Summary
The diet of Salmo gairdneri and S. trutta in a Pyrenean stream was very similar, and was also similar to the percentage composition of the drift but not the benthos. There was a good correlation between diel changes in the amount of food (both numbers and biomass) in the stomachs and diel changes in the abundance of drifting invertebrates. The major feeding period was in the early hours of the night when the trout fed chiefly on benthic invertebrates in the drift. This was the only feeding period in experiments 1 and 2 (mean water temperatures 4.7 and 7.3° C) but in experiment 3 (10.8° C), there was a second feeding period in the day when terrestrial invertebrates and emerging aquatic insects formed a large proportion of the diet.
Neither species was consuming a greater amount of food than the other. The weight of food consumed/trout/day increased with water temperature, and was close to the daily food requirements for resting metabolism in experiment 1. for twice resting metabolism (active metabolism) in experiment 2, and for four times resting metabolism in experiment 3. Therefore the energy of the second meal in experiment 3 was available for growth.
The effect of temperature, on rates of gastric evacuation was the chief factor which determined the number of meals/day; the availability of food organisms in the drift determined the time of feeding; and the requirements for metabolism (affected by temperature and body weight) determined the amount of energy left for growth.
Similar content being viewed by others
References
Chaston, I.: Seasonal activity and feeding pattern of brown trout (Salmo trutta) in a Dartmoor stream in relation to availability of food. J. Fish. Res. Bd Can. 26, 2165–2171 (1969).
Décamps, H.: Ecologie des trichoptères de la vallée d'aure (hautes-pyrénées). Ann. Limnol. 3, 399–577 (1967).
Elliott, J. M.: Daily fluctuations of drift invertebrates in a Dartmoor stream. Nature (Lond.). 205, 1127–1129 (1965).
Elliott, J. M.:The food of trout (Salmo trutta) in a Dartmoor stream. J. appl. Ecol. 4, 59–71 (1967a).
Elliott, J. M.: Invertebrate drift in a Dartmoor stream. Arch. Hydrobiol. 63, 202–237 (1967b).
Elliott, J. M.: Diel changes in invertebrate drift and the food of trout Salmo trutta L. J. Fish Biol. 2, 161–165 (1970).
Elliott, J. M.: Rates of gastric evacuation in brown trout, Salmo trutta L. Freshwat. Biol. 2, 1–18 (1972).
Elliott, J. M., Corlett, J.: The ecology of Morecambe Bay IV. Invertebrate drift into and from the River Leven. J. appl. Ecol. 9, 195–205 (1972).
Jenkins, T. M.: Night feeding of brown and rainbow trout in an experimental stream channel. J. Fish. Res. Bd Can. 26, 3275–3278 (1969).
Jenkins, T. M., Feldmeth, C. R., Elliott, G. V.: Feeding of rainbow trout (Salmo gairdneri) in relation to abundance of drifting invertebrates in a mountain stream. J. Fish. Res. Bd Can. 27, 2356–2361 (1970).
Krogh, A.: Respiratory exchange of animals and man. London: Longmans, Green & Co. 1916.
Paloheimo, J. E., Dickie, L. M.: Food and growth of fishes. II. Effects of food and temperature on the relation between metabolism and body weight. J. Fish. Res. Bd Can. 23, 869–908 (1966).
Tanaka, H.: On the nocturnal feeding activity of rainbow trout (Salmo gairdnerii) in streams. Bull. Freshwat. Fish. Res. Lab. (Tokyo) 20, 73–82 (1970).
Tuša, I.: On the feeding biology of the brown trout (Salmo trutta m. fario L.) in the course of day and night. Zool. Listy 18, 275–284 (1969).
Winberg, G. G.: Rate of metabolism and food requirements of fish. Fish. Res. Bd Can. Transl. Ser. No 194 (1956).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Elliott, J.M. The food of brown and rainbow trout (Salmo trutta and S. gairdneri) in relation to the abundance of drifting invertebrates in a mountain stream. Oecologia 12, 329–347 (1973). https://doi.org/10.1007/BF00345047
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00345047