BATHURST, N.B. -- Animal rescuers hope to capture and relocate an endangered beluga whale that has been making its home in a northern New Brunswick river for several weeks.

Tonya Wimmer of the Marine Animal Response Society said they hope to relocate the juvenile whale from the Nepisiguit River to the St. Lawrence Estuary near Cacouna, Que., but it's a major effort to gather all the resources and develop a plan to keep the whale safe.

"It will hopefully be some point this week," Wimmer said Tuesday. "We would like to help the animal out of the river as soon as possible. They can be in fresh water but they're not designed to be there permanently."

Wimmer said the area near Cacouna is where other beluga whales usually spend their summer months.

She said it's unknown why this whale went off on its own and decided to stay in the fresh water river.

"Many times it is because they are following fish that happen to be running. We have had some cases where it's an animal that has just gotten confused and gets lost basically," she said.

Wimmer said the whale -- about two metres long -- appears healthy for now, but shows no indication it plans to leave the river on its own.

She said capturing, moving and releasing the whale will be risky, but officials have determined it is the best option.

"It was a natural case for us to say we needed some sort of intervention to either herd the animal out of the river or try to capture it and take it out of the river," Wimmer said.

The whale will be equipped with a tracking device so scientists can observe where it goes.

Fisheries and Oceans, and the Group for Research and Education on Marine Mammals are also major players in the relocation effort.

The population of the St. Lawrence belugas has been declining since the early 2000s and it's believed there are fewer than 900 of them still in existence.

They were placed on the endangered species list last fall.

-- By Kevin Bissett in Fredericton.