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Management Implications of Ecological Segregation between Two Introduced Populations of Cutthroat Trout in a Small Colorado Lake
Author(s) -
Trojnar John R.,
Behnke Robert J.
Publication year - 1974
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(1974)103<423:mioesb>2.0.co;2
Subject(s) - trout , salvelinus , catostomus , oncorhynchus , biology , ecology , fishery , intraspecific competition , fishing , predation , competition (biology) , salmo , sucker , zoology , fish <actinopterygii>
Ecological differences reflected in food and habitat preference and angling vulnerability were investigated between two introduced sympatric populations of cutthroat trout, Salmo clarki. The Pikes Peak cutthroat fed to a large extent on Daphnia (68% by volume), whereas the Snake River cutthroat fed primarily on terrestrial insects (68% by volume). Other food habit differences were observed in the brook trout, Salvelinus fontinalis, and rainbow trout, Salmo gairdneri, populations. The Snake River cutthroat trout was more vulnerable to angling than the Pikes Peak cutthroat. This was due in part to the opportunistic and surface feeding behavior of the Snake River cutthroat and angling restrictions which resulted in most fishermen angling on or near the surface. The Pikes Peak cutthroat had a high mortality rate during August and September. This coincided with the period of greatest competition with the longnose sucker, Catostomus catostomus, for Daphnia. The results illustrate the practical application of intraspecific variability in fisheries management programs. The establishment of interacting populations of the same or different species can result in more efficient use of the food resources of a lake and greater fish production. It is urged that every effort be made to preserve the remaining genetic diversity in polytypic species such as S. clarki.