A dwindling population of Chinese white dolphins was at risk from howitzers in the Da-an River Estuary on Taiwan's west coast, a major habitat for the dolphins, the Taipei-based Wild at Heart Legal Defense Association said.

"The military is not showing any regard for the welfare of this critically endangered group of dolphins," said Christina Macfarquhar, a researcher at Wild at Heart.

Only about 100 of the animals, also known as "Eastern Taiwan Strait Humpback Dolphins," remain, Macfarquhar said.

Last year, the dolphins were listed as "critically endangered" by the International Union for Conservation of Nature, the world's largest conservation network.

The population is unique to Taiwan, with skin pigmentation and other attributes not generally found in other Chinese white dolphin populations in Asia, she said.

Threats to the animals include fishing nets, pollution and loss of habitat amid industrial development and poorly regulated fishing practices.

Since the IUCN placed the dolphin population on its "red list," the administration of President Ma Ying-jeou has done little to protect the animal, environmental groups in Taiwan say.

For Wild at Heart, the military's exercises underscored the administration's lack of concern.

Asked for comment, military media liaison officer Col. Ben Wang confirmed the exercises, saying shells had been fired into the water.

But he said he was unaware of concerns about the dolphins.

"Taiwan has Chinese white dolphins?" he asked, adding, "This isn't the first time we've conducted these exercises -- these are regular maneuvers."

Macfarquhar said the military had participated in Cabinet-level meetings on protecting the dolphins, "so they should be aware of this issue."

"The fact that they're firing shells right into the habitat shows how much attention they've paid to it," she added.