New Zealand Journal of Marine and Freshwater Research abstracts
Mortality and tag loss in dart and loop-tagged captive snapper, Pagrus
auratus (Sparidae), with comparisons to relative recapture rates from a
field study
DAVID McGLENNON
South Australian Research and Development
Institute
Aquatic Sciences
P. O. Box 120
Henley Beach, SA 5022
Australia
DEBORAH PARTINGTON
South Australian Research and Development
Institute
Biostatistics Unit
Plant Research Centre
Waite Research Precinct
Urrbrae, SA 5064
Australia
Abstract Tag shedding rates of Hallprint dart and loop tags,
and tag-related mortality in the snapper
Pagrus auratus were
experimentally determined on fish held in captivity for periods up to 18
months. An artefact of the experimental process appeared to exacerbate dart tag
shedding in one treatment. However, for other treatments, the instantaneous
shedding rates for the first 7 months was 0.0006 day
-1. Shedding
rates were not linear for periods beyond 7 months and were described by a
logistic function. The instantaneous shedding rate for the loop tags was much
lower at 0.00016 day
-1. Overall mortality during the experiment was
only 1.9% and the causes of death could not be related to tagging. The relative
return rates of the two different tag-types from a field tagging programme were
compared after analysis of fish size, spatial, temporal, and tagger-type
distribution. In all direct comparisons within each stratum, loop tag return
rates were higher. It was concluded that the retention capabilities are better
for loop tags than for dart tags in
P. auratus.
Keywords Pagrus auratus; tag shedding; tagging
mortality; recapture rates
New Zealand Journal of Marine and Freshwater Research, 1997: Vol. 31:
39-49
0028-8330/97/3101-0039 $2.50/0 (c) The Royal Society of New Zealand
PDF file of entire paper: medium quality (847K); (scanned from paper original: notes about this process)
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