Reproductive Status Modulates Mortality Rate, Lifespan and Egg Production, but Do Not the Physiological Aging in the Field Cricket Gryllus assimilis (Fabricius, 1775) (Orthoptera: Gryllidae)

2021 ◽  
Vol 50 (2) ◽  
pp. 237-246
Author(s):  
Guilherme Martins Limberger ◽  
Luiz Eduardo Maia Nery ◽  
Duane Barros da Fonseca
Keyword(s):  
Mortality Rate ◽  
Egg Production ◽  
Reproductive Status ◽  
Field Cricket ◽  
Physiological Aging

The fisheries management implications of maternal-age-dependent larval survival

2006 ◽  
Vol 63 (10) ◽  
pp. 2249-2258 ◽  
Author(s):  
Michael R O'Farrell ◽  
Louis W Botsford
Keyword(s):  
Mortality Rate ◽  
Fisheries Management ◽  
Maternal Age ◽  
Egg Production ◽  
Larval Mortality ◽  
Reproductive Potential ◽  
Larval Survival ◽  
Age Effects ◽  
Fishing Mortality ◽  
Black Rockfish

A common goal of conventional fisheries management is to maintain fishing mortality at a rate that ensures an adequate level of lifetime egg production (LEP) for population sustainability. However, larvae from young spawners can experience higher mortality rates than larvae of older spawners, reducing the effect of egg production by young females (hereafter, maternal age effects). This reduction leads to an error in LEP that can be accounted for by reducing the fishing mortality rate, but raises the question of the magnitude of these errors if they are present but not accounted for. Calculations using parameters from a typical long-lived fish demonstrated that maternal age effects resulted in large errors in estimates of lifetime reproduction when there was a large contrast in the larval mortality rate extending over the reproductive life span. Errors were small when maternal age effects reduced the reproductive potential of only the very youngest spawners, at ages when a small fraction of females are mature. A specific example using the empirically derived maternal age effect for black rockfish (Sebastes melanops) indicated that errors in traditional management would be small for this species.

Comparative performance of Vanaraja, Srinidhi and Desi chicken under traditional system among tribal community of Assam

2018 ◽  
Author(s):  
M. Sarma ◽  
R. Islam ◽  
M. K. Borah ◽  
P. Sharma ◽  
J. D. Mahanta ◽  
...  
Keyword(s):  
Body Weight ◽  
Mortality Rate ◽  
Field Condition ◽  
Egg Production ◽  
Reproductive Traits ◽  
Tribal Community ◽  
Comparative Performance ◽  
Egg Weight ◽  
Traditional System

A study was conducted covering a total of one hundred chicken farmers in tribal dominated Boko Block of Kamrup district in Assam to assess different productive and reproductive traits of Desi, Vanaraja and Srinidhi birds under field condition. Information was obtained on mean body weight at various ages, age at first egg, annual egg production, fertility and hatchability and mortality rate. Body weight, egg production and egg weight were significantly (P£0.05) higher in Vanaraja and Srinidhi birds compared to Desi chicken. The age at first egg was significantly (P£0.05) higher in Desi chicken while compared with Vanaraja and Srinidhi under traditional system of management. However no significant (P£0.05) difference was found between Vanaraja and Srinidhi in their body weight and egg production at various ages. Higher mortality percent in Vanaraja (12.23±1.62) and Srinidhi (11.34±1.23) were recorded during 0 to 5 week. No significant (P£0.05) differences were found among all three groups of birds in fertility and hatchability.

Estimation of change in lifetime egg production from length frequency data

2005 ◽  
Vol 62 (7) ◽  
pp. 1626-1639 ◽  
Author(s):  
Michael R O'Farrell ◽  
Louis W Botsford
Keyword(s):  
Mortality Rate ◽  
Reference Point ◽  
Egg Production ◽  
Growth Parameters ◽  
Estimation Method ◽  
Natural Mortality ◽  
Frequency Data ◽  
Length Frequency ◽  
Estimation Model ◽  
Length Frequency Data

The percentage of unfished lifetime egg production (LEP) has been used to represent persistence in precautionary fisheries management, but estimation of this reference point requires substantial data and it is sensitive to errors in natural mortality rate. We present an estimation method that quantifies the change in LEP by a fishery when only length frequency samples, one early in the fishery and one recent, are available for assessment. Using simulated length frequency data with known parameter values, estimates of LEP had undetectable bias when challenged with random sampling variability and sample sizes as low as 100. Simulation of artificial data with (i) growth parameters that differed from the estimation model, (ii) transient size structures, and (iii) recruitment variability led to predictably biased estimates. In a direct comparison with the spawning potential ratio reference point, fractional LEP was much less sensitive to errors in natural mortality rate. Application of this method to length frequency data for blue rockfish (Sebastes mystinus) for years between 1980 and 2003 suggests that during this interval, LEP has been reduced to levels of concern.

scholarly journals Performance of BLRI developed native duck under farmer’s condition with supplementary feeding

2016 ◽  
Vol 19 (1-2) ◽  
pp. 18-23
Author(s):  
H Khatun ◽  
MN Islam ◽  
AA Bhuyan ◽  
MN Hasan ◽  
MS Islam
Keyword(s):  
Weight Gain ◽  
Mortality Rate ◽  
Production Rate ◽  
Egg Production ◽  
Live Weight ◽  
Cost Benefit ◽  
Supplementary Feeding ◽  
Live Weight Gain ◽  
Significant Difference ◽  
Egg Production Rate

A total of 198 straight run day old ducklings of Bangladesh Livestock Research Institute (BLRI) developed native duck (named as Rupali and Nageswary) and local native duck genotypes were distributed among nine farmers of low laying areas of Kalihati Upazilla of Tangail district. Rupali and Nageswary ducklings were obtained from existing stock of BLRI and local native ducklings were collected from local farmers of the study area. After 12 weeks of age each farmers retained 10 female and 2 male ducks and sold away remaining ducklings. Farmers’ were instructed to supply 50g of balanced feed to their ducks in the morning and evening. Ducks were allowed to scavenge in the beel throughout the day. Data on: growth, feed intake, age at onset of lay, egg production rate, egg weight, mortality rate were recorded and cost-benefit was calculated. There found no significant difference on growth parameters, live weight gain, age at first laying or age at peak egg production among the duck genotypes. In the study highest live weight gain was found in Nageswary (1090 g) followed by Rupali (1058 g) and local native (912 g) duck at 8 weeks of age. Egg production rate of local native ducks (37.21%) was found significantly lower (P<0.001) compared to Rupali (50.67 %) and Nageswary (55.40 %). The mortality rate in local duck was significantly higher (P<0.05) compared to Rupali and Nageswary ducks. Rupali ducks produced heavier eggs (66.86g) followed by local native (62.20g) and Nageswary (57.22g) which differed significantly (P<0.05). Rupali ducks laid eggs of thicker shell (0.61mm) compared to other duck genotypes under study which was also varied statistically (P<0.05). Cost benefit analysis shows that earning both from Nageswary and Rupali was much higher than local native ducks. Higher egg production rate of Nageswary and Rupali duck has contributed for higher return. It is concluded that rearing Rupali or Nageswary ducks in the low laying rural areas with scavenging and supplementary feeding facility is more profitable than rearing local native ducks.Bangladesh J. of Livestock Res. 19(1-2): 18-23, Jan-Dec 2012

scholarly journals Assessment of long-term production traits of three breeds of exotic commercial layers in the derived Savannah zone of Nigeria

2011 ◽  
Vol 3 (1) ◽  
pp. 20-24
Author(s):  
S. O. Olawumi ◽  
I. Dudusola
Keyword(s):  
Mortality Rate ◽  
Feed Efficiency ◽  
Egg Production ◽  
Production Traits ◽  
Mean Values ◽  
Production Period ◽  
Savannah Zone ◽  
Dominant Black ◽  
Effect Of Age

This study was carried out to compare production traits of three breeds of exotic commercial layers for a production period of 15 months. The breeds are Isa Brown (IB), Bovan Nera (BN) and Dominant Black (DB) and the traits considered are hen-day egg production, feed efficiency and mortality rate. The general means are 5.24eggs/ bird/week, 0.006/bird/week and 0.16/breed/week for egg production, feed efficiency and mortality rate, respectively. There was highly significant (P<0.01) effect of breed on egg production and feed efficiency but the reverse was the case for mortality rate. On egg production, IB genotype recorded 5.37+0.07 eggs/bird/week while BN breed had 5.41+0.08 eggs/bird/week and the values were similar but superior to DB genotype with 4.94eggs/bird/week. For feed efficiency, IB and BN breeds recorded higher mean values and were similar but superior to DB genotype. The mean values are: IB=0.006+9.05x10-5, BN=0.006+8.53x10-5 and DB=0.005/bird/week. Breed’s effect on mortality rate showed that the three genotypes had similar values, that is, breed has no significant (P>0.05) effect on this trait. There was highly significant (P<0.01) effect of age of birds on egg production. Age 2 (2nd month) recorded the highest mean values while age 14 (14th month) was the lowest. The values respectively, are 6.04+0.16 eggs/bird/week and 4.18+0.16 eggs/bird/week. In addition, there was highly significant (P<0.01) effect of age of birds on feedefficiency regardless of the breed of birds. Age 2 (2nd month) recorded the highest mean values and age 14 (14th month) the lowest. There was also highly significant (P<0.01) effect of age on mortality rate of commercial layers. The long-term production analyses showed that IB and BN genotypes are more productive, feed efficient and could be recommended to farmers as commercially viable breeds of layers.

scholarly journals Effects of Temperature and Salinity on Egg Production, Hatching, and Mortality Rates in Acartia ohtsukai (Copepoda, Calanoida)

2021 ◽  
Vol 8 ◽  
Author(s):  
Seo Yeol Choi ◽  
Eun Hye Lee ◽  
Ho Young Soh ◽  
Min-Chul Jang
Keyword(s):  
Mortality Rate ◽  
Water Temperature ◽  
Mass Culture ◽  
Egg Production ◽  
Fish Larvae ◽  
Effect Of Temperature ◽  
Live Prey ◽  
Good Potential ◽  
Egg Production Rate ◽  
Almost All

The calanoid copepod Acartia ohtsukai predominates the estuarine and coastal waters of East Asia during summer. Its occurrence characteristics confer it with good potential as live prey for fish larvae through mass culture. To investigate the effect of temperature and salinity combinations on its egg production rate (EPR), hatching success (HS), and mortality rate, experiments were undertaken and repeated three times for combinations of five temperatures (10, 15, 20, 25, and 30°C) and seven salinities (10, 15, 20, 25, 27, 30, and 33 psu). EPR and HS were highest at temperatures of 25 and 30°C, respectively, with a salinity of 27 psu. Mortality rate was highest at 10°C in almost all salinity gradients, whereas it was lower at water temperature and salinity ranges of 20–30°C and 20–30 psu, respectively. These findings indicate that A. ohtsukai can inhabit wide ranges of water temperatures and salinities, and that the optimized condition for mass culture is a combination of water temperature of 25°C and salinity of 27 psu.

Yield-per-recruit and egg-per-recruit analyses of the Omani abalone, Haliotis mariae

1995 ◽  
Vol 46 (3) ◽  
pp. 663 ◽  
Author(s):  
SA Shepherd ◽  
JL Baker ◽  
DW Johnson
Keyword(s):  
Mortality Rate ◽  
Sexual Maturity ◽  
Egg Production ◽  
Arabian Sea ◽  
Total Mortality ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Northern Arabian Sea ◽  
Size At Sexual Maturity ◽  
Yield Per Recruit

The fecundity, size at sexual maturity, sex ratios and total mortality of Haliotis mariae on the Dhofar coast of the northern Arabian Sea were measured. These data, and estimates of the growth rate, were used for yield-per-recruit and egg-per-recruit analyses. Maximum yields occur at 3+ to 4+ years of age, depending on the natural mortality rate chosen. At the present age at first capture egg production levels are 2-29% of the unfished stock, depending on estimates of the fishing mortality rate and the natural mortality rate, and are considered to be far too low to maintain recruitment. At 40% egg production, of the maximum possible the age at first capture is 4 to 4.5 years, i.e. 105-115 mm shell length, depending on site.

scholarly journals Mortality Rate in Relation to Egg Production

1949 ◽  
Vol 28 (5) ◽  
pp. 707-712 ◽  
Author(s):  
F.A. Hays
Keyword(s):  
Mortality Rate ◽  
Egg Production
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