New Zealand Journal of Marine and Freshwater Research abstracts
Migratory behaviour of spawning rainbow trout (Oncorhynchus mykiss)
in the Tongariro River, New Zealand, after habitat alteration
Mark R. Venman
Michel Dedual
Department of Conservation
Private Bag
Turangi, New Zealand
email: mvenman@doc.govt.nz
Abstract The movements of 92 adult rainbow trout (Oncorhynchus
mykiss) from Lake Taupo into the Tongariro River, New Zealand, were monitored
using radio-telemetry every 3 days during the main spawning period between
May and November 2003. This study repeated one previously conducted in 1995.
Differences in spawning site preference and resting locations between 1995
and 2003 probably reflect differences in the nature of the river as a result
of major natural floods that occurred in 1998. Average migration times were
slower than in 1995 and the correlation between flow and mean daily movement
was less distinct owing to the dry and settled weather during July and August,
although fish did respond to freshets when they occurred. Peak movement occurred
between 1600 and 2000 h NZ Standard Time with no movement occurring between
midnight and 0400. Fish adjusted their movement in response to changing photoperiod.
Nineteen fish were observed above the mouths of natal tributary streams for
several weeks in the main river stem before entering these tributaries.
Keywords rainbow trout; spawning migration; Tongariro
River; radio-telemetry; fish movement; habitat alteration
M04140; Online publication date 17 June 2005 Received 4 October 2004;
accepted 4 March 2005
New Zealand Journal of Marine and Freshwater Research, 2005, Vol. 39:
951-961
0028-8330/05/3904-0951 © The Royal Society of New Zealand 2005
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