A possible false negative: Lack of evidence for trout predation on a remnant population of the endangered Macquarie perch, Macquaria australasica, in Cotter Reservoir, Australia

To investigate possible predation on a remnant population of the endangered Macquaria australasica in Cotter Reservoir, ACT, Australia, stomach content analysis was conducted on 63 rainbow trout Oncorhynchus mykiss and 24 brown trout Salmo trutta. Both predators were found to be piscivorous, with th...

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Bibliographic Details
Published in:New Zealand journal of marine and freshwater research 2007-06, Vol.41 (2), p.231-237
Main Authors: Ebner, Brendan, Broadhurst, Ben, Lintermans, Mark, Jekabsons, Mark
Format: Article
Language:English
Subjects:
Carassius auratus
Freshwater
introduced species
Macquaria australasica
Oncorhynchus mykiss
Percichthyidae
piscivory
Salmo trutta
Salmonidae
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Summary:To investigate possible predation on a remnant population of the endangered Macquaria australasica in Cotter Reservoir, ACT, Australia, stomach content analysis was conducted on 63 rainbow trout Oncorhynchus mykiss and 24 brown trout Salmo trutta. Both predators were found to be piscivorous, with the frequency of piscivory generally increasing with body size. Goldfish Carassius auratus were the only fish species identified in stomach contents. That gape-limitan on prevented trout from feeding on juvenile M. australasica was eliminated as a possibility based on: (1) the body depth of prey and the mouth-size of predators; and (2) evidence that another species of similar dimensions was ingested by trout. Whether or not trout predation on M. australasica is an important process in Cotter Reservoir remains to be clarified. Juvenile M. austalasica do not reside in the parts of the reservoir from which most trout were actually sampled in the current study. Therefore, it is proposed that the lack of evidence for predation on M. australasica is potentially a false-negative result.
ISSN:0028-8330
1175-8805
DOI:10.1080/00288330709509911