Evaluating techniques for sampling stream crayfish (Paranephrops planifrons)
作者:
CharlesF. Rabeni,
KevinJ. Collier,
StephanieM. Parkyn,
BrendanJ. Hicks,
期刊:
New Zealand Journal of Marine and Freshwater Research
(Taylor Available online 1997)
卷期:
Volume 31,
issue 5
页码: 693-700
ISSN:0028-8330
年代: 1997
DOI:10.1080/00288330.1997.9516799
出版商: Taylor & Francis Group
关键词: crayfish;population structure;depletion;mark‐recapture;electrofishing;New Zealand
数据来源: Taylor
摘要:
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.
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