Comparison of Actual and Potential Growth Rates of Brown Trout (Salmo trutta) in Natural Streams Based on Bioenergetic Models

1989 ◽  
Vol 46 (6) ◽  
pp. 1067-1076 ◽  
Author(s):  
Richard J. Preall ◽  
Neil H. Ringler

A ratio of specific growth rate to predicted maximum growth rate was employed as an ecological growth coefficient (EGC) in identifying major determinants of growth for brown trout, Salmo trutta, in natural streams. The coefficient may be more useful than specific growth rate when comparing trout populations from streams having diverse characteristics, since it accounts for the quantitative effects of stream temperature and mean trout weight. The maximum growth rate was generated by translating Elliott's bioenergetic equations into computer models applicable to fish weighing 5–300 g and to stream temperatures of 3.8–21.7 °C. EQMAX is the simpler model and generates only maximum growth rate. TROUT estimates the maximum ration size, maximum growth rate, and a variety of bioenergetic parameters. The EGC for Age I + trout ranged from 60 to 90% in three central New York streams. A relatively low EGC (30–60%) observed for Age II + trout in one stream may have been due to the inefficiency of feeding on small invertebrates. Temperature appears to be a dominant feature governing trout growth in streams. The bioenergetic models may provide useful predictions of the effects of foraging on prey communities by brown trout.

2018 ◽  
Vol 210 ◽  
pp. 04044
Author(s):  
Juan Carlos Beltrán-Prieto ◽  
Long Huynh Bach Son Nguyen

Haldane equation is a mathematical expression that has been widely used in growth kinetics to give a proper fit to experimental data in case of substrate inhibition during enzymatic processes. It determines the specific growth rate of a microorganism based on the substrate concentration, the half saturation constant, the inhibitory constant and the maximum growth rate achievable. However, for practical and experimental design purposes it is important to describe Haldane equation in terms of the initial concentration of substrate, since this information is required to know the proper amount of initial substrate to be used. For this reason, in the present paper we proposed to integrate the expression of yield factor and the definition of specific growth rate in a batch system into Haldane’s equation and to solve analytically the mathematical equations in order to obtain a final expression that correlates the maximum growth rate, the limiting nutrient concentration at which the specific growth is half its maximum value, the inhibitory constant, the initial concentration of substrate and the initial amount of biomass required in time. Accordingly, simulation and numerical studies are presented to analyze and discuss the importance of the obtained model.


2015 ◽  
Vol 754-755 ◽  
pp. 1076-1080
Author(s):  
Sharul Aida Mohd Shayuti ◽  
Shi Fern Chong ◽  
Zarina Zakaria ◽  
Dachyar Arbain ◽  
Noorulnajwa Diyana Yaacob

A study was conducted to determine the most optimal preservation technique for P. sajor-caju spawns which produce maximum specific growth rate and shortest doubling time by using contois kinetic model. The analyzed experimental data showed that lyophilized P. sajor-caju spawn showed the highest maximum specific growth rate, and shortest doubling time compared to cryopreserved P. sajor-caju spawn and 4oC stored P. spawn. There was no significant difference in aspect of growth rate between the lyophilization and cryopreservation techniques which were; 0.148 (μmax)/ (g/day) and 0.147(μmax)/ (g/day) respectively. Based on the result, lyophilization technique was considered as the best preservation technique for preserving P. sajor-caju spawn due to high maximum growth rate which indicates high survival after exposure to preservation treatment.


1946 ◽  
Vol 22 (3-4) ◽  
pp. 118-129
Author(s):  
MARGARET E. BROWN

1. Groups of trout fry of the same parentage were grown in environments where the following factors were controlled: temperature, amount and intensity of illumination, rate of water flow, aeration and chemical composition of the water, amount of living space and quality of food supply. They were allowed to eat as much as they would, and individual weights were recorded during the first 8 months after the beginning of feeding. 2. There was soon an increase in the range of individual weight in each group of fry, and thereafter the larger fry grew faster than smaller ones. When the larger fry were removed, the smaller ones grew at an increased specific rate, and when larger fry were added, the smaller ones grew more slowly. It is suggested that a ‘size hierarchy’ was established within each group, and an individual's specific growth rate depended on its position in the order of decreasing weight. 3. There was an optimum degree of crowding for maximum productivity. Compared with the fry in this group, the specific growth rates of individuals in larger, more crowded groups depended on the number of fish of larger size, while in smaller, less crowded groups, individuals grew at rates depending on the proportion of fish which were larger and smaller. 4. Alevin weight had little effect on the specific growth rates of fry. 5. There were differences between the growth histories of fry derived from alevins of the same weight and descended from the same father but different mothers (all of the same stock, age and size). 6. The specific growth rates decreased as the fry grew older, but there was no correlation between body weight and specific growth rate, except for the size hierarchy effect within each group. This effect had a greater influence on the size of individual fry than had either alevin weight or heredity.


1961 ◽  
Vol 38 (3) ◽  
pp. 595-604
Author(s):  
D. R. SWIFT

1. A regular annual growth-rate cycle is demonstrated in wild and hatchery yearling brown trout; the fish have a high growth rate in the spring and autumn and a low growth rate during the summer and winter of each year. 2. Experimental work with constant-environment aquaria, together with the results of the field work, indicate that the water temperature is the main external environmental factor influencing the growth rate. Maximum growth rate is achieved at 12° C. 3. The reason for the fall in growth rate above 12° C. is discussed and it is suggested that inadequacy of the respiratory system of the fish is the prime cause.


1955 ◽  
Vol 32 (4) ◽  
pp. 751-764
Author(s):  
D. R. SWIFT

1. Seasonal variations in the growth rate, food reserves and activity of the thyroid gland of hatchery-reared brown trout have been investigated. 2. Two peaks of maximum growth rate were found, in spring and autumn. A marked depression of rate occurred during midsummer and winter. 3. Fat which was laid down along the mesenteries and pyloric caecae was found to be the main food reserve. Glycogen was found in small quantities in the liver and muscle. The composition of the muscle and liver was constant except for an autumnal fall in the female liver glycogen level. The fat reserves reached a peak of 23% by weight of the gut wall during July then fell to 5% in autumn. 4. Maturation of the gonads commenced in females in June and in males in July and was completed during October. The protein content of the ovary increased by 16%, and of the testis by 10%. The fat content of the ovary increased by 3%. 5. A new method is described for the determination of thyroid activity in fish using radioactive iodine. Peak thyroid activity was found to occur in midsummer.


2012 ◽  
Vol 69 (5) ◽  
pp. 821-832 ◽  
Author(s):  
Irene Parra ◽  
Ana Almodóvar ◽  
Daniel Ayllón ◽  
Graciela G. Nicola ◽  
Benigno Elvira

This study looks at the relative influence of water temperature and density dependence on the spatial variation in body size of 126 brown trout ( Salmo trutta ) cohorts from 12 Iberian rivers over a 12-year period. Mean cohort mass and length of age groups 0+ to 2+ varied significantly among sampling sites because of the concurrent effect of water temperature and density dependence. Density in suitable habitat had a limiting role that influenced potential maximum growth of cohorts, and water temperature differentiated these cohorts in two groups of sites with high and low potential maximum growth. Water temperature had a positive cumulative effect on body size of all age classes. However, body size of age-0 trout was nonlinearly influenced by short-term exposure to extreme water temperature. Thus, extremely high temperatures became a limiting factor and had deleterious effects on growth. There were intracohort and intercohort effects of density dependence throughout the life span, which were mainly due to the density in the available suitable habitat of trout of the same age or older. The present study supports the hypothesis that both density-dependent and density-independent processes are crucial for the understanding of population dynamics and that their relative importance varies across scales of space and time.


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