New Zealand Journal of Marine and Freshwater Research abstracts
Seasonal movements of short-beaked common dolphins
(Delphinus delphis) in the north-western Bay of Plenty,
New Zealand: influence of sea surface temperature and El Niño/La
Niña
DIRK R. NEUMANN
Centre for Tourism Research
Massey University
Private Bag 102 904
North Shore MSC, Auckland
New Zealand
email: D.R.Neumann@massey.ac.nz
Abstract Movement patterns of small cetaceans are influenced
by a great number of variables including prey availability, sea floor profile,
thermocline, oxygen minimum layer, and sea surface temperature (SST). Presented
here are data on short-beaked common dolphins (
Delphinus delphis L.) in
New Zealand, showing a seasonal offshore-shift in their distribution, which
appears to be correlated with SST.
D. delphis moved from a mean distance
of 9.2 km (SD = 4.42) from shore in spring and summer to a mean distance
of 20.2 km (SD = 3.86) from shore in autumn. During warmer La Niña
conditions their mean distance from shore was further reduced to only
6.2 km (SD = 2.56), and offshore movement was delayed by a month.
Worldwide,
D. delphis can be found throughout a wide range of sea
temperatures, and it is therefore unlikely that SST is the primary factor
influencing their distribution. It is hypothesised, that SST influences the
distribution of
D. delphis prey, which in turn affects their seasonal
movements.
Keywords common dolphins; Delphinus delphis; sea
surface temperature; distribution; El Niño; La Niña
M00070
Received 4 October 2000; accepted 13 November 2000
New Zealand Journal of Marine and Freshwater Research, 2001, Vol. 35:
371-374
0028-8330/01/3502-0371 $7.00 (c) The Royal Society of New Zealand
2001
PDF file of entire paper: medium quality (284K); (scanned from paper original: notes about this process)
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