Periodic variability in cetacean strandings: links to large-scale climate events.
Cetacean strandings elicit much community and scientific interest, but few quantitative analyses have successfully identified environmental correlates to these phenomena. Data spanning 1920-2002, involving a total of 639 stranding events and 39 taxa groups from southeast Australia, were found to demonstrate a clear 11-13- year periodicity in the number of events through time. These data positively correlated with the regional persistence of both zonal (westerly) and meridional (southerly) winds, reflecting general long-term and large-scale shifts in sea-level pressure gradients. Periods of persistent zonal and meridional winds result in colder and presumably nutrient-rich waters being driven closer to southern Australia, resulting in increased biological activity in the water column during the spring months. These observations suggest that large-scale climatic events provide a powerful distal influence on the propensity for whales to strand in this region. These patterns provide a powerful quantitative framework for testing hypotheses regarding environmental links to strandings and provide managers with a potential predictive tool to prepare for years of peak stranding activity.
Evans
K
K
School of Zoology, Antarctic Wildlife Research Unit, University of Tasmania, Hobart, Tasmania, Australia. karen.evans@csiro.au
Thresher
R
R
Warneke
R M
RM
Bradshaw
C J A
CJ
Pook
M
M
Thiele
D
D
Hindell
M A
MA
D000818:Animals; D002591:Cetacea; D002980:Climate; D009791:Oceanography; D010507:Periodicity; D013648:Tasmania; D014739:Victoria; D014919:Wind