RT Journal Article
T1 Ontogenetic Shifts in Terrestrial Reliance of Stream-Dwelling Brown Trout
A1 Sánchez-Hernández, Javier
A1 Cobo, F.
K1 Allochthonous resources
K1 Feeding
K1 Inter-individual variation
K1 Ontogeny
K1 Prey accessibility
AB This study focuses on terrestrial reliance of brown trout (Salmo trutta) and compared it to the potential prey available (macrozoobenthos and drifting invertebrates) in three temperate rivers (Galicia, NW Spain), with special emphasis on variations in terrestrial energy intake through the ontogeny of brown trout. Additionally, we paid particular attention to individual variation of terrestrial resource use within and between age classes. Prey items were grouped in four categories: i) aquatic invertebrates; ii) imagoes of aquatic invertebrates; iii) terrestrial invertebrates; and iv) fish prey. Next, energy composition was measured according to dry weight-energy equations for each individual in line with above-mentioned prey categories. Our findings illustrate that terrestrial invertebrates appeared to be scarce in the environment, whereas aquatic food resources were rather abundant and accessible. The use of terrestrial invertebrates tended to increase with age, but with a high degree of inter-individual variation in resource use. In fact, the individual reliance of brown trout on terrestrial invertebrates may vary considerably (between 0% and 76.9%). Besides, the frequency of terrestrial foragers, i.e., individuals with terrestrial invertebrates in their stomachs, increased with age, except in one population which had the maximum value in the age-2 class. The acquisition of terrestrial invertebrates thus appears to be a process strongly dependent upon the actual food availability in the environment, but with a high degree of individual variance in resource use within the same age class. Finally, we discuss that terrestrial invertebrates may largely contribute to cover the energy intake of the species, highlighting the interface between terrestrial and aquatic ecosystems, and thereby the importance of riparian canopy cover as a key factor for food supply of stream-dwelling salmonids species
PB PAGEPress
YR 2016
FD 2016-07-01
LK http://hdl.handle.net/10347/16025
UL http://hdl.handle.net/10347/16025
LA eng
NO SÁNCHEZ-HERNÁNDEZ, JAVIER and COBO, FERNANDO, 2016, Ontogenetic shifts in terrestrial reliance of stream-dwelling brown trout. Journal of Limnology. 2016. Vol. 75, no. 2. DOI 10.4081/jlimnol.2016.1322. PAGEPress Publications
NO The authors would like to thank the staff of the Station of Hydrobiology of the USC ‘Encoro do Con’ for their participation in the field work. Wealso appreciate the constructive comments on the manuscript given by one anonymous referee. J. Sánchez-Hernández was supported by apostdoctoral grant from the Galician Plan for Research, Innovation, and Growth 2011-2015 (Plan I2C, Xunta de Galicia)
DS Minerva
RD 25 abr 2026