New Zealand Journal of Marine and Freshwater Research abstracts
Evaluating techniques for sampling stream crayfish
(Paranephrops planifrons)
CHARLES F. RABENI
Missouri Cooperative Fish and Wildlife
Research Unit
Biological Resources Division
U.S. Geological Survey
112 Stephens Hall, University of Missouri
Columbia, Missouri 65211, United States
KEVIN J. COLLIER
STEPHANIE M. PARKYN
National Institute of Water & Atmospheric
Research Ltd
P. O. Box 11 115
Hamilton, New Zealand
BRENDAN J. HICKS
Department of Biological Sciences
University of Waikato
Private Bag 3105
Hamilton, New Zealand
Abstract We evaluated several capture and analysis techniques
for estimating abundance and size structure of freshwater crayfish
(Paranephrops planifrons) (koura) from a forested North Island, New
Zealand stream to provide a methodological basis for future population studies.
Direct observation at night and collecting with baited traps were not
considered useful. A quadrat sampler was highly biased toward collecting small
individuals. Handnetting at night and estimating abundances using the depletion
method were not as efficient as handnetting on different dates and analysing by
a mark-recapture technique. Electrofishing was effective in collecting koura
from different habitats and resulted in the highest abundance estimates, and
mark-recapture estimates appeared to be more precise than depletion estimates,
especially if multiple recaptures were made. Handnetting captured more large
crayfish relative to electrofishing or the quadrat sampler.
Keywords crayfish; population structure; depletion;
mark-recapture; electrofishing; New Zealand
New Zealand Journal of Marine and Freshwater Research, 1997, Vol. 31:
693-700
0028-8330/97/3105-0693 $7.00/0 (c) The Royal Society of New Zealand
1997
PDF file of entire paper: medium quality (647K); (scanned from paper original: notes about this process)
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