Dolphin hunts in the Solomon Islands, a cultural tradition, may threaten the survival of this species, according to new research. It also is casting a spotlight on the increasing vulnerability of small cetaceans around the world.

While whale hunts - particularly those that occur in Japan - gain more attention, this new study shows that "drive-hunting" dolphins should also be a major concern. These friendly marine animals are valued for their teeth, of all things, which are used to make jewelry.

In fact, from 1976 to 2013, more than 15,000 dolphins were killed by villagers in Fanalei alone, where a single dolphin tooth can fetch the equivalent of 70 cents ($0.70 USD) - an increase in value of five times just in the last decade.

"In the Solomon Islands, the hunting is as much about culture as economic value," study co-author Scott Baker, associate director of the Marine Mammal Institute at Oregon State University, said in a news release. "In other parts of the world, however, the targeting of dolphins and other small cetaceans appears to be increasing as coastal fishing stocks decline.

"The hunting of large whales is managed by the International Whaling Commission," he added. "But there is no international or inter-governmental organization to set quotas or provide management advice for hunting small cetaceans. Unregulated and often undocumented exploitation pose a real threat to the survival of local populations in some regions of the world."

But controlling the number of dolphins killed in the Solomon Islands may prove to be difficult. That's because the drive-hunting of dolphins has a long history in the Solomon Islands, particularly at the island of Malaita, according to researchers.

Remarkably, in 2010, the most active village, Fanalei, suspended hunting - in exchange for financial compensation from an international non-governmental organization. However, the villagers quickly resumed hunting in 2013.

"After the agreement broke down in 2013, a local newspaper reported that villagers had killed hundreds of dolphins in just a few months," noted Marc Oremus, a biologist with the South Pacific Whale Research Consortium and lead author on the study. "So we went to take a look."

Oremus and his colleagues visited Fanalei in March 2013 to document the impact on the local dolphin population, and examine detailed records of the kills. During the first three months of that year, villagers killed more than 1,500 spotted dolphins, 159 spinner dolphins, and 15 bottlenose dolphins - one of the largest documented hunts of dolphins in the world. (Scroll to read on...)

It even rivals the more-industrialized hunting of dolphins in Japan, Baker said - such as those that occur in Taiji's Hatajiri Bay, commonly known as "the cove," where dolphins are commonly corralled in large groups.

"It is also troubling that teeth are increasing in cash value, apparently creating a commercial incentive for hunting dolphins," the researcher added.

In drive-hunting, the hunters operate in close coordination from 20 to 30 traditional canoes. When dolphins are found, the hunters used rounded stones to create a clapping sound underwater. The hunters maneuver the canoes into a U-shape around the dolphins, using sound as an acoustic barrier to drive them toward shore where they are killed.

"The main objective of the hunt is to obtain dolphin teeth that are used in wedding ceremonies," Oremus said. "The teeth and meat are also sold for cash."

What's more is that the Solomon Island hunters understand the risk of exploiting the population, though they continue their drive-hunts.

"The government of the Solomon Islands has contributed substantially to research in recent years, but is not well-equipped to undertake the scale of research needed to estimate abundance and trends of the local dolphin population," Oremus said. "This problem exists in many island nations with large 'Exclusive Economic Zones.'"

Hopefully this and other research will be able to shed more light on how drive-hunting dolphins impacts these animals, as well as other small cetaceans, and will allow policymakers to come up with a sensible solution.

For more great nature science stories and general news, please visit our sister site, Headlines and Global News (HNGN).