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https://theconversation.com/falls-in-whale-sightings-rare-seabirds-appearing-is-something-unusual-happening-in-the-southern-ocean-287961>
"In late June, whale watchers in southwest Western Australia sounded the alarm.
They had seen far fewer humpback whales at a time when they normally migrate up
from the Southern Ocean to calve and feed. Numbers were 60% below normal.
A week later, birdwatchers spotted a “once in a lifetime event” as large
numbers of rarely seen albatrosses and petrels appeared off Australia’s east
coast, thousands of kilometres from their usual foraging grounds deep in the
Southern Ocean. Many birds were in poor condition.
The sightings came just weeks after a dying migratory seabird was confirmed as
Australia’s first case of highly pathogenic H5N1 bird flu.
These sightings raise troubling questions. Seabirds and marine mammals such as
whales use ocean currents and weather to travel long distances to feeding and
breeding grounds. If these species are changing their behaviour, it could be a
sign of altered conditions in the Southern Ocean.
We know the world’s oceans are running very hot. Marine heatwaves can affect
any part of the ocean – even frigid Antarctic regions. If species are used to
water temperatures around 2–6°C, a sudden boost of a couple of degrees can
upend ecosystems. If the heatwave lingers, the cumulative effect can be much
bigger.
We don’t yet know for sure, as monitoring in the Southern Ocean is limited. But
we know marine heatwaves can alter currents, weather conditions and prey
availability."
Cheers,
*** Xanni ***
--
mailto:xanni@xanadu.net Andrew Pam
http://xanadu.com.au/ Chief Scientist, Xanadu
https://glasswings.com.au/ Partner, Glass Wings
https://sericyb.com.au/ Manager, Serious Cybernetics
