New Zealand Journal of Marine and Freshwater Research abstracts
Movements of the New Zealand school shark, Galeorhinus galeus, from tag
returns
ROSEMARY J. HURST1
NEIL W. BAGLEY1
GRAEME A. MCGREGOR2
MALCOLM P. FRANCIS1
1National Institute of Water & Atmospheric
Research Ltd
P. O. Box 14 901, Kilbirnie
Wellington, New Zealand
email: r.hurst@niwa.cri.nz
2Ministry of Fisheries
P. O. Box 3437
Auckland, New Zealand
Abstract During the period March 1985 to January 1997, 3950
school sharks,
Galeorhinus galeus (L),
were tagged,
mostly opportunistically during other research activities. Up to July 1997, 207
sharks had been recaptured. The best recovery rates were from sharks tagged
with internal (8.8%) and dart (6.5%) tags and first caught by line methods
(22%). The maximum distance travelled was 4940 km, the maximum time at
liberty was 3505 days (9.6 years), and greatest average speed was
22.8 km/day. Most sharks (76%) moved less than 500 km, but the larger
movements included 10% of sharks which had travelled over 1700 km to
southern Australia. The proportion of sharks recaptured in their home Quota
Management Areas (QMA) was 53% overall. However, the distance travelled
increased significantly with time at liberty. After 2 years at liberty, only
22% of sharks were recaptured within a release QMA and 23% were recaptured in
Australia. These findings suggest that future assessment of school shark
fisheries within New Zealand waters should consider the species as one stock
with a relatively high emigration rate to Australian waters.
Keywords school shark; Galeorhinus galeus;
tagging; movements; New Zealand; Australia
M98030
Received 16 June 1998; accepted 24 September 1998
PDF file of entire paper: medium quality (1956K); (scanned from paper original: notes about this process)
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