Wednesday, 13 February 2008

Australia tries to solve mystery of disappearing Minke whale numbers

Despite Japan's assurances that whale numbers are at sustainable levels, the case for its annual whale kill is not that simple. 
In 2000 the International Whaling Commission admitted that Minke whale numbers in the Southern Ocean had probably been overestimated.
Research has shown these whales are not experiencing a population boom as argued by Japan.
"A female sperm whale may produce one calf every five years, after reaching sexual maturity at nine years. Males reach breeding age in their late twenties. It is not known how many calves a female may bear before reaching menopause or the rate of natural sperm whale mortality. A young whale may suckle from her mother for up to 15 years.----
Scientists believe that it takes around 20 years on average for a female whale to replace itself with one mature female offspring. This does not account for the potential adverse impacts of new human-induced threats to whales such as bycatch, climate change, ozone depletion, marine pollution, ship strikes and underwater noise pollution."
After twenty years of international Minke whale surveys, Australia is now using aerial surveys.
"For the first time, Australian scientists will use aircraft to count minke whales in the pack ice around Antarctica.
Since 1978 the International Whaling Commission (IWC) has been counting whales in the Southern Ocean for management and conservation purposes. Each year ships, provided by Japan, cover about one-tenth of the Southern Ocean, with each survey in the unstrengthened vessels necessarily ending at the edge of the pack ice around Antarctica. Thus, every 10 years, a circumpolar snapshot of whale abundance is obtained.
Surveys over the past two decades, however, suggest there has been a significant decline in minke whale abundance, leading to disputes over whether the decline is genuine, or an artefact caused by the survey technique.
One theory is that changes in the ice edge boundary each year, and changes in the number of minke whales present in the pack ice beyond this boundary, could be responsible for the differences in estimates of the whales in open water. In other words, could there be more minke whales hiding under the hundreds of kilometres of pack ice (and open areas within the pack ice), where the ships can't search?"
Japan's whale meat market has been slashing prices since 2002 and still the general public has not taken to eating whale meat on a regular basis.

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