A dead humpback whale washed up in shallow water off a BC Ferries terminal in Tsawwassen, sparking questions about how the massive marine mammal perished.

The juvenile humpback whale was found near the Tsawwassen Causeway Friday morning, prompting a response from the Department of Fisheries and Oceans' Marine Mammal Response Team.

A Coast Guard hovercraft towed the whale to a base on Sea Island, where the whale was expected to undergo a necropsy to determine its cause of death.

"It's really important to figure out what's happened to this animal, why it's died, and make sure that if there is an anthropogenic or human cause, what that is," said DFO officer Paul Cottrell.

BC Ferries tweeted that its service was running as usual after the discovery of the whale carcass.

"We are saddened to hear about the whale that washed up near our terminal at Tsawwassen this morning," BC Ferries said in a tweet. "We'd like to let our customers know that traffic is flowing normally at this time."

The discovery made it a busy few days for DFO after a killer whale calf was found dead on Nootka Island Wednesday.

A necropsy is also underway on that whale to determine whether it belonged to the population of endangered southern resident killer whales that frequent the waters off B.C.'s coast.

Members of the local Tsawwassen First Nation say they'll be following the necropsy of the humpback to see if it died of natural causes, or something else.

"Very concerning," said Andrea Jacobs. "Of course we're hoping it was natural causes but definitely be following to see what actually happened."

One sparse in B.C. waters, experts have seen a humpback comeback in recent years.

While their resurgence is seen as a triumph, it opens the ocean giants to new risk factors.

"They are vulnerable to being struck by boats and ships," said marine biologist Anna Hall. "We don't really know why they are more vulnerable than some other species, other than they do tend to spend some time near the surface."

Cottrell said the DFO expected to know more about the whale's death by Saturday.

"It may be obvious, it may not be obvious," he said. "Often we can't find a cause of death."