Among-Population Variability of Fish Growth: II. Influence of Prey Type.

1989 ◽  
Vol 46 (3) ◽  
pp. 468-482 ◽  
Author(s):  
D. Boisclair ◽  
W. C. Leggett
Keyword(s):  
Growth Rates ◽  
Prey Size ◽  
Prey Type ◽  
Growth Efficiency ◽  
Population Variability ◽  
Fish Growth ◽  
Percent Contribution ◽  
The Mean ◽  
Taxonomic Groups ◽  
The Relationship

We tested the significance of the relationship between in situ growth and several diet descriptors using 12 yellow perch (Perca flavescens) populations that varied widely in growth rates. In addition, we tested the assumption of optimal foraging theory that mean prey size is an important regulator of fish growth. The percent contribution of four prey taxonomic groups and six prey size–classes (alone or combined with food consumption estimates) explained between 41 and 95% of among-population variability in growth rates or growth efficiency. We found no significant relationship between growth rates or growth efficiency and mean prey weight. We observed a pattern suggesting the existence of an optimal prey size for (1 mg dry weight) age I + and age II + fish, when the percent contribution of specific prey taxonomic groups or size–classes to the diet was assessed. This pattern was not apparent in the relationship between growth and the mean weight of prey consumed. The energetic advantage of feeding on a given prey type is believed to be related to its low cost/benefit ratio while foraging. Our data indicate that interactions between prey availability (index of searching component of foraging cost) and prey size (index of handling component of foraging cost) are more effectively represented by the percent contribution of a given prey type to the diet than by the mean weight of prey consumed. Our analyses lead us to conclude that the probability of deriving broadly applicable models explaining among-population variability in fish growth rates based on mean prey weight is very low.

Among-Population Variability of Fish Growth: I. Influence of the Quantity of Food Consumed

1989 ◽  
Vol 46 (3) ◽  
pp. 457-467 ◽  
Author(s):  
D. Boisclair ◽  
W. C. Leggett
Keyword(s):  
Water Temperature ◽  
Food Consumption ◽  
Growth Rates ◽  
Yellow Perch ◽  
Prey Availability ◽  
Significant Proportion ◽  
Prey Type ◽  
Population Variability ◽  
Fish Growth ◽  
Growth Variability

We assessed the relationship between in situ fish growth and food consumption for a series of yellow perch (Perca flavescens) populations that exhibited a 1.8 to 10-fold range in growth rates on a weight basis. Perch from 12 populations (lakes) and three year–classes (I +, II +, and III +) were sampled at 3–4 wk intervals from late May to late September 1985. On each occasion, water temperature profile and daily ration were determined. Among-lake water temperature differences were minimal (of the 12 lakes studied 10 had mean water temperatures of 19.0 ± 1 °C) and could not explain growth differences. Food consumption covered a four-fold range within each age–class and varied significantly among populations but not among age–classes. Food consumption explained a significant proportion of among-population variability in perch growth rates only for age I + fish (r2 = 0.52). We argue that other factors such as prey type, prey availability, and fish community descriptors are important determinants of among-population growth variability in the lakes we studied, and by implication, in other systems.

Among-Population Variability of Fish Growth: III. Influence of Fish Community

1989 ◽  
Vol 46 (9) ◽  
pp. 1539-1550 ◽  
Author(s):  
D. Boisclair ◽  
W. C. Leggett
Keyword(s):  
Growth Rates ◽  
Yellow Perch ◽  
Fish Community ◽  
Negative Relationship ◽  
Average Density ◽  
Population Variability ◽  
Fish Growth ◽  
Taxonomic Groups ◽  
Food Consumed

We assessed the relationship between in situ fish growth and fish community descriptors in 12 yellow perch (Perca flavescens) populations that exhibited a 1.8 to 10-fold range in growth rates depending on age class. Data on the quantity and quality of food consumed were used to assess the mechanisms by which fish community composition influences in situ growth rates. Among-population variability in growth rates of the 12 perch populations was most strongly and consistently explained by the average density of the total fish community and/or the average density of cyprinids. A multivariate model involving fish average density and perch feeding levels explained 90% of the variance in perch growth. Perch growth rates decreased as fish average density increased (r2 = 0.60) and increased as feeding levels increased (r2 = 0.30). We found no significant relationship between the quantity of food consumed by perch and fish average density. The percent contribution of prey taxonomic groups to perch diet was not related to fish average density. We suggest that nonexploitative interactions (operating through increased activity costs) provides a more credible explanation for the negative relationship between perch growth and fish average density than does exploitative competition (decreased total quantities of food consumed or prey quality).

scholarly journals Effects of temperature on individual growth rate and body size of a freshwater amphipod

1998 ◽  
Vol 76 (6) ◽  
pp. 1107-1116 ◽  
Author(s):  
Vadim E Panov ◽  
Donald J McQueen
Keyword(s):  
Growth Rates ◽  
Negative Relationship ◽  
Maximum Size ◽  
Growth Efficiency ◽  
Individual Growth ◽  
Summer Temperatures ◽  
Individual Growth Rate ◽  
Natural Temperature ◽  
Effects Of Temperature ◽  
The Relationship

Individual growth rates of the freshwater amphipod Hyalella azteca (Saussure) were measured in the littoral zone oftwo small oligotrophic Ontario lakes and in growth experiments over a natural temperature gradient (10, 15, 20, and 238C).Field observations showed that a temperature of 208C is important for both the induction and termination of reproductiveresting stages in H. azteca. Growth rates were more affected by temperature in small than in large individuals. Growthparameters are related to rearing temperature by linear regressions, which can be used as a simple model for bioenergeticscalculations in crustaceans. A negative relationship between water temperature and maximum size attained by the amphipodswas found. The largest adults were absent in studied populations when summer temperatures were high, and this phenomenon,which has also been observed in other aquatic invertebrates, was bioenergetically determined. Energy-budget estimationsshowed negative net growth efficiency (K2) in the largest adults at temperatures above 208C. The relationship between K2andtemperature showed a dome-shaped pattern, K2values for larger amphipods being maximal at lower temperatures. Seasonalmigrations of adult H. azteca from shallow littoral to deeper cold habitats, observed in lakes during the warmest periods, appearto be temperature-induced and bioenergetically advantageous, despite probable increases in predation risk experienced inspatially simple deep-water habitats.

The Relationship Between Prey Size and Handling Time and Prey Size and Capture Success in 3 Sympatric Species of Dasyurid Marsupials

1988 ◽  
Vol 15 (6) ◽  
pp. 615 ◽  
Author(s):  
MC Calver ◽  
JS Bradley ◽  
DR King
Keyword(s):  
Linear Regression ◽  
Prey Size ◽  
Handling Time ◽  
Prey Type ◽  
Sympatric Species ◽  
Niche Separation ◽  
Simple Linear Regression ◽  
Predator Species ◽  
The Relationship ◽  
Better Than

Regressions of handling time on prey weight were determined for the dasyurids Srninthopsis hirtipes, S. ooldea and Ningaui spp. preying on grasshoppers and cockroaches in the laboratory. In all cases, a simple linear regression fitted the relationships better than logarithmic models. The slopes of the regression lines were steeper for grasshopper prey than for cockroach prey in all species, and for each prey type the slopes for the predators were ranked in order of predator weight. Capture efficiency, defined as the proportion of successful attacks, did not vary significantly between predator species and prey types, and all predators showed declining capture efficiencies with increasing prey size. Niche separation in these dasyurids does not appear to be based on different optimal prey sizes for each species.

Estimation of Recent Growth of Field-Caught Postlarval American Lobsters, Homarus americanus, from RNA:DNA Ratios

1994 ◽  
Vol 51 (2) ◽  
pp. 286-294 ◽  
Author(s):  
Marie Antonette R. Juinio ◽  
J. Stanley Cobb
Keyword(s):  
Growth Rates ◽  
Food Limitation ◽  
Homarus Americanus ◽  
Zooplankton Biomass ◽  
Individual Growth ◽  
Prolonged Duration ◽  
The Mean ◽  
Temperature And Growth ◽  
Relationship Of ◽  
The Relationship

We developed a growth model for the postlarvae of the American lobster, Homarus americanus, using the relationship of RNA:DNA ratios, temperature, and growth rates during postmolt through early pre-molt of laboratory-reared postlarval lobsters. The model was used to estimate individual growth rates of 385 postlarval lobsters in molt stages C and D0, collected at two sites in Block Island Sound over three years, 1988–90. The mean growth rates of postlarvae collected in June 1989 and 1990 (0.57 ± 0.19 and 0.54 ± 0.18 mg protein∙d−1) were significantly higher than those collected in July (0.39 ± 0.17 and 0.43 ± 0.18 mg protein∙d−1). Changes in sea surface temperatures of zooplankton biomass did not account for the seasonal difference in growth rates, nor was there correlation between the biweekly mean growth rates and postlarval densities. The incidence of poorly nourished postlarval lobsters (individuals with growth rates < 0.22 mg protein∙d−1) was less than 10% of the total samples in each year. We found no evidence that food limitation, resulting in starvation or prolonged duration of the postlarval instar, was a significant factor contributing to the observed interannual variability of postlarval densities.

Migration as a source of bias in the measurement of cephalopod growth

1994 ◽  
Vol 6 (2) ◽  
pp. 179-184 ◽  
Author(s):  
Emma M.C. Hatfield ◽  
Paul G. Rodhouse
Keyword(s):  
Growth Rates ◽  
Time Interval ◽  
Elapsed Time ◽  
The Mean ◽  
Sampling Biases ◽  
June July ◽  
The Relationship ◽  
Modal Group ◽  
Daily Time

Theory predicts that, in a closed exploited population showing no sampling or other bias, the mean age of fish or squid between one sampling date and the next should increase by the time interval between samples. Age data, derived from statoliths, have been used to test the hypothesis that the effect of migration through an area where a population of Loligo gahi is sampled would be apparent as an increase in mean age per modal group of less than one day per daily time interval between samples. The data show that, in both females and males, the relationship between mean statolith increment number and elapsed time between samples is positive in some months and negative in others. The months in which the relationship between mean increment number and elapsed time is negative are similar to those months in which recruitment has previously been demonstrated to occur, in February, April/May and September for both females and males. Cohorts of squid remain available to the fishery from June–September (females) and February–May and June–July (males) thus allowing mean monthly growth rates of 0.4 mm d−1 for females and 0.7 mm d−1 for males to be calculated. The present study shows that putative age data derived from statoliths apparently demonstrate some sampling biases within a fishery and their effects on the measurement of growth. Migration through the sampled population is manifested by an increase in mean increment number of less than one per day between samples, and growth can only be assessed where the increase in mean increment number is not significantly different from the time elapsed between samples.

Are Growth Parameters Estimated from Tagging and Age–Length Data Comparable?

1988 ◽  
Vol 45 (6) ◽  
pp. 936-942 ◽  
Author(s):  
R. I. C. C. Francis
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Growth Parameters ◽  
Growth Models ◽  
Maximum Length ◽  
Fish Growth ◽  
Data Sets ◽  
Von Bertalanffy ◽  
Length Data ◽  
The Mean

The two most common ways of estimating fish growth use age–length data and tagging data. It is shown that growth parameters estimated from these two types of data have different meanings and thus are not directly comparable. In particular, the von Bertalanffy parameter l∞ means asymptotic mean length at age for age–length data, and maximum length for tagging data, when estimated by conventional methods. New parameterizations are given for the von Bertalanffy equation which avoid this ambiguity and better represent the growth information in the two types of data. The comparison between growth estimates from these data sets is shown to be equivalent to comparing the mean growth rate of fish of a given age with that of fish of length equal to the mean length at that age. How much these growth rates may differ in real populations remains unresolved: estimates for two species of fish produced markedly different results, neither of which could be reproduced using growth models. Existing growth models are shown to be inadequate to answer this question.

Mitotic-cycle time and the development of embryo and endosperm in compatible and incompatible crosses in tuber-bearing Solanum species

Genome ◽  
2001 ◽  
Vol 44 (3) ◽  
pp. 426-431 ◽  
Author(s):  
R W Masuelli
Keyword(s):  
Growth Rates ◽  
Doubling Time ◽  
Mitotic Cycle ◽  
Solanum Species ◽  
Endosperm Balance Number ◽  
Solanum Commersonii ◽  
Cell Doubling Time ◽  
The Mean ◽  
The Relationship ◽  
Solanum Spp

To understand the relationship between early seed development and the EBN (endosperm balance number) hypothesis, the embryo and endosperm growth rates in crosses among Solanum spp. with the same and different EBNs were analyzed. For the embryo, the differences in the mean cell-doubling time (MCDT) between the compatible species 2x Solanum gourlayi and Solanum acaule was 3.9 h, whereas the incompatible species Solanum commersonii had MCDT differences of 10 and 13.9 h with 2x S. gourlayi and S. acaule, respectively. The embryo growth rates of the 2EBN species S. acaule and S. gourlayi were almost twice as fast as that of the 1EBN species S. commersonii. Nuclei of variable sizes were observed in the endosperms resulting from incompatible crosses. The author discusses the possibility that the collapse of the endosperm in inter-EBN crosses could be caused by differences in the MCDT between the parents that produce hybrid endosperms with high levels of DNA synthesis and transcription activity, resulting in increased nuclear size. A model is proposed to explain the formation of enlarged endosperm nuclei in incompatible crosses in the genus Solanum.Key words: mean cell-doubling time, endosperm balance number, Solanum, endosperm, embryo.

Energy Dynamics of Two Benthic Crustaceans in Relation to Diet

1976 ◽  
Vol 33 (11) ◽  
pp. 2544-2550 ◽  
Author(s):  
J. J. Swiss ◽  
M. G. Johnson
Keyword(s):  
Algal Species ◽  
Growth Efficiency ◽  
Caloric Content ◽  
Chlorella Ellipsoidea ◽  
Energy Dynamics ◽  
Ankistrodesmus Falcatus ◽  
Scenedesmus Dimorphus ◽  
Growth Production ◽  
Taxonomic Groups ◽  
The Relationship

Energy dynamics were studied in Asellus racovitzai (Crustacea: Isopoda) and Gammarus fasciatus (Crustacea: Amphipoda) fed various selected algal species (Cyanophyta — Oscillatoria sp., Anabaena flos-aquae, Anacystis nidulans, Microcystis aeruginosa; Chorophyta — Chlorella ellipsoidea, Scenedesmus dimorphus, Ankistrodesmus falcatus) and lake sediments. Calculations of growth, production, assimilation, and growth efficiency were made from measurements of weight change, respiration rate, and caloric content of experimental animals. Although growth rate, production, and growth efficiency were often highest in animals fed green algae, differences were not attributable solely to green vs. blue-green taxonomic groups. The relationship between assimilation rate and growth efficiency was examined, and the possible consequences of lower values of assimilation were discussed in terms of delayed development to maturity and reproduction.

Multi-Center Calibration of the Second Reference Material for Thromboplastin, Rabbit, Plain, Coded CRM 149R

1991 ◽  
Vol 65 (03) ◽  
pp. 263-267 ◽  
Author(s):  
A M H P van den Besselaar ◽  
R M Bertina
Keyword(s):  
Reference Material ◽  
Standard Error ◽  
Standard Errors ◽  
Sensitivity Index ◽  
Long Term Stability ◽  
Significant Bias ◽  
The Mean ◽  
The Relationship ◽  
International Sensitivity Index

SummaryIn a collaborative trial of eleven laboratories which was performed mainly within the framework of the European Community Bureau of Reference (BCR), a second reference material for thromboplastin, rabbit, plain, was calibrated against its predecessor RBT/79. This second reference material (coded CRM 149R) has a mean International Sensitivity Index (ISI) of 1.343 with a standard error of the mean of 0.035. The standard error of the ISI was determined by combination of the standard errors of the ISI of RBT/79 and the slope of the calibration line in this trial.The BCR reference material for thromboplastin, human, plain (coded BCT/099) was also included in this trial for assessment of the long-term stability of the relationship with RBT/79. The results indicated that this relationship has not changed over a period of 8 years. The interlaboratory variation of the slope of the relationship between CRM 149R and RBT/79 was significantly lower than the variation of the slope of the relationship between BCT/099 and RBT/79. In addition to the manual technique, a semi-automatic coagulometer according to Schnitger & Gross was used to determine prothrombin times with CRM 149R. The mean ISI of CRM 149R was not affected by replacement of the manual technique by this particular coagulometer.Two lyophilized plasmas were included in this trial. The mean slope of relationship between RBT/79 and CRM 149R based on the two lyophilized plasmas was the same as the corresponding slope based on fresh plasmas. Tlowever, the mean slope of relationship between RBT/79 and BCT/099 based on the two lyophilized plasmas was 4.9% higher than the mean slope based on fresh plasmas. Thus, the use of these lyophilized plasmas induced a small but significant bias in the slope of relationship between these thromboplastins of different species.

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