Energy Dynamics of the Eutrophic Chironomid Chironomus plumosus f. semireductus from the Bay of Quinte, Lake Ontario

1980 ◽  
Vol 37 (8) ◽  
pp. 1254-1265 ◽  
Author(s):  
Ora E. Johannsson
Keyword(s):  
Growth Rate ◽  
Feeding Rate ◽  
Assimilation Efficiency ◽  
Growth Efficiency ◽  
Time Of Day ◽  
Organic Content ◽  
Algal Community ◽  
Instantaneous Growth Rate ◽  
Larval Size ◽  
Instantaneous Growth

Relationships between feeding rate, temperature, body size, and time of day were investigated and collated with seasonal assimilation efficiencies of in situ chironomids to construct a picture of chironomid energetics over the year. Temperature controlled feeding rate, and larval size and time of day exerted no effect. The temperature optimum plateaued between 22.0 and 24.5 °C, decreasing logarithmically outside this range. Both assimilation efficiency (AE) and organic content of the food varied seasonally, but were not correlated. Periods of high AE corresponded with the latter part of Melosira or Melosira–Stephanodiscus blooms, while periods of low AE occurred between diatom blooms and during the late summer blue-green bloom. Consequently, growth fluctuated throughout the year, being a result of the interaction of temperature and AE. Anabolic processes dominated at AE greater than 3.5%. Maximum net growth efficiency (NGE) was attained when AE ≥ 6% and temperature ≥ 15 °C. NGE was more sensitive to changes in AE than temperature. Instantaneous growth rate, however, was more sensitive to changes in temperature. Daily ingestion (mg) exceeded body weight by as much as 460–480%, which equals the sediment-processing capacity of freshwater detritivores.Key words: chironomid, feeding rate, assimilation efficiency, instantaneous growth rate, net growth efficiency, algal community, Bay of Quinte

Verification of a Formula for the Growth of Troughs and Wedges

1953 ◽  
Vol 34 (10) ◽  
pp. 441-443
Author(s):  
F. W. Ernst ◽  
Roy L. Fox ◽  
H. E. Hutchison
Keyword(s):  
Growth Rate ◽  
Instantaneous Growth Rate ◽  
Instantaneous Growth ◽  
Strong Asymmetry

A formula for the instantaneous growth rate of vorticity waves was tested on 152 contour troughs and 101 contour wedges at the 500-millibar level. It was found that the formula could be used qualitatively for determining whether individual troughs and wedges will intensify or weaken over periods of 24 hours, without carrying out the laborious computations required by an exact application of the formula. Further examination of data showed that cut-off lows formed in pre-existing troughs most readily when the negative tilt of the troughs was greater than 15°, or strong asymmetry was present.

scholarly journals EFECTO DE LA SALINIDAD SOBRE EL CRECIMIENTO POBLACIONAL Y EL RENDIMIENTO DEL ROTIFERO BRACHIONUS PLICATILIS (CEPA CIENAGA GRANDE DE SANTA MARTA)

2016 ◽  
Vol 22 ◽  
Author(s):  
Adriana Vallejo I. ◽  
Federico Newmark ◽  
María Mercedes Criaies
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Laboratory Experiments ◽  
Doubling Time ◽  
Brachionus Plicatilis ◽  
Growth And Yield ◽  
Instantaneous Growth Rate ◽  
Instantaneous Growth ◽  
Adaptive Capability

The effect of salinity on the population growth and yield of a strain of Brachionus plicatiiis (O.F. Muller, 1786) was determined by two laboratory experiments. The rotifer B. plicatiiis was isolated from the plankton of the Ciénaga Grande de Santa Marta, Colombia, and cultivated in laboratory under different salinity conditions. The local microalgae Chiorella sp., also isolated in laboratory, was used as food for the rotifers. Salinity values ranged from 3 to 24 o/oo in the first experiment and 30 to 45 o/oo in the second. It was found that these rotifers grow and exhibit a" high adaptive capability when cultured at salinities ranging from 16 to 40o/oo. The rotifer curves of population growth were negative at salinities under 16 o/oo. At salinities of 30, 36, and 40 o/oo the maximum densities were similar in the ninth day. Although maximum densities were somewhat lower at 45 o/oo salinity, no significant statistical differences were found. Maximum values of density (d), yield (y), instantaneous growth rate (k) and doubling time (td) corresponded to a salinity of 36o/oo.

Instantaneous Growth Rate of Freshwater Nannochloropsis spp. at Different Salinity Levels

2015 ◽  
Vol 16 (1) ◽  
Author(s):  
Lady Gem H. Maquirang ◽  
Romeo D. Caturao ◽  
Jessy H. Maquirang
Keyword(s):  
Growth Rate ◽  
Cell Density ◽  
Instantaneous Growth Rate ◽  
Nitrogen Levels ◽  
Instantaneous Growth ◽  
Randomized Design ◽  
Significant Difference ◽  
Salinity Levels ◽  
Initial Sampling ◽  
Range Test

A study was conducted to determine the instantaneous growth rate of freshwater Nannochloropsis spp. at five different salinity levels (T1, 0 ppt - control; T2, 5 ppt; T3, 10 ppt; T 4, 15 ppt; and T5, 20 ppt) and were arranged in a Complete Randomized Design (CRD). Nannochloropsis spp. was cultured in fifteen 500 ml plastic experimental bottles based on the assigned treatment for eleven days. Initial sampling was done during the start of the experiment, and everyday thereafter. Cell density was counted using haemacytometer and viewed under the microscope. Results showed that the highest cell density and instantaneous growth rate of freshwater Nannochloropsis spp. was obtained in Treatment 3 with 18,510,000.00 cells/ml and16.00±0.36 cells/ml, respectively, while Treatment 5 had the lowest cell density and growth rate (10,040,833.33 cells/ml; 15.38±0.46 cells/ml).One-way ANOVA and Duncan’s Multiple Range Test revealed there was a significant difference (p<0.05) on the days of culture (days 3, 7 and 8) among treatments. Results for both cell density (cells/ml) and instantaneous growth rate (K) proved that freshwater Nannochloropsis spp. can tolerate a wider range of salinity from 5 ppt to 15 ppt. However, further studies should be conducted at a wider range of salinity levels and other variables such as nitrogen levels and light intensity to have a complete picture of the reproductive biology of this species. Keywords - Aquatic Ecology, instantaneous growth rate, freshwater Nannochloropsis spp., salinity levels, experimental design, Philippines, Asia

Estimation of Fish Production Rates and Associated Variances

1983 ◽  
Vol 40 (10) ◽  
pp. 1729-1736 ◽  
Author(s):  
Raymond M. Newman ◽  
Frank B. Martin
Keyword(s):  
Growth Rate ◽  
Brook Trout ◽  
Standing Stock ◽  
Annual Production ◽  
Salmo Gairdneri ◽  
Instantaneous Growth Rate ◽  
Fish Production ◽  
Production Rates ◽  
Instantaneous Growth ◽  
Production Models

Variance estimators for fish production rates are explicitly derived for two production models: the instantaneous growth rate and increment summation methods. Statistics for standing stock, mean interval standing stock, instantaneous growth rate, and production:mean standing stock [Formula: see text] ratio are presented. The use of a jackknife estimator is proposed for estimating the variance of instantaneous growth rate. Comparison of the results from both production models provides a method of cross-validating results. The use of these statistics is illustrated in example calculations with trout population data. Brook trout (Salvelinus fontinalis) annual production in 1969 was significantly higher than combined annual production of brook trout, brown trout (Salmo trutta), and rainbow trout (Salmo gairdneri) in 1977. Variance estimates are affected by population and mean weight estimates. Validity of the production estimates is based on the validity of model assumptions.

Growth Rate of Central British Columbia Pink Salmon (Oncorhynchus gorbuscha)

1964 ◽  
Vol 21 (5) ◽  
pp. 1101-1128 ◽  
Author(s):  
R. J. LeBrasseur ◽  
R. R. Parker
Keyword(s):  
Growth Rate ◽  
British Columbia ◽  
Pink Salmon ◽  
Growth Period ◽  
Oncorhynchus Gorbuscha ◽  
Instantaneous Growth Rate ◽  
Commercial Fishery ◽  
Instantaneous Rate ◽  
Instantaneous Growth ◽  
Rate Of Increase

Pink salmon were sampled at various stages, as fry and fingerling in enclosed waters, as juveniles and subadults in the ocean and as maturing salmon in the commercial fishery. On the basis of length frequency data and from recapture measurements of marked and tagged individuals the instantaneous growth rate in length (gl) for successive 30-day periods was computed. As a result three major growth stanzas were recognized. Following the entrance of fry into the estuary, growth was approximately exponential (gl = 0.559) during an initial 40-day period. Fish increased in length from 3.5 to 8.4 cm. Thereafter, the instantaneous rate of growth gradually declined to a minimum in March (gl = 0.076). During this time the length increased from 8.4 to 32.5 cm. The final growth period was marked by a rapid rate of increase in length in late April and early May (gl = 0.171), followed by a declining rate of increase in length which was finally terminated after the fish had re-entered the coastal waters and the commercial fishery (gl = 0.041). The length data were transformed to weight data from a generalized length–weight regression. During the initial 30-day period the instantaneous growth rate in weight, gw = 6.53. From a value of gw = 2.87 for late May and early June the instantaneous growth rate progressively fell to a low of gw = 1.28 for late March to early April. During late April to early May of the ultimate year, gw = 1.74. The instantaneous growth rate then fell to gw = 1.14 during mid July to early August. It was concluded that growth, in length and weight, of central British Columbia pink salmon is a continuing process with no period of complete cessation from the time the fry enter the sea until the time they re-enter the estuary as adults.

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