Moments before it happened, Ken Isaacs, a crew member on a whale-watching vessel, realized the tourists on his boat were about to witness something terrible.

While touring open water around the small Caribbean island of St. Vincent, the crew spotted a pod of four orcas, also known as killer whales, breach the water's surface. As the tourists delighted at seeing orcas in the wild, Isaacs frantically shouted at three fisherman who were approaching in a small craft. Isaacs took note of the modified harpoon gun mounted to their deck.

Ignoring Isaacs's pleas, the fishermen closed in on the pod. The group of 40 tourists heard what sounded like an explosion.

Right before their eyes, one of the orcas in the pod had been speared with a harpoon. A second soon met the same fate.

Isaac's account, as told to Caribbean 360, said the tour group returned to shore shaken, with many of the guests crying. Fantasea Tours, which operated the whale-watching outing, has reportedly suspended its tours.

Now, local paper the Antigua Observer is reporting a renewed push to outlaw the killing of orcas in the waters controlled by the island. In an interview with local news, St. Vincent Prime Minister Ralph Gonsalves towed the line when advocating for a total ban on orca fishing, which is a means of subsistence of some on the island.

"What he did, I want to emphasise this, what he did was plain wrong. Not just because it happened in front of tourists, but (because) he must not kill the orcas," Gonsalves said.

He emphasized that the fishermen were "very hard working" but later added that "their greed [got] the better of them."

Spurred by the incident, Gonsavles is now saying he will put forth legislation in St. Vincent that prevents killing of orcas, similar to the island's local protections for sea turtles.

The incident has also sparked debate about whaling in the region.

The island, which is located in the southern Caribbean just north of Venezuela, has a complex history with whaling. Officially called St. Vincent and the Grenadines, it is a voluntary member nation of the International Whaling Commission.

Under stipulations set forth by the international agency, whaling is allowed when done by "indigenous people to satisfy subsistence needs," according to the organization's website. The nation is allowed to kill four great whales every year, and it has reportedly slaughtered six since 2015.

The IWC doesn not, however, regulate hunting small cetaceans such as orcas, meaning there is no international limit on their killing in St. Vincent.

Sue Fisher, a consultant with the Whale and Dolphin Conservation Society, says that the legal allowances for whaling in general in St. Vincent are an outlier, since most other countries allowed to kill whales are near the Arctic. She considers the whaling practice an oversight by the IWC, saying the island was initially a base for commercial whaling practices conducted by companies in the U.S.

"Yankee whaling was a commercial operation," says Fisher. "The understanding by the commissioners [of the IWC] was that whaling would provide nutritional subsistence."

Whale hunting by the Bequia (pronounced beck-way) people in St. Vincent is a tradition that dates back roughly 140 years. The practice was reportedly brought to the island's locals by Scottish immigrant William Wallace after he established a whaling company and passed knowledge to the country's citizens.

After commercial whaling companies left the island, the practice was maintained by a small few. For some, such as Fisher, this prompts debate about whether whaling should truly be considered a cultural practice.

Advocates for a total ban on whaling also argue that emerging technology no longer means that whales are the only form of subsistence for indigenous people.

Some of the island's former whale hunters have turned to whale watching as an alternative method of profiting from orcas and whales.

In order to continue legal great whaling practices, St. Vincent would need to present the IWC with a statement of need when their whaling license expires in 2018. Fisher theorizes that the island will not do so as they benefit more from tourism than they do whaling.

In a 2014 interview with the Miami Herald, former fisher Gaston Bess recalled being moved to give up the practice after observing killer whales off the coast of the Dominican Republic, saying, “even though I had been around them, struck them and watched them die, now I was watching them ballet, caressing their young.”

While the incident was a shock for tourists at sea, St. Vincent hunts a comparatively low amount of whales annually. A report by the Congressional Research Service found that of the countries for which the IWC allows a hunting exemption, St. Vincent hunted great whales in the single digits, while 51, 128, and 203 were killed in the U.S., Russia, and Greenland respectively in 2012.

These numbers do not encompass the number of orcas killed.

By far the largest number of great whales killed annually occurs in Norway, which hunts in direct objection to the IWC, and Japan, which claims its whaling is conducted for scientific research.