New Zealand Journal of Marine and Freshwater Research abstracts
Comparative dietary analysis of a recently described fish species complex
(Galaxiidae) in a New Zealand river
RICHARD M. ALLIBONE*
COLIN R. TOWNSEND
Department of Zoology
University of Otago
P. O. Box 56
Dunedin, New Zealand
*Present address: National Institute of Water & Atmospheric Research Ltd,
P. O. Box 11 115, Hamilton, New Zealand. email: r.allibone@niwa.cri.nz
Abstract The diets of several populations of four recently
described species of galaxiid with allopatric distributions were examined in
the Taieri River, New Zealand. Comparisons of available prey items and prey
consumed were carried out to examine whether the distributions of the galaxiid
species might be influenced by food availability and preferences. Seventy-three
prey categories were identified. The availability of four of these
(Deleatidium, Oligochaeta, Elmidae larvae and adults) differed among the
streams occupied by different galaxiid species. Three differences in the
frequency of prey consumption (Deleatidium, Oxyethira, and
Elmidae larvae) were detected. Despite differences in diet it was concluded
that all four fish species were generalist predators of invertebrates with
similar diets that were influenced mainly by prey availability. Furthermore
prey availability was not considered responsible for the allopatric
distribution of the four species, rather, spawning habitat availability,
physical nature of the streams, and prior geological history of the Taieri
catchment are considered the controlling influences on galaxiid distribution.
Keywords Galaxias; diet; prey availability;
distribution
M97024
Received 27 June 1997; accepted 4 May 1998
PDF file of entire paper: medium quality (798K); (scanned from paper original: notes about this process)
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