scholarly journals Effect of food abundance on aggressiveness and territory size of juvenile rainbow trout, Oncorhynchus mykiss

2013 ◽  
Vol 85 (1) ◽  
pp. 241-246 ◽  
Author(s):  
Asra Toobaie ◽  
James W.A. Grant
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Food Abundance ◽  
Territory Size ◽  
Juvenile Rainbow Trout ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Effect Of Food

scholarly journals Population density and territory size in juvenile rainbow trout, Oncorhynchus mykiss: implications for population regulation

2012 ◽  
Vol 69 (6) ◽  
pp. 1121-1128 ◽  
Author(s):  
J.L.A. Wood ◽  
J.W.A. Grant ◽  
M.H. Belanger
Keyword(s):  
Rainbow Trout ◽  
Population Density ◽  
Oncorhynchus Mykiss ◽  
Population Size ◽  
Local Population ◽  
Minimum Size ◽  
Territory Size ◽  
Stream Channels ◽  
Juvenile Rainbow Trout ◽  
Rainbow Trout Oncorhynchus Mykiss

We manipulated population density of juvenile rainbow trout ( Oncorhynchus mykiss ) across a range of realistic densities in artificial stream channels, while controlling food abundance in two different ways: in Experiment 1, the total amount of food was held constant over a threefold increase in density, whereas in Experiment 2, the per capita amount of food was held constant over an eightfold increase in density. We tested the contrasting predictions that territory size (i) is not affected by population density; (ii) decreases with population density as 1/n, where n = the local population size; or (iii) decreases with population density but towards an asymptotic minimum size. In Experiment 1, territory size decreased with increasing population density. With the broader range of densities used in Experiment 2, territory size initially decreased with density and then leveled off at a minimum territory radius of 20–30 cm. Our results suggest an asymptotic minimum size of about 0.2 m2 for a 5 cm rainbow trout, similar to what is observed for high-density conditions in the wild. This minimum territory size could potentially set an upper limit on local population density and help regulate the population size of stream salmonids.

scholarly journals Graded Incorporation of Defatted Yellow Mealworm (Tenebrio molitor) in Rainbow Trout (Oncorhynchus mykiss) Diet Improves Growth Performance and Nutrient Retention

Animals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 187 ◽  
Author(s):  
Paulo Rema ◽  
Subramanian Saravanan ◽  
Benjamin Armenjon ◽  
Constant Motte ◽  
Jorge Dias
Keyword(s):  
Body Composition ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Growth Performance ◽  
Tenebrio Molitor ◽  
Nutrient Digestibility ◽  
Protein Meal ◽  
Yellow Mealworm ◽  
Juvenile Rainbow Trout ◽  
Rainbow Trout Oncorhynchus Mykiss

Insects are emerging as a sustainable alternative to fishmeal and fish oil in aquafeeds. This study assessed the effect of graded incorporation levels of defatted yellow mealworm (Tenebrio molitor) protein meal on juvenile rainbow trout (Oncorhynchus mykiss) growth performance, body composition, and apparent nutrient digestibility. The trial comprised five dietary treatments: control diet with 25% fishmeal, and four experimental diets with yellow mealworm protein meal at 5%, 7.5%, 15%, or 25%, which corresponded to a fishmeal replacement of 20%, 30%, 60%, or 100%, respectively. After 90 days, the graded incorporation of insect protein meal led to a significant stepwise increase in final body weight, and a significant improvement of specific growth rate, feed conversion ratio, and protein efficiency ratio compared to the control treatment. Regardless of the incorporation level, the insect protein meal had no effects on fish whole-body composition and apparent digestibility coefficients of dry matter, protein, fat, phosphorus, and energy. Protein, phosphorus, and energy retention significantly increased in fish fed the diets with an insect protein meal. In conclusion, the yellow mealworm protein meal could effectively replace 100% of fishmeal in the diet of juvenile rainbow trout with positive effects on its overall zootechnical performance.

Changes in Habitat Use and Feeding Chronology of Juvenile Rainbow Trout (Oncorhynchus mykiss) in Fall and the Onset of Winter in Silver Creek, Idaho

1993 ◽  
Vol 50 (10) ◽  
pp. 2119-2128 ◽  
Author(s):  
Michael D. Riehle ◽  
J. S. Griffith
Keyword(s):  
Rainbow Trout ◽  
Habitat Use ◽  
Oncorhynchus Mykiss ◽  
Density Distribution ◽  
Stomach Contents ◽  
Early Morning ◽  
Invertebrate Drift ◽  
Juvenile Rainbow Trout ◽  
Rainbow Trout Oncorhynchus Mykiss

We assessed changes in density, distribution, and microhabitat of age-0 rainbow trout (Oncorhynchus mykiss) in Silver Creek, a partially spring-fed stream, by periodic snorkeling in August 1987 through January 1988. We examined trout stomach contents and invertebrate drift samples in diel collections in August, September, October, and January to test if the period of feeding shifted from daytime to nighttime, concurrent with a transition to day concealment. In late September, fish aggregated briefly during the day and then began to conceal themselves in macrophyte beds, undercut banks, and submerged sedges and grasses along streambanks as temperature dropped below 8 °C in early October. Fish emerged from concealment at night, and numbers of trout visible were greatest 30–60 min after sunset and about 30 min before sunrise. Periods of peak feeding changed from afternoon and evening in August and September, when fish were day active, to mainly at night in October after the initiation of day concealment. Trout did not feed upon abundant chironomids in the daytime drift in October. In January, fish fed at 1–4 °C on mayflies, and stomachs were fullest in the early morning. Observations suggest that Silver Creek trout experienced a metabolic deficit that began in September.

scholarly journals Integrated multi-biomarker responses of juvenile rainbow trout (Oncorhynchus mykiss) to an environmentally relevant pharmaceutical mixture

2021 ◽  
Vol 221 ◽  
pp. 112454
Author(s):  
Mahaut Beghin ◽  
Mélodie Schmitz ◽  
Stéphane Betoulle ◽  
Olivier Palluel ◽  
Sébastien Baekelandt ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Juvenile Rainbow Trout ◽  
Rainbow Trout Oncorhynchus Mykiss

scholarly journals Bioaccumulation of metals in juvenile rainbow trout (oncorhynchus mykiss) via dietary exposure to blue mussels

Chemosphere ◽  
2017 ◽  
Vol 188 ◽  
pp. 548-556 ◽  
Author(s):  
Gillian McEneff ◽  
Brian Quinn ◽  
Matthew Bennion ◽  
Sorcha Dolan ◽  
Kathleen O'Rourke ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Dietary Exposure ◽  
Blue Mussels ◽  
Juvenile Rainbow Trout ◽  
Rainbow Trout Oncorhynchus Mykiss

scholarly journals Long-term exposure to low 17α-ethinylestradiol (EE2) concentrations disrupts both the reproductive and the immune system of juvenile rainbow trout, Oncorhynchus mykiss

2020 ◽  
Vol 142 ◽  
pp. 105836
Author(s):  
Kristina Rehberger ◽  
Elena Wernicke von Siebenthal ◽  
Christyn Bailey ◽  
Patrick Bregy ◽  
Melanie Fasel ◽  
...  
Keyword(s):  
Immune System ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Juvenile Rainbow Trout ◽  
Rainbow Trout Oncorhynchus Mykiss
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