MANILA - Environmental group Save Philippine Seas on Wednesday launched an online petition urging American children's television network Nickelodeon and local officials to junk plans for the construction of an underwater theme park in Coron, Palawan.

Save Philippine Seas executive director Anna Oposa said 400-hectare undersea project would destroy the area's world-famous marine ecosystem.

"Contrary to the press statement that the underwater theme park would 'advocate ocean protection,' it will accomplish the exact opposite. By building artificial structures, you will undeniably damage and disrupt Palawan's marine ecosystems -- our Last Frontier," Oposa said in a statement.

"For a channel that targets children, Nickelodeon is setting a terrible example to the younger generation by taking away their right to enjoy our natural resources. We don't need an underwater theme park -- our underwater life is fascinating, entertaining, and educational on its own."

She urged Nickelodean to invest instead in marine protected areas, sustainable livelihoods for local communities, and environmental education programs.

SPS's petition against the theme park has garnered 50,000 online signatures in its first three hours.

Nickelodean, the firm behind SpongeBob SquarePants and Dora the Explorer announced Monday that the park in Palawan would showcase the area's marine life that would give fans a chance to "interact with the brand and the iconic characters they love."

Palawan was chosen for the development because it "is known to have some of the most beautiful beaches in the world today," Ron Johnson, an executive vice president with Viacom International Media Networks, which owns Nickelodeon, said in a statement emailed to AFP on Tuesday.

Viacom said the resort would open in 2020 and feature restaurants and lounges six meters below sea level.

Viacom's Philippine partner, Coral World Park, insisted the resort would not hurt the environment.

"We are taking very, very careful measures to ensure that the biodiversity is kept intact," Coral World Park chairman Paul Monozca said.

The Palawan Council for Sustainable Development, a government body, said the project had yet to be approved.

Conservation groups call Palawan "the last frontier" because of its pristine coastlines and forests, which are among the oldest and most diverse in Southeast Asia.

Palawan is home to two UNESCO World Heritage-listed sites, a subterranean river and the Tubbataha coral reefs.

-- With Agence France-Presse