Egg Production and Viability in Centropages Typicus: A Laboratory Study on the Effect of Food Concentration

1997 ◽  
Vol 77 (1) ◽  
pp. 257-260 ◽  
Author(s):  
Francisco Guerrero ◽  
Suzanne Nival ◽  
Paul Nival
Keyword(s):  
Production Rate ◽  
Egg Production ◽  
Food Concentration ◽  
Natural Food ◽  
Algal Culture ◽  
Effect Of Food ◽  
Food Conditions ◽  
Egg Production Rate ◽  
Food Media ◽  
Centropages Typicus

The effect of food concentration on the reproductive success of the copepod Centropages typicus (Copepoda: Calanoida) was studied in the laboratory. Three different regimes of food were tested: absence of food, natural food conditions and a food media enriched with an algal culture. The results showed significant differences in egg production rate between regimes of food, but no significant differences in egg viability. A rapid response (24 h) in egg production rate to increment in the quantity of food was noted. Hatching success was not affected by food conditions prevailing during the incubations.

scholarly journals Does resource availability influence the vital rates of the tropical copepod Apocyclops royi (Lindberg, 1940) under changing salinities?

2020 ◽  
Vol 42 (4) ◽  
pp. 467-478 ◽  
Author(s):  
Hans Van Someren Gréve ◽  
Per Meyer Jepsen ◽  
Benni Winding Hansen
Keyword(s):  
Production Rate ◽  
Food Availability ◽  
Egg Production ◽  
Food Concentration ◽  
Threshold Concentration ◽  
Cyclopoid Copepod ◽  
Vital Rates ◽  
Food Concentrations ◽  
Salinity Levels ◽  
Egg Production Rate

Abstract The physiology of invertebrates inhabiting many coastal ecosystems is challenged by strong temporal fluctuations in salinity. We investigated how food availability influences vital rates in the tropical cyclopoid copepod Apocyclops royi subjected to different salinities (5–32 PSU). We hypothesized that (i) mortality decreases and egg production rate increases with food availability; (ii) under suboptimal salinity, mortality increases and the egg production rate is reduced and (iii) the threshold concentration for egg production (the lowest food concentration where egg production is initiated) shifts to higher food concentrations when challenged by salinity. Surprisingly, A. royi survived, ingested food and produced eggs at all tested salinities. Mortality rate was, however, dependent on salinity level, but not on food availability. Mortality increased (~12% h−1) during short-term (1 h) salinity acclimatization to 5 PSU and during the following 24-h incubations (~5% d−1) compared with higher salinities. Feeding and egg production rates increased with food availability up to an optimum at all salinity levels, with no effect of salinity on the lowest food concentration initiating egg production. This reveals a high-salinity tolerance by A. royi and may partly explain why this particular copepod is so successful compared with its congeners in occupying extreme habitats.

Reproductive rate and longevity in the waterstrider, Gerris buenoi

1990 ◽  
Vol 68 (2) ◽  
pp. 399-402 ◽  
Author(s):  
Locke Rowe ◽  
G. G. E. Scudder
Keyword(s):  
Egg Production ◽  
Life History Theory ◽  
Reproductive Rate ◽  
Food Level ◽  
Central Component ◽  
Effect Of Food ◽  
Food Conditions ◽  
Female Longevity ◽  
Egg Production Rate ◽  
The Relationship

In this laboratory study, the relationship between egg output and longevity at three food levels is examined in adults of the waterstrider, Gerris buenoi. There was no effect of food level on estimated lifetime fecundity. However, egg production rate was halved under low food conditions. This reduction in reproductive rate was balanced by a near doubling of female longevity under food scarcity. Males lived longer than females, but longevity was not significantly related to food level. Egg fertility was not significantly different across treatments. Body size accounted for less than 5% of the variation in all these variables. These data support a central component of life history theory: the assumption that there is a trade off between reproductive rate and longevity.

Ecology of Pseudodiaptomus annandalei in tropical aquaculture ponds with emphasis on the limitation of production

2019 ◽  
Vol 41 (5) ◽  
pp. 741-758 ◽  
Author(s):  
Josephine GrØnning ◽  
Nam X Doan ◽  
Nguyet T Dinh ◽  
Khuong V Dinh ◽  
Torkel Gissel Nielsen
Keyword(s):  
Production Rate ◽  
Egg Production ◽  
Fecal Pellet ◽  
Temperature Dependent ◽  
Egg Hatching ◽  
Pellet Production ◽  
Live Feed ◽  
Egg Production Rate ◽  
Tropical Aquaculture

ABSTRACT The calanoid copepod Pseudodiaptomus annandalei is used as live feed in aquaculture because of its nutritional value and the ability to cope with environmental fluctuations in outdoor ponds. However, little knowledge exists on its ecology. Here we investigated the ecology of P. annandalei in an aquaculture pond in Vietnam. Temperature, salinity, chlorophyll a and biomass of protozoans and copepods were monitored every other day for 1 month. Experiments on protozoan growth and grazing by P. annandalei were also conducted. Copepod fecal pellet production and temperature-dependent egg hatching rates were likewise quantified. Despite very high phytoplankton biomass, biomass of P. annandalei was surprisingly low. Copepod production was estimated from three independent methods: clearance, weight-specific egg production rate (SEP) and specific fecal pellet production rate. SEP proved to be accurate to predict the in situ population growth in the pond. A simple model for production of P. annandalei based on SEP was developed. Our study extends our knowledge of how environmental conditions in the pond may affect the population dynamics and production of copepods. The results have important implications for pond managements ensuring stable copepod production and harvest.

scholarly journals Egg Production Rate and Fertility in Inbred Chickens

1948 ◽  
Vol 27 (6) ◽  
pp. 719-726 ◽  
Author(s):  
Wilbor O. Wilson
Keyword(s):  
Production Rate ◽  
Egg Production ◽  
Egg Production Rate

Life cycle of Calanus finmarchicus in the lower St. Lawrence Estuary: the imprint of circulation and late timing of the spring phytoplankton bloom

2001 ◽  
Vol 58 (4) ◽  
pp. 647-658 ◽  
Author(s):  
Stéphane Plourde ◽  
Pierre Joly ◽  
Jeffrey A Runge ◽  
Bruno Zakardjian ◽  
Julian J Dodson
Keyword(s):  
Population Dynamics ◽  
Life Cycle ◽  
Production Rate ◽  
Egg Production ◽  
Phytoplankton Bloom ◽  
Food Limitation ◽  
Calanus Finmarchicus ◽  
Lawrence Estuary ◽  
Egg Production Rate ◽  
St Lawrence Estuary

The life cycle of Calanus finmarchicus in the lower St. Lawrence estuary is described based on observations of female egg production rate, population stage abundance, and chlorophyll a biomass collected over 7 years (1991–1997) at a centrally located monitoring station. The mean seasonal pattern shows maximum abundance of females in May, but peak population egg production rate and naupliar (N3–N6) abundance occur in early July just after onset of the late spring – early summer phytoplankton bloom. The population stage structure is characterized by low summer abundance of early copepodite stages C1–C3 and high stage C5 abundance in autumn. Between 1994 and 1997, there was important interannual variation in both timing (up to 1 month) and amplitude (five- to eight-fold) of population reproduction. Patterns of seasonal increase of C5 abundance in autumn suggest interannual variations of both timing and magnitude of deep upstream advection of this overwintering stage. Thus, the main features of C. finmarchicus population dynamics in the central lower St. Lawrence Estuary are (i) late reproduction resulting from food limitation prior to the onset of the summer phytoplankton bloom, (ii) probable export of early developmental stages during summer, and (iii) advection into the central lower St. Lawrence Estuary of overwintering stage C5 in autumn from downstream regions. These results support the hypothesis that circulation, mainly driven by discharge from the St. Lawrence River and its tributaries, is a key factor governing population dynamics of C. finmarchicus in this region.

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

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