Food Availability as a Proximate Factor Influencing Individual Growth Rates in the Iguanid Lizard Sceloporus Merriami

Ecology ◽  
1978 ◽  
Vol 59 (4) ◽  
pp. 770-778 ◽  
Author(s):  
Arthur E. Dunham
Keyword(s):  
Food Availability ◽  
Growth Rates ◽  
Individual Growth ◽  
Proximate Factor

A Bioenergetics Model of Zebra Mussel, Dreissena polymorpha, Growth in the Great Lakes

1992 ◽  
Vol 49 (7) ◽  
pp. 1406-1416 ◽  
Author(s):  
Daniel W. Schneider
Keyword(s):  
Great Lakes ◽  
Food Availability ◽  
Growth Rates ◽  
Zebra Mussel ◽  
Dreissena Polymorpha ◽  
Lake Superior ◽  
Zebra Mussels ◽  
Growth Patterns ◽  
Individual Growth ◽  
Main Body

An individual growth model of the zebra mussel, Dreissena polymorpha, is presented, based on weight- and temperature-specific physiological parameters taken from the literature on zebra mussels and marine mussels. Given food availability and water temperature the model can predict growth and consumption of zebra mussels in diverse environments. The model was tested with data from Lake Constance and matches observed growth fairly closely. Using the functional response of zebra mussels to increasing food concentration, the model simulates individual zebra mussel growth in novel habitats. For the Great Lakes, the following predictions were made: zebra mussels have bimodal growth patterns, with rapid growth in the spring and fall during periods of high food availability and moderate temperatures; growth rates are highest in Lake Ontario and lowest in Lake Superior, reflecting the trophic gradient in the Great Lakes; based on published weight/fecundity relationships, zebra mussels reach reproductive size in all of the Great Lakes except the main body of Lake Superior; and local eutrophication (e.g. Duluth/Superior Harbor) increases zebra mussel growth rates. Modelled consumption rates in Lakes Erie and Ontario are also consistent with rates of consumption by the zebra mussel in eutrophic and mesotrophic European lakes.

Geostatistically modeling stem size and increment in an old-growth forest

1994 ◽  
Vol 24 (7) ◽  
pp. 1354-1368 ◽  
Author(s):  
Franco Biondi ◽  
Donald E. Myers ◽  
Charles C. Avery
Keyword(s):  
Spatial Patterns ◽  
Growth Rates ◽  
Spatial Dependence ◽  
Basal Area ◽  
Tree Density ◽  
Individual Growth ◽  
Old Growth ◽  
Model Estimate ◽  
Stem Size ◽  
Old Growth Forest

Geostatistics provides tools to model, estimate, map, and eventually predict spatial patterns of tree size and growth. Variogram models and kriged maps were used to study spatial dependence of stem diameter (DBH), basal area (BA), and 10-year periodic basal area increment (BAI) in an old-growth forest stand. Temporal variation of spatial patterns was evaluated by fitting spatial stochastic models at 10-year intervals, from 1920 to 1990. The study area was a naturally seeded stand of southwestern ponderosa pine (Pinusponderosa Dougl. ex Laws. var. scopulorum) where total BA and tree density have steadily increased over the last decades. Our objective was to determine if increased stand density simply reduced individual growth rates or if it also altered spatial interactions among trees. Despite increased crowding, stem size maintained the same type of spatial dependence from 1920 to 1990. An isotropic Gaussian variogram was the model of choice to represent spatial dependence at all times. Stem size was spatially autocorrelated over distances no greater than 30 m, a measure of average patch diameter in this forest ecosystem. Because patch diameter remained constant through time, tree density increased by increasing the number of pine groups, not their horizontal dimension. Spatial dependence of stem size (DBH and BA) was always much greater and decreased less through time than that of stem increment (BAI). Spatial dependence of BAI was close to zero in the most recent decade, indicating that growth rates in 1980–1990 varied regardless of mutual tree position. Increased tree crowding corresponded not only to lower average and variance of individual growth rates, but also to reduced spatial dependence of BAI. Because growth variation was less affected by intertree distance with greater local crowding, prediction of individual growth rates benefits from information on horizontal stand structure only if tree density does not exceed threshold values. Simulation models and area estimates of tree performance in old-growth forests may be improved by including geostatistical components to summarize ecological spatial dependence.

Wintertime growth in Atlantic salmon under changing climate: the importance of ice cover for individual growth dynamics

2021 ◽  
Author(s):  
Laura Härkönen ◽  
Pauliina Louhi ◽  
Riina Huusko ◽  
Ari Huusko
Keyword(s):  
Climate Change ◽  
Atlantic Salmon ◽  
Growth Rates ◽  
Growth Dynamics ◽  
Ice Cover ◽  
Individual Growth ◽  
Late Winter ◽  
Dynamic Nature ◽  
Individual Level ◽  
Growth Variation

Understanding the dynamic nature of individual growth in stream-dwelling salmonids may help forecast consequences of climate change on northern fish populations. Here, we performed an experimental capture-mark-recapture study in Atlantic salmon to quantify factors influencing wintertime growth variation among juveniles under different scenarios for ice cover reduction. We applied multiple imputation to simulate missing size observations for unrecaptured fish, and to account for individual-level variation in growth rates. The salmon parr exhibited substantial body length shrinkage in early winter, suppressed growth through mid-winter, and increasing growth rates in late winter and particularly in spring. Unexpectedly, the presence of ice cover had no direct effects on wintertime growth. Instead, our results implied increasing energetic costs with reducing ice cover: individuals exposed to absent or shortened ice-covered period gained mass at a lowered rate in spring whereas the present, long ice-covered period was followed by rapid growth. This study emphasizes natural resilience of Atlantic salmon to wintertime environmental variation which may help the species to cope with the reductions in ice cover duration due to climate change.

Mangroves as Fish Habitat

2015 ◽  
Keyword(s):  
Growth Rates ◽  
Fish Habitat ◽  
Individual Growth ◽  
Baja California Sur ◽  
Bivalve Species ◽  
Anthropogenic Pressures ◽  
La Paz ◽  
Frequency Distributions ◽  
Mass Increment ◽  
Secondary Productivity

<em>Abstract</em>.—To measure secondary productivity of mangrove systems, we estimated the abundance (individuals/m<sup>2</sup>) and mass increment (g/month) of the two bivalve species: the black ark <em>Anadara tuberculosa </em>and palmate oyster <em>Saccostrea palmula</em>. Mass increments were based on individual growth rates derived from length-frequency distributions analyses. Samples were collected at three mangrove estuaries in a sand barrier at Ensenada de La Paz from August 2007 to July 2009. The average abundance was 1.27 individuals/m<sup>2</sup> for black ark and 510 individuals/m<sup>2</sup> for palmate oysters. Estimated growth rates were 3.67 g/month for black ark and 0.18 g/month for palmate oysters. The average secondary productivity of the black ark was 4.51 g•m<sup>-2</sup>•month<sup>-1</sup> and peaked during the spring, while for the palmate oyster <em>Saccostrea palmula </em>it was 97.9 g•m<sup>-2</sup>•month<sup>-1</sup>, with peak productivity recorded during the summer. The findings of this investigation constitute a necessary element for establishing a baseline to evaluate the consequences of the various natural and anthropogenic pressures that the mangrove systems of El Mogote of La Paz Bay, Baja California Sur, Mexico.

Influence of food abundance on individual behaviour strategy and growth rate in juvenile brown trout (Salmo trutta)

2003 ◽  
Vol 81 (4) ◽  
pp. 684-692 ◽  
Author(s):  
Eva Brännäs ◽  
Sara Jonsson ◽  
Hans Lundqvist
Keyword(s):  
Brown Trout ◽  
Growth Rates ◽  
Salmo Trutta ◽  
Swimming Activity ◽  
Food Abundance ◽  
Individual Growth ◽  
Food Level ◽  
General Tendency ◽  
Brown Trout Salmo Trutta ◽  
Juvenile Brown Trout

We studied the benefit of being territorial as an effect of food abundance by measuring the proportions of individuals that displayed a territorial, floating (individuals occasionally displayed territorial behaviour), or nonterritorial (shoaling) behaviour strategy, and individual growth rates. Also, swimming activity was monitored as an indicator of emigration. Replicate groups of 12 juvenile brown trout (Salmo trutta) were released into an artificial stream channel, fed according to one of four food regimes for 10 days, and allocated to one of three behaviour categories. There was no significant relationship between food abundance and the number of territorial individuals. Instead, the proportions of individuals that displayed the alternative behaviour strategies, i.e., floating and nonterritorial, changed with food abundance. At the lowest food level, more individuals displayed nonterritorial than floating behaviour, but these two strategies were equally represented at the highest food level. The difference in growth rates with respect to behaviour category was highest at intermediate food levels. At the highest and lowest food levels, nonterritorial fish and floaters grew nearly as fast or as poorly, respectively, as the territorial individuals. Swimming activity between the two sections of the stream tank was greatest at the lowest food level, and there was a general tendency (not significant) for the floaters to exhibit the greatest activity.

scholarly journals Size and variation in individual growth rates among food web modules

Ecosphere ◽  
2017 ◽  
Vol 8 (7) ◽  
pp. e01862 ◽  
Author(s):  
Monica Granados ◽  
Ianina Altshuler ◽  
Stéphane Plourde ◽  
Gregor F. Fussmann
Keyword(s):  
Food Web ◽  
Growth Rates ◽  
Individual Growth

Predictability of individual growth rates in tilapia

1993 ◽  
pp. 147-158
Author(s):  
Marietta S. Palada-de Vera ◽  
Ambekar E. Eknath
Keyword(s):  
Growth Rates ◽  
Individual Growth
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