New Zealand Journal of Marine and Freshwater Research abstracts
Relative effects of in-stream habitat and land use on fish distribution and
abundance in tributaries of the Grey River, New Zealand
IAN G. JOWETT
JODY RICHARDSON
National Institute of Water & Atmospheric
Research Ltd
P. O. Box 11-115
Hamilton, New Zealand
R. M. McDOWALL
National Institute of Water & Atmospheric
Research Ltd
P. O. Box 8602
Christchurch, New Zealand
Abstract The distribution and abundance of fish was
investigated over 2 years at 78 sites in Redjacks Creek and adjacent
tributaries draining native, exotic, and mixed forest catchments within the
Grey River system, South Island, New Zealand. The abundance of diadromous fish
decreased with altitude and distance from the sea, whereas the abundance of
non-diadromous fish species, especially dwarf galaxias (Galaxias
divergens), increased with altitude and distance from the sea. Species
abundance varied with average stream depth and velocity, generally in
accordance with micro-habitat preferences. The relative influences of diadromy,
land use, and physical habitat on fish distribution and abundance were
difficult to separate. Differences in fish abundance in the three land-use
categories were often attributable to differences in physical habitat.
Nevertheless, there were indications that land use and its effect on the stream
environment was influencing the distribution of some fish species. Ammocoetes
(Geotria australis) were least abundant in native forest catchments,
whereas dwarf galaxias and bluegilled bullies (Gobiomorphus hubbsi) were
abundant in those catchments. Banded kokopu (Galaxias fasciatus) were
associated with in-stream cover and only found in the smallest streams sampled.
The abundance of torrentfish (Cheimarrichthys fosteri) and bluegilled
bullies declined over the study period, and three fish species were found in
catchments adjacent to Redjacks Creek, but not in Redjacks Creek or its
tributaries. Suspended sediment produced by mining and logging activities may
have caused low fish diversity and changes in fish abundance in Redjacks
Creek.
Keywords land use; physical habitat; diadromy; fish
abundance; fish distribution
New Zealand Journal of Marine and Freshwater Research, 1996: Vol 30:
463-475
0028-8330/96/3004-0463 $2.50/0 (c) The Royal Society of New Zealand
1996
PDF file of entire paper: medium quality (1073K); (scanned from paper original: notes about this process)
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