New Zealand Journal of Zoology abstracts
Fine-scale genetic structuring in endemic galaxiid fish populations of the
Taieri River
T. M. KING*
G. P. WALLIS
Department of Zoology and Centre for Gene Research
University of Otago
P. O. Box 56
Dunedin, New Zealand
*Present address: Ecology Section, Massey University, Private Bag 11-222,
Palmerston North, New Zealand.
Abstract Many of New Zealand's
Galaxias species have
declined in abundance this century. Some stream-resident species are now
restricted to sections of tributaries above waterfalls >3 m in height
that act as barriers to the predatory brown trout (
Salmo trutta). It has
been suggested that these spatially isolated populations are also genetically
isolated and as a result experience restricted gene flow. We used isozyme
electrophoresis to test this hypothesis. Comparisons were made between and
within tributaries at sites separated by waterfalls. Results from six
polymorphic loci showed evidence of genetic heterogeneity among populations of
G. anomalus and
G. depressiceps from tributaries of the Taieri
River system, South Island, New Zealand. In one instance, heterogeneity was
found within a single tributary. This demonstrates that gene flow among
populations is restricted and that waterfalls are likely to be a significant
influence in controlling galaxiid population structure.
Keywords Galaxias anomalus; G. depressiceps;
brown trout; isozyme electrophoresis; gene flow; population structure
Received 28 June 1996; accepted 6 October 1997
PDF file of entire paper: medium quality (457K); (scanned from paper original: notes about this process)
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