13 September 2007

Antarctic Seals on Sydney Beaches - “ The anatomy of a sea lion is not too dissimilar to the human anatomy”

Pack-ice animals in Sydney?
The arrival of seven 'debilitated' sub-Antarctic Leopard Seals on the coast of NSW is unprecedented. Two Leopard Seals, malnourished, injured and near death, were washed on to Sydney's beaches (Wattamolla, Clovelly Beach) recently. Scientists are 'baffled' about the “seven animals in the last two months” which are out of their habitat. Living on Antarctic ice shelves normally they are 'out of place'. ”If they get this far north, they are very sick.” said a NPWS wildlife management officer.
The Leopard Seal (Hydrurga leptonyx) inhabits Antarctic pack ice as most of the time as a top predator catching Penguins, Squid and Krill. Antarctic Krill makes up 45 % of its diet, for which the species has specially adapted teeth.

Inhospitable coasts – nowhere to rest
Seals in distress, being marine and terrestial are in need of rest. On a densely populated coast, 'real estate' for seals only remains in name as 'Seal Rocks'. Authorities implore the public to allow animals to rest ("hauling-out") on the foreshore and not allow their dogs to savage and harass them. A fur seal also had to be disentangled out of a shark net recently. 'Fishing gear and plastic litter' are the other human-made hindrances for these marine mammals.

Krill- the stuff that feeds most
Krill are the keystone species of the food web for many, such as Leopard Seals, whales, penguins, squid and fish. The bioluminescent Antarctic Krill grazes on drifting algae and small zooplakton. “ Most krill species display large daily vertical migrations, thus feeding predators near the surface at night and in deeper waters during the day.” Like a lawnmower, they also “scrape the green lawn of ice -algae from the underside of the pack ice.”

Human induced changes on the planet:
Human activities heating up the planet, deprive the inhabitants of these extreme cold regions, of their habitat. The melting ice and associated higher temperatures are a threat to the fauna.

Effects of a changed globe:
The 'Death March of the Penguins' in the Antarctic continues, numbers are dwindling. “As cracks, gaps and relocated chunks appear, it becomes harder and harder for penguins to forage under the ice for Krill or make their way quickly to the water.“ Landlocked animals cannot reproduce. Where penguins interface with human dwellers (Tasmanian coast) and their pets, the outcomes are predictable: “Dogs are capable of killing a penguin just by closing their jaws on the penguin's skull… A few years ago, 50 to 60 penguins were killed by dogs in one night."

At the Earth's northern region: the Arctic
Seals are running out of ice lairs for their pups, both polar bears and indigenous hunters will get to feel their absence as a direct effect of the warming.

With the disappearance of the sea ice, walruses are out of solid ground. ”Pinnipeds are carnivorous aquatic mammals that use flippers for movement on land and in the water. All pinnipeds must come ashore to breed, give birth and nurse their young. That platform has been shrinking.”

'Skinny' Grey Whales - warmer temperatures and vanishing sea ice are forcing them to find non-customary food sources.” But switching food could expose them to parasites that contribute to their emaciated condition

Bering Sea wildlife species are threatened by an array of complex problems, including commercial fishing, global climate change and pollution ”. 12 % of all vertebrates are at risk.

Homeless beings, out of food and rest get sick
Malnourished seals, whales and penguins, struggling to reproduce also have to live in water bodies saturated with pathogens and toxins. A weakened immune system is more susceptible to pathogens.

The case of toxic algae and bacteria pandemic killing seals
There has been “... a steady upswing in beach strandings and mass die-offs of whales, dolphins and other ocean mammals on U.S. Coasts...More than 14,000 seals, sea lions and dolphins have landed sick or dead along the California shoreline in the last decade. So have more than 650 gray whales along the West Coast. ” It was found that seals had ingested toxic algae bloom accumulated in anchovies and sardines. “ The surge in mortality has coincided with what Florida wildlife pathologist Greg Bossart calls a "pandemic" of algae and bacteria...” Fuelled by human waste and other nutrients of coastal areas the 'bad bugs' explode. “Toxic algae thrive on the same elements that turn lawns green and make crops grow — nitrogen, phosphorus and iron

One bug, Pseudo-nitzschia, covering '155 square miles of coastal waters produces' a potent neurotoxin. Anchovies and sardines eat the red tide organisms unharmed, but if they in turn get eaten by seals, they get the accumulated toxic dose. The domoic poisoning disorients the animals and they lose orientation. “Some swam hundreds of miles out to sea and were never seen again, bizarre behavior for creatures that spend their lives in coastal waters.” Usually, they are emaciated , disoriented, suffer seizures, and finally the hippocampus becomes severely atrophied. One is reminded, that “ The anatomy of a sea lion is not too dissimilar to the human anatomy.”

The displacement of the inhabitants of the Antarctic and Arctic might be a sign that the Earth is being turned into a hot and in-hospitable place for all, a primordial atmosphere.


On the Use of Water - Or the Creation of Dead Zones
Drinking Water & Healthy Water Bodies Pt II
Drinking water security, sewage and emerging bugs III

- Altered Oceans, Kenneth R. Weiss, Usha Lee McFarling and Rick Loomis (Toxic algae that poison the brain have caused stranding and mass die-offs of marine mammals — barometers of the sea's health.)
- Penny Chisholm,
Video: The Invisible Forest: Microbes in the Sea
- Earth Observatory, NASA

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