River of dolphin blood (Image: Brooke McDonald Sea Shepherd Conservation Society/AP)

Fishermen in Japan have adopted a new way of killing dolphins in drive hunts – but the method is no more humane than the previous techniques, say vets and dolphin behaviour experts.

Japanese dolphin culls received global attention in 2009, after the release of the Oscar-winning documentary The Cove. It showed in graphic detail how each year, hundreds of dolphins were herded into a cove near the fishing village of Taiji, and killed with knives and spears. In the film the cove waters turned crimson with blood.

In 2010, Toshihide Iwasaki of Far Seas Fisheries and Yoshifumi Kai of the Taiji Fisheries Cooperative reported on another supposedly more humane method to cull dolphins. This involves using a thin rod to impale dolphins behind their blowhole and sever the spinal cord.


They said tests had shown that the animals died faster and as a consequence the method was adopted officially. In the case of four striped dolphins (Stenella coeruleoalba), the shortest time to death was said to be 5 seconds, considerably less than the 300 seconds using conventional practices.

Covert footage

A new study refutes these claims. “Our analysis shows that this method does not fulfil the internationally recognised requirement for immediacy,” says Andrew Butterworth of the University of Bristol Veterinary School, UK. “It would not be tolerated or permitted in any regulated slaughterhouse process in the developed world.”

Butterworth and his colleagues assessed video footage of the Taiji cull, filmed covertly in 2011 for German conservation group AtlanticBlue. They say dolphins took longer to die than the Japanese team claim. One striped dolphin, say Butterworth and colleagues, was still moving 254 seconds after being impaled.

They add that the criteria used in the Japanese report to determine time of death – termination of breathing and movement – is flawed. Any animal that has just had its spinal cord severed is likely to stop moving, they say. And dolphins are known for their ability to hold their breath for extended periods of time.

In drive hunts the animals are tethered to boats by their tail flukes to herd them into the culling cove. “From a scientific, humane, and ethical perspective, [this] sharply contradicts animal welfare standards employed in most modern and technologically advanced societies,” says team member Diana Reiss of City University in New York.

“In the US and UK, regulations and guidelines governing the humane treatment and slaughter of animals prohibit the killing of an animal in the presence of other animals.”

‘Hypocrites’

A Taiji fisheries official told me in 2009 that such reactions were “hypocritical” and “racially motivated”, saying that spinal cord transection was also practised on chickens and other animals in the West. The new study argues that accuracy is a problem when severing the spinal cord in large animals like dolphins.

Ultimately, blood loss induces first paraplegia and later death, says the report. The process is prolonged by inserting a wooden peg into the wound, which Iwasaki and Kai said was done to prevent water contamination and to conserve the blood for commercial use.

Lori Marino of Emory University in Atlanta, Georgia says the decision to focus on the culling method is unfortunate as it implies there is a humane way to kill a dolphin.

Asked if there are other killing methods that would be considered more humane, Reiss said: “The killing of dolphins is indefensible given our scientific knowledge of dolphins, which has demonstrated their sophisticated cognitive abilities including self and social awareness.”

“We should ensure that dolphins receive the highest standards of treatment in any hunt, equal to that granted to domestic animals,” says Kris Simpson of International Dolphin Watch. “This is clearly not being achieved, nor, under conditions in the wild, is it ever likely to be. Our position is therefore unequivocal; the dolphins must not be hunted.”

Journal reference: Journal of Applied Animal Welfare Science, DOI: 10.1080/10888705.2013.768925