The population of Antarctic minke whales has not increased even though larger whales they competed with for food were whittled down by hunting, according to a recent study by U.S. researchers, countering arguments Japan cites as a reason for conducting lethal research.
The Fisheries Agency and researchers have hypothesized that Antarctic minke whales may have increased as a result of lesser competition for the krill they feed on.
But researchers at Oregon State University and Stanford University calculated that the population size in the early 20th century was roughly 670,000, a figure similar to or slightly larger than current estimates from surveys of sightings.
They analyzed genetic diversity of minke whales by purchasing 52 meat samples in Japanese markets to project the population number, according to the study published in the journal Molecular Ecology, posted online in December.
Scott Baker, a researcher at Oregon State University who conducted the analysis, said the latest results indicated the hypothesis by some scientists that the population has increased by three-fold to eight-fold over the last century is wrong.
The Fisheries Agency has said in promoting the lethal research that there are calls for “thinning” Antarctic minke whales because that species could be hindering the recovery of the blue whale population.
Sea Shepherd clash
The antiwhaling group Sea Shepherd Conservation Society obstructed the activities of a Japanese whaling ship Monday in the Antarctic Ocean by pointing laser lights and discharging water at it, the Fisheries Agency said.
No one was injured during the protest over the research whaling, according to the agency.
At around 7 a.m. Japan time, the Nisshin Maru, the mother ship of the whaling convoy, was sandwiched by two Sea Shepherd boats and subjected to laser lights and water spray, according to the agency.
The Nisshin Maru issued warnings through loud speakers, it said.
The incident followed a collision between a whaling ship and a Sea Shepherd vessel Saturday.
Australia and New Zealand have called for restraint from both sides, with the antiwhaling activists deploying laser devices and stink bombs, and the Japanese fleet operating military-style acoustic weapons.