Measurement of Egg Production Rate of Calanus finmarchicus from Preserved Samples

1987 ◽  
Vol 44 (11) ◽  
pp. 2009-2012 ◽  
Author(s):  
Jeffrey A. Runge
Keyword(s):  
Nova Scotia ◽  
Water Column ◽  
Production Rate ◽  
Egg Production ◽  
Gonadal Development ◽  
Calanus Finmarchicus ◽  
Production Rates ◽  
Daily Production ◽  
Egg Production Rate

A method for determining Calanus egg production rates from preserved, net-tow samples is proposed. In the sea off Nova Scotia, in situ egg production rates (eggs per female per day) of Calanus finmarchicus are significantly related to an index of gonadal development in preserved females. This relationship could be used in combination with data on female abundance to estimate daily production of eggs in the water column. The method is illustrated with data from a transect across Browns Bank.

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.

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.

Egg production rates of Calanus finmarchicus in the western North Atlantic: effect of gonad maturity, female size, chlorophyll concentration, and temperature

2000 ◽  
Vol 57 (3) ◽  
pp. 518-529 ◽  
Author(s):  
Robert W Campbell ◽  
Erica JH Head
Keyword(s):  
Egg Production ◽  
Chlorophyll Concentration ◽  
Calanus Finmarchicus ◽  
Female Gonad ◽  
Female Size ◽  
Production Rates ◽  
Gonad Maturity ◽  
Spatial And Temporal Scales ◽  
Female Body Size ◽  
Egg Production Rate

Egg production rates of Calanus finmarchicus were measured in the Labrador Sea (spring) and on the Scotian Shelf (spring, summer, and autumn), in conjunction with indices of gonad maturity and food availability, female body size, surface layer temperature, and surface nitrate concentrations. Egg production rates were often two to four times higher than any previously reported at similar temperatures. Estimates of egg production rates of populations were most closely related to the proportion of reproductively mature females (as measured by a gonad stage index) and female size. Specifically, the gonad stage index (proportion of females capable of spawning) was correlated with the proportion of females that spawned during 24-h incubations, and female size determined the clutch size (i.e., number of eggs produced). Although there were detectable effects of food and temperature on egg production rates, they were generally weaker than the effect of female gonad maturity. Thus, over the broad spatial and temporal scales of this study, the reproductive (i.e., life history) status of a population was more important in determining its egg production rate than direct external factors (i.e., temperature and food conditions).

Egg production rates of Calanus finmarchicus in the Northwest Atlantic (Labrador Sea)

1997 ◽  
Vol 54 (6) ◽  
pp. 1270-1279 ◽  
Author(s):  
J Cabal ◽  
L R Harris ◽  
EJH Head
Keyword(s):  
Egg Production ◽  
Population Characteristics ◽  
Calanus Finmarchicus ◽  
Labrador Sea ◽  
Production Rates ◽  
In Situ Conditions ◽  
Different Types ◽  
Series Of Experiments

Egg production rates and population characteristics of Calanus finmarchicus were examined in the Labrador Sea during the spring of 1994. Several experiments were conducted in order to compare egg production rates and clutch size using different types of container and in the presence and absence of food. In one series of experiments, individual females were incubated either in petri dishes or in polycarbonate bottles (80 mL) in filtered seawater. In these experiments, clutch sizes and egg production rates were not significantly different. In a second series of experiments, groups of 20 females were placed in containers under three sets of conditions: in the presence of food and with a screen to separate copepods from their eggs (FSCREEN), in the presence of food without a screen (FOOD), and in filtered seawater without a screen (FSW). Average egg production rates of female C. finmarchicus were significantly higher in the FSCREEN treatments than in either of the other two. In these experiments, egg production rates were not obviously related to ingestion rates, and these in vitro observations together with observations of in situ conditions suggest that stored reserves may have been used to fuel, or supplement, reproduction in C. finmarchicus in this area.

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
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