Amid increased attention and protests to annual dolphin hunts in Japan, local fisherman adopted a purportedly more humane way of killing dolphins, but new research shows that the method is still not up to international animal rights standards, according to a report by New Scientist.

The 2009 documentary "The Cove" brought international recognition to the practices of fishermen in Taiji, Japan for their use of knives and spears to kill hundreds of dolphins systemically driven into a cove off coast of Wakayama prefecture in western Japan. The film depicted cove's blue water turning to a bloody shade of crimson as the dolphins were killed.

In an apparent response in international and domestic criticism, the local fishermen's unions started using a thin rod to impale the dolphins behind their blowholes, which reportedly severs the spinal cord; a wooden wedge is placed in the would to prevent polluting ocean with blood. The fishermen reported the shortest death time to be five seconds, much less than the 300 seconds it would take for a dolphin to die using traditional methods.

But a new study from the University of Bristol Veterinary School in the U.K. refutes the fishermen's claims that the new method is more humane, saying it is exceedingly difficult to accurately sever a large mammal's spinal cord and that plugging up the would only prolongs death. They also note that the fishermen's method for determining death -- lack of movement and breathing -- is flawed because any creature with a servered spinal cord would stop moving and dolphins are able to hold their breath for long periods of time.

"Our analysis shows that this method does not fulfill the internationally recognized requirement for immediacy," said the veterinary school's Andrew Butterworth, according to New Scientst. "It would not be tolerated or permitted in any regulated slaughterhouse process in the developed world."

No hard data was available for researchers to analyze, so they turned to covertly taped video footage of the culling. The full text of the study is available here.

The researchers concluded there is "no logical reason to accept a killing method that is clearly not carried out in accordance with fundamental and globally adopted principles on the commercial utilization, care, and treatment of animals."

While the Japanese government sets yearly quotas that allow more than 2,000 dolphins and small whales to be killed in drive hunts, Ric O'Barry, Director of Dolphin Project, reports this year's dolphin hunting season, which ended last month, took slightly less than 900 dolphin's lives in Japan.

"Our contacts in Taiji told us that a release of pilot whales early in the season was due to the freezers in the slaughterhouse being full, which again suggests that the meat is not selling like it has in the past. The Taiji dolphin hunters have a quota of 2,089 this year - yet they again only killed about half of that amount."

However, in 2010 the mayor of Taiji told the Associated Press that the pracice of hunting dolphins is unlikely to change.

"We will pass down the history of our ancestors to the next generation, preserve it. We have a strong sense of pride about this," Mayor Kazutaka Sangen told the AP in an interview. "So we are not going to change our plans for the town based on the criticism of foreigners."