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https://theconversation.com/southern-right-whales-are-having-fewer-calves-what-this-says-about-ocean-health-266375>
"Most people are lucky to simply get a glimpse of some fragment of a whale. A
subtle puff of mist over the horizon, the curve of a dark smooth back sliding
beneath the surface, or for the fortunate, the flash of a tail or the explosive
splash of 40 tons of flesh pounding the surface of the water when they breach.
The immense satisfaction experienced during these brief appearances is a
testimony to the whales’ elusiveness, and the immense difficulty of studying
them.
For scientists, the challenge is even greater: whales spend most of their lives
far offshore, hidden beneath the waves, or even well within the ice pack in
some of the most remote and inhospitable oceans on Earth.
This difficulty has driven researchers to creative extremes – like using
crossbows to gather skin samples, flying helicopters to count them, and
sticking cameras with suction cups on their backs. I faced the challenge myself
during my doctoral research at the University of Pretoria, which set out to
unravel how southern right whales are responding to the combined pressures of
climate change and shifting ocean ecosystems.
Southern rights are the species that draws thousands of visitors to Hermanus, a
town on South Africa’s southern Cape coast, each spring when they reach peak
numbers at their calving grounds. They generally start arriving here in June
after feeding for a couple of years in the Antarctic, and generally all leave
by November back into the Southern Ocean.
Southern right whales are one of the three species of right whales worldwide.
All belong to the baleen whale group – the filter-feeding giants that include
the blue, humpback and fin whales. Reaching up to 17 metres in length, they are
among the larger whale species. The southern right is the only right whale
found in the southern hemisphere, with populations off South America, South
Africa, Australia and New Zealand.
My research shows that the South African population of southern right whales is
being squeezed by climate change in the Southern Ocean. Their reproductive
slowdown is a clear biological signal of environmental disruption: fewer calves
in Hermanus most likely means there is less food under the ice thousands of
kilometres away.
This has two important implications. First, it highlights the vulnerability of
whale populations. These animals face an uncertain future in a warming ocean.
Second, it demonstrates the remarkable role whales can play as sentinels. By
monitoring their health and behaviour, we gain insight into vast, remote
ecosystems that are otherwise costly and difficult to study."
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
