The DNA profiling and capture-recapture analysis allowed the researchers to estimate how long an individual whale was available for sale in the markets ?a process they compare to the decay of radio-isotopes. Fewer meat products from an individual whale remain on the market with each succeeding week, and their estimate of six weeks for the "half-life" of an individual whale gives future researchers a good idea of how frequently they will need to survey markets.
Whale meat is rarely frozen in Korea. It is usually par-boiled immediately after purchase by wholesalers or retailers and then sold over the next few weeks in thick slices of skin, blubber and meat ?usually without refrigeration.
Using their "capture-recapture" model, which is based on statistical probability, the researchers estimate that the true number of minke whales that likely passed through Korean markets from 1999 to 2003 was probably 827 individuals, or nearly twice the number in official reports.
"If the mortality is really twice as great as the number reported to the government and to the International Whaling Commission, it has major implications for the survival of the species," Baker said. "Researchers who have done sighting surveys of minke whales report difficulty in even locating the whales, and it has been hard to reconcile the small numbers sighted at sea with the numbers reported via bycatch.
"This means that there is no accepted estimate of the total abundance of this population," Baker added, "but it seems likely that it is small and declining because of the unregulated exploitation."
The study focused on minke whales in the Sea of Japan known as "J stock.
Source:Oregon State University