show a predominance of males during the warm season, from October (73.68%) to March (64.28%) which weakens during the cold season, from May (30%) to July (58%). For Galeoides decadactylus, the sex ratio shows a predominance of males, from August (88%) to March (94.73%). Concerning specimens of Pentanemus quinquarius, the sex ratio is in favor of the females whose lowest value is during the cold season in July (21.74%). All threafin species reach sexual maturity from their first year of life with different sex ratios variations.

scholarly journals Gonad Maturity and Fecundity of Bluecheek Silver Grunt (Pomadasys argyreus) in Palabuhanratu Bay, West Java

2020 ◽  
Vol 3 (1) ◽  
pp. 10-15
Author(s):  
Mona Agatha ◽  
Yonvitner ◽  
Rahmat Kurnia
Keyword(s):  
Sex Ratio ◽  
Condition Factor ◽  
Gonadosomatic Index ◽  
Gonadal Development ◽  
Gonad Maturity ◽  
Fish Samples ◽  
Males And Females ◽  
First Maturity ◽  
Partial Spawner ◽  
Fish Spawn

A total of 806 fish samples were collected from the catch of local fishermen. The sex ratio of Pomadasys argyreus was 1:0,90. Four stages of gonadal development were observed in males and females, which dominated by stage I and II (immature). The highest gonadosomatic index (GSI) in males was 1,14 in September, while in females was 1,80 in May. Length at first maturity of Pomadasys argyreus was 140,12 mm for males and 135,01 mm for females. The highest value of condition factor was 1,05 for males and 1,10 for females. This fish spawn partially (partial spawner) and estimated spawns throughout the year with a spawning peak in June.

The Development of Swallowing Respiratory Coordination

2009 ◽  
Vol 18 (1) ◽  
pp. 19-24
Author(s):  
Maggie-Lee Huckabee
Keyword(s):  
Cortical Activation ◽  
First Year ◽  
Healthy Children ◽  
Nasal Airflow ◽  
Single Session ◽  
Primary Finding ◽  
Patterns Of Behavior ◽  
Cortical Modulation ◽  
First Year Of Life ◽  
Swallowing Apnea

Abstract Research exists that evaluates the mechanics of swallowing respiratory coordination in healthy children and adults as well and individuals with swallowing impairment. The research program summarized in this article represents a systematic examination of swallowing respiratory coordination across the lifespan as a means of behaviorally investigating mechanisms of cortical modulation. Using time-locked recordings of submental surface electromyography, nasal airflow, and thyroid acoustics, three conditions of swallowing were evaluated in 20 adults in a single session and 10 infants in 10 sessions across the first year of life. The three swallowing conditions were selected to represent a continuum of volitional through nonvolitional swallowing control on the basis of a decreasing level of cortical activation. Our primary finding is that, across the lifespan, brainstem control strongly dictates the duration of swallowing apnea and is heavily involved in organizing the integration of swallowing and respiration, even in very early infancy. However, there is evidence that cortical modulation increases across the first 12 months of life to approximate more adult-like patterns of behavior. This modulation influences primarily conditions of volitional swallowing; sleep and naïve swallows appear to not be easily adapted by cortical regulation. Thus, it is attention, not arousal that engages cortical mechanisms.

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