scholarly journals Copepod Production in Warm, Oil Polluted Environment: A Laboratory Investigation of Temora stylifera (Dana, 1849) Adapted to the Gulf of Guinea

Author(s):  
Delove Asiedu ◽  
Emmanuel Acheampong ◽  
Noble Asare

Abstract Recent studies suggests that sea surface warming, evidently caused by greenhouse gas emissions, magnifies the toxicity of petroleum hydrocarbons on marine copepods. We assessed this understanding using Temora stylifera, a calanoid copepod common in the Atlantic Ocean and its surrounding waters, as a case study. The copepod was exposed to moderate (0.2 μg.l-1) and high levels (2.0 μg.l-1) of pyrene under three warming scenarios: (i) a no warming control at 28 °C, the surface temperature of the Gulf of Guinea during stable hydrographic period, (ii) moderate warming (+2 °C) and (iii) severe warming (+4 °C) above the control. Food ingestion rate of the copepod increased with warming without significant effect from the pollutant. Feacal pellet production rate (FP) increased by about 86% when the animal was exposed to moderate warming and pyrene at the same time, signifying reduced assimilation of food ingested in these conditions. Lowest FP (3.5 ± 1.1 copepod-1.day-1) indicating increased food assimilation occurred when the stressors were presented either alone or together. Egg production rate and efficiency of the copepod were impacted by only warming, decreasing by ≈60% under both warming scenarios, consistent with previous observations. Mortality rate increased by ≈ 40 % when pyrene pollution was elevated from nought to the highest level. It did not change significantly with temperature, suggesting warming did not exacerbate the lethal effect of pyrene to T. stylifera. These results are contrary to observations on other copepods and highlight the unique responses of Temora to sea surface warming and petroleum pollution.

2019 ◽  
Vol 41 (5) ◽  
pp. 741-758 ◽  
Author(s):  
Josephine GrØnning ◽  
Nam X Doan ◽  
Nguyet T Dinh ◽  
Khuong V Dinh ◽  
Torkel Gissel Nielsen

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.


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

2001 ◽  
Vol 58 (4) ◽  
pp. 647-658 ◽  
Author(s):  
Stéphane Plourde ◽  
Pierre Joly ◽  
Jeffrey A Runge ◽  
Bruno Zakardjian ◽  
Julian J Dodson

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.


2016 ◽  
Vol 19 (1-2) ◽  
pp. 18-23
Author(s):  
H Khatun ◽  
MN Islam ◽  
AA Bhuyan ◽  
MN Hasan ◽  
MS Islam

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


1963 ◽  
Vol 60 (2) ◽  
pp. 225-227
Author(s):  
J. C. M. Trail

Data on egg production, egg weight, food consumption, broodiness, mortality and body weights of the progeny of indigenous poultry of Uganda crossed with Light Sussex, White Leghorn, Rhode Island Red and Black Australorp breeds were collected collected over the 25-week period from 161 to 336 days of age and compared with the performances of indigenous poultry.In comparison with the indigenous birds, the cross-breeds had a 61% higher mean egg production rate, a 34% lower food consumption per pound of eggs produced, a 15% higher egg weight, a 30% reduction in mortality, a 23% increase in body weight and a decrease in broodiness.All the cross-breeds were superior in productive respects to the indigenous birds and the White Leghorn and Light Sussex breeds appeared to be the best for use in the upgrading of indigenous stock for highest egg production results.


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