New Zealand Journal of Marine and Freshwater Research abstracts
Links between climate variation and the year class strength of New Zealand
hoki (Macruronus novaezelandiae) Hector
MARY E. LIVINGSTON
National Institute of Water & Atmospheric
Research Ltd
P. O. Box 14 901, Kilbirnie
Wellington, New Zealand
email: m.livingston@niwa.cri.nz
Abstract Hoki (
Macruronus novaezelandiae) Hector year
class strength (YCS) varies substantially from year to year. In this study,
potential links between hoki YCS estimates for western and eastern stocks, and
time series of the Southern Oscillation Index (SOI), satellite sea surface
temperatures (SST), synoptic weather patterns, depth of the mixed layer
(western stock only), and wind speeds are explored. The results indicate that
favourable recruitment in the western stock is correlated with a negative SOI
and associated conditions such as lower SSTs, early onset of deep water mixing
and synoptic weather patterns that result in a higher incidence of south-west
(SW) flow. Favourable recruitment in the eastern stock appears to be correlated
with periods of westerly flow, particularly from the SW, but also the
north-west (NW). Regression studies showed that when inter-correlation was
minimised, 95% of the variation in YCS of the western stock was explained by
four variables--SOI in autumn, the onset of winter mixing, SST in spring, and
NW spring weather patterns. In the eastern stock, 88% of the variation in YCS
was explained by SW and NW winter weather patterns and the average speed of SW
winds in winter through Cook Strait. Although the underlying mechanisms are not
proven, the climate variables which appear to be linked to favourable
recruitment for both western and eastern stocks, also favour upwelling and the
physical transportation of larval hoki from the spawning grounds into their
respective inshore nursery areas.
Keywords hoki; recruitment; climate
M99026
Received 7 May 1999; accepted 27 August 1999
PDF file of entire paper: medium quality (1074K); (scanned from paper original: notes about this process)
This year's abstracts |
Journal home page |
All abstracts |
Publishing home page
