Brook trout invasion into bull trout streams is variable, and likely influenced by a suite of
biotic and abiotic factors. Field observations revealed that brook trout dominated the fish
community over bull trout in warmer sites that had undercut banks; in contrast, bull trout
dominated in colder sites that had a high amount of large substrate cover, and where
alternate non-native species were present. Laboratory studies of competition between the
two species revealed that bull trout use a scramble foraging tactic, whereas brook trout
use a territorial tactic. Bull trout outcompeted brook trout when fish density was low and
habitat complexity was high, as this scenario reduced the effectiveness of the aggressive
territorial foraging strategy of brook trout. Bull trout from a migratory population
competed more successfully against brook trout and had higher rates of oxygen
consumption than those from a resident population. This combined field-lab study points
to some of the abiotic and biotic factors that affect competition between the two species,
and may influence the outcome of brook trout invasion into bull trout streams. / xiv, 184 leaves : ill. ; 29 cm
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:ALU.w.uleth.ca/dspace#10133/3377 |
| Date | January 2012 |
| Creators | Warnock, Will G |
| Contributors | Rasmussen, Joe |
| Publisher | Lethbridge, Alta. : University of Lethbridge, Dept. of Biological Sciences, c2012, Arts and Science |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | en_CA |
| Detected Language | English |
| Type | Thesis |
| Relation | Thesis (University of Lethbridge. Faculty of Arts and Science) |
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