It is believed to be a beaked whale, which are rarely seen because they spend long periods underwater.
Melting sea ice from climate change has opened up the region for giant whales to undertake "feeding frenzies".
The humpback whale later successfully freed itself after the tide rose in Queensland, Australia.
Experts say the whales were away from their natural habitat.
Scientists are also tracking the movements of porpoises and whales in the 10-day survey.
It follows several social media posts in recent days reporting sightings in the sea.
Six beluga whales have arrived in Illinois and Texas after being moved from a Canadian marine park that could no longer care for them.
The juvenile North Atlantic right whale was caught in 1907 and has been in storage for six years.
The deceased Sowerby's beaked whale is "a rare sight on the Thames Estuary".
